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nliberto@powder
11-25-2009, 02:27 PM
Powder Coating Consulants (PCC) is an internationally recognized technical services company specializing in Powder Coating. We will provide free help to any member of SCCoA, as I am a member myself. Go to our website for more information www.powdercc.com.

Nick

nliberto@powder
03-17-2010, 06:20 PM
I thought I would "bump" my own thread to see if anyone needs powder coating advice.:D

Our firm charges $125 per hour for our expert help, and I am offering it for free to any SCCoA member. My Accountant and Wife frown :mad: when I give away free advice, but what the heck.:eek:

Ask away and play stump the Consultant! PM me or send an email directly to nliberto@powdercc.com. Our website is www.powdercc.com. You can even call on our toll free hotline (800) 97 POWDE(R). Operators (me that is) are standing by!:rolleyes:

qc89SC
03-17-2010, 10:34 PM
whats would be a starter set to make our own powder coating at home on small parts like spindle??? and where to buy equipment?

BLOWN38
03-17-2010, 11:36 PM
I would like to know the secret on how to keep eastwoods reflective chrome looking like chrome during the clearcoat stage?

I apply the chrome and bake it at 375 for 20 mins and it looks great. Then I apply the super gloss clear and set oven for 375 to bake the part and it turns alittle grey. First pic is before clear 2nd is after clear.

nliberto@powder
03-18-2010, 09:25 AM
Ok since we have two questions about the Eastwood powder coating system, I will combine them in one answer.

The first question is about "starter sets for powder coating"...The only company that I am aware of that makes complete kits for hobbyist (homeowner) powder coating is Eastwood. I had a hand in helping them select the ovens for their program and a few other technical issues over the years. They started out buying a "powder coating gun" from a China supplier that is pretty low-tech, but gets the job done. Sears and Summitt both have homeowner guns as well, but no ovens, etc. This gun uses a TV "fly-back" transformer to charge the powder during application, a far cry from industrial grade equipment. But it does not have the $4k price tag as the industrial equipment either. Once they had a gun, they needed all the other stuff to execute the powder process. They came up with a line of cleaning chemcials, cure ovens, booths, etc. to support the hobbyist and haven't looked back. Their real money maker is the powder they sell. Average powder coatings cost between $2.50 to $5.00 per pound (except the real sexy stuff) but come in one pound to 300 pound containers (automotive and appliance manufacturers buy their powder in 1500 pound totes!). Since the average homeowner does not need that much powder, Eastwood buys regular powder in 50 pound quantities and re-packages it into small containers. The price ends up at around $50.00 per pound. Nice business model!

To perform powder coating safely you need a spray gun, powder spray booth (designed for powder), cleaning method, and cure oven. The most expensive piece is the cure oven. You need the gun to charge and atomize the powder to get it to coat and stick to the part before placing it into the oven. You need the spray booth to contain the overspray and collect it for disposal (industrial users often re-use the overspray). Without a booth, you could have an explosion.:eek: You need a cleaning system to clean the parts before your apply the powder, because any paint job is only as good as the surface you apply it to.:rolleyes: You need the cure oven to heat the part above 250 degrees F to melt and cure the powder. Do not use your wife's cooking oven, as the next meal may not taste like you expect!:D Check the Eastwood website for current prices of these equipment components.

As for the question about clear coating over the silver (chrome) powder...Silver (chrome look-a-like) powders look great but have insufficient mechanical properties. They will scratch and mar easily. This is why they reccomend applying the clear over the top of the chrome powder. The clear can get cloudy, as seen in your picture, due to several issues. First, the quality of the clear powder may not be that great.:( Second, the thickness of the clear can affect the clarity of the coating (too much clear will get cloudy).:( Third, the clear can cloud up if it is under or over cured (under baked or over baked).:( Fourth the clear can cloud up if the oven does not have sufficient exhaust (oven contaminants).:(

Clears and chromes are "high risk" powder coatings, as they are very finicky to apply and still look good. Start out by buying a good clear powder. Apply it at less than 3 mils (0.003 inches) thick. Check cure by dipping a q-tip in MEK and rubbing it on the surface. The clear coating should not become sticky or tacky after 25 double rubs (one double rub is one single back & forth motion). If it does get soft, it is under cured. Finially increase your oven exhaust, if you have one, to improve the quality of the cured clear coating.

Sorry for the lengthy reply. It is just the Engineer in me comming out!:D

XxSlowpokexX
03-18-2010, 11:36 AM
Makes sence. Clears are always an issue but i can def see that happening when doing it over a chrome looking surface.

BLOWN38
03-18-2010, 07:11 PM
Makes sense. On the exhaust and the thickness of the coat. I'm just using a kitchen oven (not the one we cook food in) I guess doesn't have much exhaust. A fan does kick on on it sometimes. Maybe I should figure a manual override for the fan?

I have thought that its been the thickness of the clear, but when I've tried to change it some spots have come out dry and rough. I did an intake manifold and a part of it came out good where the clear didn't cloud and have tried to replicate it without success yet. I'll keep pluggin away at it.

Thanks for the reply. The worst part of powder coating is prepping the parts.:mad:

I am using the craftsman electric gun. It works well for me and what I use it for. I am getting better.

Here's a water outlet that came out great. This was before the clear.

Oh yeah, and whats gonna blow up if you don't have a booth?

Regul8r
03-18-2010, 11:10 PM
My question is on stock 90 wheels.

Looking to do them like the Annie cars but change the black to White AND make the center caps MATCH! Make the outer ring polished looking like the Annie's have.

How do I do that?
Can you do it? How much?

nliberto@powder
03-22-2010, 06:13 PM
Sorry folks, but since the weather got so nice in the Northeast the last couple of days I was out in the garage working on my 89 SC and did not check the posts for this thread lately. I check my emails frequently, but did not see anything from the SCCoA forum letting me know there were a few more posts!:eek:

Following are the next group of answers to the recently posted questions:

"I'm just using a kitchen oven (not the one we cook food in) I guess doesn't have much exhaust. A fan does kick on on it sometimes. Maybe I should figure a manual override for the fan?"

A kitchen oven does not have much exhaust at all, as it is designed to keep heat in and smoke out of your kitchen!;) Paint curing ovens on the otherhand have a heat source (gas burner or electric element), a circulation fan (convection heat type oven), and an exhaust fan. The heat source provides the heat energy, the circulation fan delivers the heat energy to the part, and the exhaust fan removes the by-product of combustion (natural gas only) and the by-products of powder cure. Having an oven with an inadequate heat source, no circulation fan, and inadequate exhaust will combine to cause numerous problems.

I recently answered a similar question for my Powder Coating magazine column last week:

Question: " i have been trying to powder coat a set of 350 chevy heads and when i shoot the heads with wet black powder and then cook them the powder is not flowing out it comes out as if it was never cooked. how can i get the parts to flow out. is it that the heads are soaking up the powder. please help me with this. i am baking at 500 degrees thank you for your help chris"

Answer: "Chris:

The 350 C.I.D. Chevy motor is very reliable. I had one in several vehicles over the year. However, I prefer the horsepower or the higher revving 327 C.I.D.

The description of the problem you are having tell me that you are not heating the cylinder heads to a point where the powder coating even melts, yet alone cures. If the powder on the part looks the same when you take it from the oven as when you put it in the oven (still a powder and not a coating), then it is time to evaluate what you are using to heat your part.

This problem has to do with the weight (mass) of the cylinder heads and the energy capacity of your heat source. I have lifted my share of Chevy heads over the years and from my recollection they weigh about 100 pounds. Considering that the cylinder head is made from steel and has a specific heat of 0.125 BTU per pound it will take 4,375 BTUs to head one cylinder head to 350 degrees F (the average cure temperature for powder coating). If you put this cylinder head into an oven whose heat source has an energy capacity of 1,000 BTUs per hour, it will take 4.375 hours to get the cylinder head up to temperature and an additional 25 minutes to fully cure the powder coating. That is almost five hours of “baking time”! However, if you use an oven with a heat source that has an energy capacity of 10,000 BTUs per hour it will take less than an hour. This relationship between the energy capacity of heat sources and cure time can easily be related to horsepower and speed; “The more you have the faster you will go!”.

I frequently tell my clients that the size of their oven burners determines how fast their products will achieve the desired powder cure temperature. I often tell them that you can cure a 10,000 pound part using a cigarette lighter, it will just take a couple of hundred years. The same goes for you. If you are trying to cure your cylinder heads in a toaster oven, then I hope you are very patient, as it will take quite a while to melt, flow, and cure the powder. Remember the old racer’s adage: “Go big or go home”. Of course, they were talking about engines (horsepower), but you get the point." :D

nliberto@powder
03-22-2010, 06:58 PM
Makes sense.
Oh yeah, and whats gonna blow up if you don't have a booth?:eek:

Powder coatings are "organic" in nature and, as susch, will combust if mixed with the right amount of air. The same thing applies to any organic dust, such as baking flour, sugar, etc. I am sure you have heard of tragic cases where a sugar mill or flour mill had an explosion.:eek::eek::eek: Well powder coating materials are just as dangerous! Believe me, as I have investgated numerous powder coating lines that had fires and explosions, some of which had fatalities!:(

The risk with powder coating is dramitically lower than using solvent type liquid paints (i.e. laquers, etc.). However, that does not mean that they are not dangerous in their own right.

Powder coatings will not combust (burn) in the container as there is too much powder (fuel) and not enough air.:cool: Same goes for the opposite condition, where a small amount of powder is mixed with a lot of air, the powder will not combust either.:) The problem occurs when powder coatings are atomized with just the right amount of air. This "just-right" mixture is between the "lower explosion limit" (LEL) and the "maximum explosion limit" (MEL) and is often the exact mixture of powder and air at the gun applicator tip. If a source of ignition is present with this "perfect mixture" the powder cloud will ignite!:eek: The result is a fireball that releases a tremendous amount of energy. If this energy is expended in a small area (what is called containment) the result is an explosion.

It is just like your SC engine works: gasoline is mixed with air and ignited in a contained area (the combustion chamber) and the resultant explosion sends the piston in the opposite direction. Ignite the same gasoline/air mixture in an open cup, and a fireball will happen, but no explosion since there is insufficient containment .:cool:

Most explosions happen when powder coating ungrounded (or improperly grounded) parts. The part will absorb some of the electrostatic energy used to charge the powder (so that it sticks to the part before curing). If the part is improperly grounded (more than one megohm = one million ohms resistance), the part will eventually become saturated with electrostatic energy and discharge to the closest ground (typically the gun tip). This results in an arc (ignition source) much like when you discharge static electricity in the wintertime after shuffleing your feet on a carpet and touch the light switch. The ignition source and the powder/air cloud cause a fireball at the end of the gun, the person spraying the powder usually screams and drops the gun, and the fire goes out harmlessly as the gun trigger is released stopping the power/air from fueling the fire. This event usually requires a change of clothes for the powder sprayer, at least their pants anyways!!!:D

However, if the person has been spraying a lot of powder in an enclosed garage, without ventilation, and there is a large cloud of power, then the next sound they hear is St. Peter asking them what they did back on earth to get into Heaven! The large powder cloud provides a significant energy source or fuel and air and the garage provides the containment...a very bad combination. The energy released from such an explosion is awesome. I have seen 40 feet of cinderblock wall moved 20 feet in a powder explosion!:eek::eek::eek:

Now that I scared the Sh-t out of you, it is time to bring you back to reality.:rolleyes: Powder coating is the safest method of painting, except for using laytex paint and a brush. Follow these important rules for safe powder coating:

1. Spray powder coatings in a powder coating booth that is designed with proper airflow. This ensures that there is not enough powder and too much air to have a combustion fireball (except right at the gun tip).

2. Always coat parts that are properly grounded. Use a ground wire attached to an electrical ground or cold water pipe at one end and attached to the part at the other end.

3. Eliminate all sources of ignition during spray operations. No smoking, no welding, no grinding, etc.

4. Cover all electrical devices within five feet of the spray area with air tight bags. Actually code requirements call for "dust tight explosion proof" electrical devices in this area, but they are very expensive.

5. Always wear a dust mask and safety glasses to protect your health when powder coating.

nliberto@powder
03-22-2010, 07:12 PM
My question is on stock 90 wheels.

Looking to do them like the Annie cars but change the black to White AND make the center caps MATCH! Make the outer ring polished looking like the Annie's have.

How do I do that?
Can you do it? How much?

Who is Annie???:confused:

Doing multiple colors (or no color) on the same part with powder coating can be very tricky. Each color has to applied separately and the other areas masked. The part needs to be partially cured between coats. This means that the masking materials must survive the cure oven (around 350 to 400 degrees F). There are numerous masking devices (tapes, plugs, etc) that can do this, but they are expensive and not available at Home Depot or the autopart store.

The easiest way to do what you want is to coat the wheel and caps separately using the colors you want. Cure both parts (cap and wheel). Remove the powder on the outer ring using a mild abrasive and polish it to a bright finish.

I have no idea what this would cost, but it sounds expensive!;)

Regul8r
03-22-2010, 07:14 PM
Nick,
any guidance on doing the Stock 90 rims up in white like the Black ones on a 35th?

Can you powder coat the center caps as well?

Would the rims need to be sand blasted to clear off the factory coatings?

BLOWN38
03-22-2010, 10:34 PM
Nick,
any guidance on doing the Stock 90 rims up in white like the Black ones on a 35th?

Can you powder coat the center caps as well?

Would the rims need to be sand blasted to clear off the factory coatings?

If the center caps are the aluminum ones you can powder them. The earlier wheels have metal centers, right?

Yeah you will want to strip the wheels to bare metal.

nliberto@powder
03-23-2010, 10:23 AM
If the center caps are the aluminum ones you can powder them. The earlier wheels have metal centers, right?

Yeah you will want to strip the wheels to bare metal.

Here are my recommendations for having your Aluminum wheels powder coated:

1. Remove the existing coating by either chemical stripping or media blasting. Do not use thermal stripping methods (burn-off oven) as the 1000+ degree heat will anneal (soften) the aluminum. NEVER USE THERMAL STRIPPING METHODS ON MAGNESIUM WHEELS, AS A FIRE WILL OCCUR THAT THE FIRE DEPARTMENT WILL HAVE GREAT DIFFICULTY EXTINGUISHING (AS WATER APPLIED TO BURNING MAGNESIUM WILL EXPLODE)!:eek: Acceptable blast media is Aluminum Oxide, CO2, or Plastic. Do not use steel based media, as it will start corrosion sites under the coating (galvanic reaction with the aluminum). Sand as a blast media has all but been outlawed (silicosis health problems).

2. Ask your powder coater if they can apply a chromate conversion coating to the aluminum wheels before powder coating. Sometimes reffered to as Alodine, this conversion coating will increase the service life of the coating by a factor of 5, or more.

3. Select either a TGIC polyester or Acrylic powder for your color, as these are the formulations that the original manufacturer used and are best suited for this application.

4. Consider using a clear coating over the color, for a better "depth of finish" and better wear life.

5. Instruct your powder coater to cure the coatings on the wheels at a temperature below 325 degrees F. This will ensure that you do not anneal the temper (hardness) of the aluminum. They will have to cure the wheels longer at this lower temperature, but it is the safe way to go!

This recipe will provide wheels that look great, will last a long time, and will not change the metalurgical charateristics of the wheel. :D

nliberto@powder
03-26-2010, 01:20 PM
Just a friendly Bump.

BLOWN38
03-26-2010, 01:51 PM
Is there a ratio for how much longer to cure when you cure at a lower temp? And whats the lowest cure temp?

When you are doing the multiple coats. What lenght of time should you partial cure? Like say you want to put a translucent color over a bright base like chrome? And then maybe clear the whole thing?

nliberto@powder
03-26-2010, 03:09 PM
Is there a ratio for how much longer to cure when you cure at a lower temp? And whats the lowest cure temp?

When you are doing the multiple coats. What lenght of time should you partial cure? Like say you want to put a translucent color over a bright base like chrome? And then maybe clear the whole thing?

Every powder coating is formulated to a time temperature curve. This curve shows the higher the cure temperatures the lower the cure times. However, each powder formula is unique in its curve. But rest assured that there are some basics that apply to all powder cure temperature/time relationships.:)

1. All temperatures quoted here and in any powder coating literature are "metal temperature" not oven temperature. That means that the temperature of the metal must be at the described tempearture, regardless of the oven setpoint.

2. Oven Dwell Time = Powder Cure Time + Part Bring-up Time. Therefore, the time you must cure a part in your oven is equal to the time it takes to heat your part to the desired temperature plus the cure time provided by the powder formulator.

3. All powder coatings must be heated to a 250 degree F metal temperature to begin melting on the part. But that does not mean that you can cure most powders at this temperature.

4. Some "low-cure" powder formulations can be cured at 250 degrees F metal termperture. However, the coating must be rated as "low temperature cure".

5. All powder cure curves have the same relationship: higher cure temperatures = shorter cure times and conversely lower cure temperatures = longer cure times.

6. Always follow the guidlines of the powder formulator for proper cure temperatures and cure times. Typical cure times are as follows: 400 degrees F metal tempearture for 10 minutes; 375 degrees F metal temperature for 15 minutes; 350 degrees F metal tempearture for 20 minutes; 325 degrees F metal temperature for 25 minutes; 300 degrees F for 30 minutes; 250 degrees F for 60 minutes.

7. Powder coatings typically have 100% overbake resistance built into the formula (except for clears, tinted clears, some metalics which have 50% overbake resistance, or less). This means that you can keep your part at the desired metal temperature for twice as long as the specified powder cure time without any detriment. This does not mean twice the oven dwell time!!!:eek: Therefore, if your powder has a cure time of 20 minutes at 350 degrees F and it takes 20 minutes for your part to reach 350 degrees F, you can leave your part in the oven for 40 minutes (minimum) and 60 minutes (maximum).:cool:

Now you know the whole story about cure!:D

nliberto@powder
03-29-2010, 06:12 PM
By the way, did you know you can cure some powder coatings in 30 seconds. It just requires the part to be at 600 degrees F metal temperature. :cool:

Normally, this is accomplished using high intensity infrared light to heat the surface of the part to 600 degrees F very quickly. This is how powder coatings are cured on a coil coating line at speeds up to 150 feet per minute. Of course, liquid coil coating lines run much faster, up to 300 feet per minute.:eek:

nliberto@powder
04-17-2010, 12:08 PM
Just a friendly Bump, for those who have yet to play "stump the consultant"!

XxSlowpokexX
04-17-2010, 01:42 PM
ok..Powdercoating magnesium :O)

nliberto@powder
04-18-2010, 02:33 PM
ok..Powdercoating magnesium :O)

Ok, smart a##. here goes::p

One needs to be carful when powder coating either tempered aluminum or magnesium, as both these substrates can be affected by the heat used to cure the powder coating. We don't have to worry about the magnesium catching fire, as the cure tempertures used for organic powder coatings are much lower than this ignition point. However, you can forget about removing powder coating from magnesium using thermal stripping methods (burn-off ovens), as this will catch the metal on fire!:eek:

So the trick becomes how do you cure powder coating on temperature sensistive metal substrates. As a definition, these metals are tempered (heat treated) alluminum and magnesium only, as heat treated steels have much higher tempering temperatures (above 1000 degrees F). Well, the answer is to use the lowest cure temperture provided by the powder formulator (supplier). As I stated in earlier answers in the thread, all powder coatings have a cure curve that shows time/temperature relationships that will cure the coating. This general cure principle shows that this curve starts at the lowest temperture for the longest time and goes to the highest temperature for the shortest time. Therfore to protect the heat temper on your alimunum and magnesium parts, you should choose a cure temperture no higher than 300 degrees. You will find that the cure time might be 30 minutes, or more, at this temperture, but it is better than annealing your aluminum or magnesium metal part.:rolleyes:

Oh yeah, don't foget to add the time it takes to bring your metal up to this temperature to determine your total oven cycle time!;)

I bet you thought you had me stumped with this question, didn't you?:D

XxSlowpokexX
04-18-2010, 04:46 PM
NAHHHHHHHHHHHHH haha Going to Carlisle? I dont see you preregistered!!!!

Actually I think a huge problem for us automotive guys is that powdercoat places generally just throw our parts in with thier other commercial stuff. Very litle care is taken in special prep or temperatures. I was thinking about getting a home setup together and experiementing. I get allot fo stuff done so the investment would be minimal for what I geeneral spend having someoen else do it!

nliberto@powder
04-20-2010, 05:47 PM
NAHHHHHHHHHHHHH haha Going to Carlisle? I dont see you preregistered!!!!

Actually I think a huge problem for us automotive guys is that powdercoat places generally just throw our parts in with thier other commercial stuff. Very litle care is taken in special prep or temperatures. I was thinking about getting a home setup together and experiementing. I get allot fo stuff done so the investment would be minimal for what I geeneral spend having someoen else do it!

Still on the fence aboutCarlisle, as I may have a business travel conflict.

Finding the right shop to perform small batch powder coating takes some effort. These businesses, called job shops, cater to a variety of customers. Some shops only do large coating jobs for business (industrial customers) while others specialize in small automotive work. Occasionally some shops do both kinds of work, although on different types of equipment.

The larger shops look at small automotive (or small motorcycle for that matter) powder coating projects as a nusiance, as it interupts their larger projects. These types of job shops should be avoided, as they may not provide the type of service you want.

Fins a smaller shop that caters to small automotive and motorcycle work. They charge a lot more for each job, but they perform small projects with an eye towards high quality, as most are car guys too.:D

For future reference, go to www.powdercoating.org (the Powder Coating Institute) www.pcoating.com (Powder Coating Magazine), and www.pfonline.com (Products Finishing Magazine) as they all have a list of "job shops" or "custom coaters" by geographical area. Some of these sites even describe the type of work they do or the size parts they can handle. Stay away from the high production shops and you will get good service.:)

nliberto@powder
04-29-2010, 04:41 PM
It was time to bump this back to the top again.

nliberto@powder
06-09-2010, 04:56 PM
It has been a while since the last question, so I thought I would give this thread a Bump!:)

XxSlowpokexX
06-09-2010, 05:57 PM
ok...So serious question. WHat is the most durable type of powdercoating for engine componants.

nliberto@powder
06-10-2010, 04:27 PM
ok...So serious question. WHat is the most durable type of powdercoating for engine componants.

Generally the following guidelines apply to powder coating properties:

Epoxy is very durable, oil and chemical resistent, but has no UV (sunlight) resistance. It will chalk readily in sunlight and look like bad aluminum siding in about 3 to 4 weeks. This low-cost material is often used on underhood and undercarriage parts where sunlight is not a problem.:)

Polyesters (TGIC or urethanes) have good durability (but not as good as epoxy), do not have great oil & chemical resistance, but have great UV resistance. This medium cost material is used on exterior trim parts and wheels.:)

Epoxy/polyester hybrids have some properties of both materials. They are not as durable as pure epoxy and not as UV resistent as polyester (just slightly better than epoxy). They are cheaper than polyester, but slightly more expensive than epoxy. The UV resistance is not sufficient to be used anywhere but on some hidden interior trim and underhood/undercarriage parts.:)

Acrylics are very hard (scratch resistent) and have superior UV resistance. These powders are often used in OEM wheel coatings. However, because they are catastrophically incompatable with polyester powders, no small shops spray them. :eek:

Choosing a powder by formula type may not be easy for the hobbyist due to availability from Eastwood and others. However, most job shops buy their powders directly from the formulator and can purchase whatever you want.:cool:

Now you can choose a powder for your application based upon your requirements and pocketbook.:p

XxSlowpokexX
06-10-2010, 05:15 PM
catastrophically incompatable

The greatest quote ever!

nliberto@powder
06-10-2010, 06:08 PM
The greatest quote ever!

Well I always had a way with words!:D

nliberto@powder
07-13-2010, 05:55 PM
I thought that I would bump this thread back to the top, just to let you all know that I am still here. Free advice for Powder Coating! At least until I go on vacation in August!:D

BLOWN38
07-13-2010, 09:40 PM
Have you ever tried to coat the plastic 4.6 2v valve covers? Can it be done with low heat? Or does it need the liquid coating?

nliberto@powder
07-14-2010, 01:56 PM
Have you ever tried to coat the plastic 4.6 2v valve covers? Can it be done with low heat? Or does it need the liquid coating?

There are low-temperature cure powder coatings on the market. However, even these require heating the part to at least 250 degrees F to melt the powder and form the coating, then the coating can be cured using UV or low temperature heat (> or = 250 F) depending upon powder formulation. Remember, unless you melt the powder you will never have a coating just powder particles, ergo "powder coating".:rolleyes:

Most plastics have a hard time handling the 250 degree F powder coating melt temperature. I am not sure what the 4.6 2V valve covers are made from, but I would guess that they could not handle the powder coating melt temperature.

The powder formulators (coating manufacturers) have not spent very much R&D developing coatings for plastics, as the main features of powder coatings (i.e. toughness, corrosion protection, etc.) do not apply to plastics since they inherently have these features without coating.:cool:

Considering that most people want to coat their plastic part to change or improve the color, the best bet is a good, durable, and flexible liquid paint. Visit an auto body supply house for their recommendations on which paint to buy. Scuff the plastic with a Scotchbrite pad and use a good prep solvent to clean the part before painting, taking care to fill any voids or surface imperfections. Using standard auto body preparation and painting techniques will be your best bet.:D

nliberto@powder
10-19-2010, 05:47 PM
Just a friendly bump, as it has been some time since anyone asked a Powder Coating question. I am starting to get bored. ;)

So...anyone want to play "stump the consultant"? :p

XxSlowpokexX
10-19-2010, 06:18 PM
Ok..So those clear with a tint powders. Can they be applied directly over a polished surface? Not really a stump question but I always figured there withd be durability issues without a rough surface to apply teh powder to.

nliberto@powder
10-20-2010, 11:57 AM
Ok..So those clear with a tint powders. Can they be applied directly over a polished surface? Not really a stump question but I always figured there withd be durability issues without a rough surface to apply teh powder to.

The trick with using tinted clears is to have the surface prepared to ensure that the final product provides the look you want. By definition "clears", tinted or otherwise, will show what is underneath them. Most people prefer to have the metal surface polished to a mirror to have a tinted mirror finish as the final result after coating. :cool:

Now just because you polish a surface does not mean tha you cannot obtain good coating adhesion. Although tinted clear parts are typically used in appearance locations on a vehicle and are not used in high abuse functional areas that require extremely great adhesion, you still need sufficient adhesion to ensure you are not recoating the part every year. To ensure good adhesion of any coating you must clean the part very well. Polished parts often have reminants of the polishing compound (rouge, polish, wax, and the like) that must be completely removed before coating. Be preapared to use a good cleaner and plenty of elbow grease to get the part completely clean. If the part is properly cleaned, you should not have a problem with adhesion.

Now let's discuss a part you want to have tinted clear that is used in a high-abuse area on your car (i.e. engine or chassis hardware). For this appiclation I would recommend that you clean the part, blast the surface for a good anchor pattern and then powder coat the part with a high gloss smooth silver (like a mirror chrome look-a-like coating). Now you can apply a tinted clear over this coating, have a great looking part that is very durable, and still look smooth and have a mirror finish. ;)

Thanks for the "softball" question. :p

nliberto@powder
04-30-2011, 11:24 AM
It has been some time since I bumped my own thread.:o

So here goes...time to play "stump the consultant!" :D

Ask you free question & get your answer...Answers are guaranteed to be of equal value!!!:p

XxSlowpokexX
05-01-2011, 11:59 AM
Hmmmm Best powder type for wheel applications. Not a stump question. Just seems allot of coaters I run into dont seem to understand the different types so much

BLOWN38
05-01-2011, 01:28 PM
Hmmmm Best powder type for wheel applications. Not a stump question. Just seems allot of coaters I run into dont seem to understand the different types so much

Good one. Cause the stuff mine where done with are cracking and flaking off.

Dirtyd0g
05-01-2011, 03:24 PM
Have you ever tried to coat the plastic 4.6 2v valve covers? Can it be done with low heat? Or does it need the liquid coating?

If you need a set to test I have a half dozen I could spare one. I think they would handle 250° as the engine runs pretty close to that without damaging them at all. I always see the caps destroyed by the heat but the valve covers look ok.
Alan

BLOWN38
05-01-2011, 07:56 PM
If you need a set to test I have a half dozen I could spare one. I think they would handle 250° as the engine runs pretty close to that without damaging them at all. I always see the caps destroyed by the heat but the valve covers look ok.
Alan

I'll take you up on that offer. Pick em up from you when I'm in ohio next if you are there too. If not i'll get you paid for shipping.

nliberto@powder
05-02-2011, 09:11 AM
Hmmmm Best powder type for wheel applications. Not a stump question. Just seems allot of coaters I run into dont seem to understand the different types so much

Good Question!

The generic formulas of powder coating are as follows:

Epoxy = Great chemical resistance & toughness but no UV (sunlight) resistance. This is used for most underhood & undercarriage automotive parts. Forget using this for wheels. :p

Polyester = Good chemical resistance & toughness with very good UV resistance. Available in urethane, TGIC, and a few lesser known flavors. This coating is most often used for automotive trim parts. TGIC is the best candidate for one-coat powder application on wheels. :)

Acrylic = Good chemical resistance and superior UV resistance, however very poor mechanical properties (very hard and brittle). Available in urethane and GMA flavors. This coating is used by the OEM wheel manufacturers for clear and color coatings. :D

The best coating solution is to use TGIC polyester powder as a color base coat and topcoat with GMA acrylic clear powder. This approach allows for the better mechanical properties of the polyester with the hardness and superior UV resistance of GMA acrylic. :cool:

However, many powder coaters do not spray acrylics, as they can contaminate thier system and cause problems when they use polyesters if they do not clean their equipment properly. This is why some people will spray this stuff in a completely isolated process in a different room. :eek:

nliberto@powder
05-02-2011, 09:14 AM
Good one. Cause the stuff mine where done with are cracking and flaking off.

Sounds like maybe the coater used acrylic powder in a single coat process.:eek:

Either that, of they poorly prepared the wheel before coating it.:(

Now you have no choice but to strip the wheel completely clean and recoat it again. I'd be pissed if this cracking showed up after less than 5 years of use! :mad:

nliberto@powder
05-02-2011, 09:20 AM
I'll take you up on that offer. Pick em up from you when I'm in ohio next if you are there too. If not i'll get you paid for shipping.

Sounds like we have the tools to conduct an intersting experiment!:cool:

Problem is, most powder coaters do not understand the proper way to powder coat plastic parts.:(

Tell the coater to clean the surface very well before coating. Then they need to lightly scuff the surface for proper adhesion. Finally, they need to select a low-temperature cure powder coating and cure it for the longer time at the lowest possible cure temperature (up to 60 minutes at 250 degrees F).

Unfortunately, they will probably want to rush the cure process (time is money) by using a higher temperature (30 minutes at 325 degrees F). This temperature may distort the plastic valve cover. :(

BLOWN38
05-02-2011, 03:13 PM
Sounds like maybe the coater used acrylic powder in a single coat process.:eek:

Either that, of they poorly prepared the wheel before coating it.:(

Now you have no choice but to strip the wheel completely clean and recoat it again. I'd be pissed if this cracking showed up after less than 5 years of use! :mad:

Less than a year for me.:mad: The rears are holding up better. One front is terrible. I'll get some pics.

XxSlowpokexX
05-02-2011, 03:35 PM
Less than a year for me.:mad: The rears are holding up better. One front is terrible. I'll get some pics.

Well if you ever get an urge to release those poor powdercoat cracking wheels.....Let me know;O)

XxSlowpokexX
08-02-2011, 01:56 PM
I was curious if you know of a local to NYC who could do a proper job refinishing wheels including plastic centercaps.
:eek:

nliberto@powder
08-02-2011, 03:11 PM
I was curious if you know of a local to NYC who could do a proper job refinishing wheels including plastic centercaps.
:eek:

See a previous post:

"For future reference, go to www.powdercoating.org (the Powder Coating Institute) www.pcoating.com (Powder Coating Magazine), and www.pfonline.com (Products Finishing Magazine) as they all have a list of "job shops" or "custom coaters" by geographical area. Some of these sites even describe the type of work they do or the size parts they can handle. Stay away from the high production shops and you will get good service."

Unfortunately, I do not have first hand experience that would be helpful to you.

XxSlowpokexX
08-02-2011, 03:35 PM
Thanks Nick..I just hate trusting anyone I dont know when it comes to work quality!

Miller
08-02-2011, 04:53 PM
i know a guy with a bunch of extra rims. just sayin

nliberto@powder
09-05-2013, 10:50 AM
Bump. Anyone want to play "Stump the Consultant"????

BLOWN38
09-05-2013, 11:58 AM
What can I top coat this chrome powder with so it doesn't oxidize? And a clear powder turns the chrome powder to silver. I also tried some shark hide Sharkhide link (http://www.eastwood.com/sharkhide-aluminum-protectant-quart.html) but that turned it silver too. Shark hide worked great on the blower itself.

Maybe a good catalyzed clear paint. 2K paint (http://i169.photobucket.com/albums/u216/blown38/20130329_124154_zpsb5a4135a.jpg)

Coolant crossover tube is the powdered part. Goes under the blower snout.

http://i169.photobucket.com/albums/u216/blown38/20130329_124154_zpsb5a4135a.jpg

Edit... looks like I already asked the question somewhat. Maybe there is another non powder coating that you can recommend. Or maybe you can coat a part with some chrome take a pic then clear it with powder and take a pic. To see if the pro can do better.:)

XxSlowpokexX
09-05-2013, 02:46 PM
Question. How do we prevent the oxidation of something aluminum that has already been powdercoated. Is it a prep issue? Ive had issues over time with brackets and various other engine componants that have oxidised under the powdercoat itself. No chips or scratches:O)

BLOWN38
09-05-2013, 03:48 PM
I would think it wasn't prepped well.

nliberto@powder
09-05-2013, 04:10 PM
Chrome "look a like" powder coatings are formulated using highly reflective pigments. Unfortunately, these coating will begin to "tarnish" or dull if not protected when exposed to different atmospheric conditions. This is a form of oxidation, but not in the sense of rusting or aluminum oxidization.

Normally the powder coater will apply a thin-film (< 2.0 mils) of clear powder to protect this chrome look a like powder base coat. However, if the clear coating is applied too thick or cured in an improperly exhausted (not enough air) oven, then the coating clarity can be compromised.:eek:

Another lower risk approach is to use a 2k or 1k liquid clear coating. These coating are applied in very thin film thicknesses (< 0.8 mils) and are "air dried" or catalyzed (for 2k materials). This eliminates the two problem I discussed above: inadequate oven ventilation and a too thick clear coating. The results of this combination should provide you the clarity and depth of finish you desire.:D

Nice motor by the way. Some day you can tell me how to wedge a blown V8 into my 1989 SC.:)

nliberto@powder
09-05-2013, 04:23 PM
Question. How do we prevent the oxidation of something aluminum that has already been powdercoated. Is it a prep issue? Ive had issues over time with brackets and various other engine componants that have oxidised under the powdercoat itself. No chips or scratches:O)

Powder Coatings, like any other paint job, is only as good as the surface it is applied to. Proper surface preparation and pretreatment is a must if you want to have a long-lasting coating.

Any surface must be cleaned of organic soils (oils, waxes, hand prints, chlorides and salts, etc.) and inorganic soils (rust, oxidation, laser scale, etc.) prior to coating. The methods to do this important cleaning step can also cause problems if not executed properly. For instance, if you use solvents to clean the oils from a part there may be residue left on the surface that will volatize or gas during powder cure. Well water often has hardness issues and chlorides and sulfates that will cause premature corrosion on a part, as well.

After the cleaning step, a pretreatment conversion coating will prepare the surface for good adhesion and better corrosion resistance. Popular conversion coatings are Iron Phosphate, Zinc Phosphate, and Zirconium for ferrous based metals and Chromate Conversion Coatings for aluminum.

I am also attaching an article I wrote some time ago in Powder Coating Magazine for your reference. It discusses expected product life for different combinations of substrate, pretreatment, primers, and topcoats. This article is available on our website www.powdercc.com along with many others, Most all are downloadable for free. This corrosion article in available for $4.95, but I just gave it away here to any SCCoA member who cares to look at it.

BLOWN38
09-05-2013, 06:26 PM
Nice motor by the way. Some day you can tell me how to wedge a blown V8 into my 1989 SC.:)

I actually had planned to put a motor similar to that in a bird. But time and money prevented that. That motor will fit between the shock towers of a bird.;)

davec73
09-05-2013, 06:41 PM
Ive tried multiple different types of automotive clear in thin layers over the chrome powder with the same result. However aluminum seems to react the worse to clear coat over the chrome powder. Until someone develops chromes that don't mar I will go color with everything.

nliberto@powder
09-06-2013, 09:00 AM
Ive tried multiple different types of automotive clear in thin layers over the chrome powder with the same result. However aluminum seems to react the worse to clear coat over the chrome powder. Until someone develops chromes that don't mar I will go color with everything.

Chrome powder coatings are not formulated for very good mechanical properties (like mar resistance, hardness, etc.). They are formulated for high reflectivity. This is why the clear topcoat is typically applied.

Having said that, clear topcoats will often slightly reduce the chrome reflectivity. To what degree this happens depends upon the coating used, the coating thickness, and outside influences (oven temperature and exhaust rate).

The only thing that looks and works like chrome is another metal-based technology (i.e. paint is paint and metal is metal). The most popular "cross-over" chrome or plating substitute technology is Vapor Deposition Coatings. Parts (often plastic) are pre-coated with a very smooth powder coating and placed into a vacuum chamber. A plasma is created in the chamber that deposits the metal onto the part. The result is a highly reflective durable coating. This method is used to create the reflectors on headlamps, plumbing fixtures, and many other "plated" products. I am not an expert in this technology, but have seen it and supported the powder coatings part of it in the past. Search online for this technology for more information.

peagnit2
09-08-2013, 12:02 PM
I had to replace the rear leaf spring hangers on my brothers Ranger a few years ago and it seemed to me that any breach of the coating allowed rust formation, and since the coating was so tough and durable that it stayed more or less intact, in near proximal relation to the substrate hanger. This in turn created water traps that where worse than if a protective coating where allowed to slough off.

Those Ranger hangers where literally corroded in two.

Is my analysis correct or am I pissing up a hanger?

nliberto@powder
09-09-2013, 02:46 PM
I had to replace the rear leaf spring hangers on my brothers Ranger a few years ago and it seemed to me that any breach of the coating allowed rust formation, and since the coating was so tough and durable that it stayed more or less intact, in near proximal relation to the substrate hanger. This in turn created water traps that where worse than if a protective coating where allowed to slough off.

Those Ranger hangers where literally corroded in two.

Is my analysis correct or am I pissing up a hanger?

The coating failure you describe is called a "Creep" failure, whereby the coating is cut to the substrate and the corrosion that sets in at that point under-films the adjacent coating. This type of failure is the most severe in terms of "time to failure" (fastest failure). The above article describes this failure very thoroughly.

I am afraid that the speed to metal failure would be unaffected by trapped moisture, as you describe, than if the coating would have been completely missing (sloughed off). The fact the metal substrate was exposed in itself would have caused your metal failure in the same time. Furthermore, any moisture trapped between the coating and the substrate would probably evaporate it a short time anyways. Finally, any loose coating provides no more or less corrosion resistance to the underlying substrate, as it is no longer considered a corrosion barrier at that point.

Generally, any area that is absent of coating will corrode quickly. Time to metal failure is dependent upon the metal thickness and the metal alloy.

peagnit2
09-10-2013, 05:12 PM
I am intense.

Excellent answers and rubutals!

Sounds good to me.

nliberto@powder
02-27-2014, 06:13 PM
Hi Y'all:

It has been some time since I checked the SCCoA Forum out. Nice new look.

Anyways, I am back on the job to answer your Powder Coating Questions. Play stump the Consultant.

XxSlowpokexX
02-27-2014, 11:01 PM
Question #1 CArlisle?
Question #2 Best type of powdercoat for underhood?

Also any way to prevent oxidation of aluminum under teh powder?

nliberto@powder
02-28-2014, 01:33 PM
1. The only way I will go to Carlisle is to trailer my car. I just is not worth the risk to drive that far and risk a road hazard incident that will take out my Coddington wheels. I decided this last year and it is especially applicable this year with the tough winter and all the potholes. I looked into buying an enclosed trailer, but have difficulty justifying it for a once a year use and can't figure where I would store it. I even looked at renting an open trailer, but this has issues as well. Having said that, I hope to possible find a resolution to my indecision soon.

2. Under-hood parts are normally coated using pure epoxy or epoxy-polyester hybrids, as they offer the best chemical resistance and are very tough coatings. Color selection is extensive in these formulas, except in clears and tinted clears. These coating have poor UV (sunlight) resistance and can chalk (loss of gloss) in direct sunlight in a couple of weeks. The chalk can be easily removed using a cleaner wax, compound, or even a dry cloth if it isn't too bad. However, this normally doe not present a problem for under-hoop and under-carriage (chassis) applications.

3. All metals oxidize when exposed to air (oxygen). Moisture and salt accelerate the time of occurrence and the degree of this oxidation. Coatings (powder or liquid paints) will slow this process, but not eliminate it entirely. Better coatings. like powder, will slow this process more than other coatings. Cleaning parts before coating will eliminate contaminants that will accelerate the oxidation process. Converting the metal surface using a pretreatment will enhance adhesion and significantly improve corrosion (oxidation) resistance. Aluminum is protected best with a chromate conversion pretreatment, but can also be converted using zirconium pretreatments.

If you want to get "real technical" look at the attached article.

XxSlowpokexX
02-28-2014, 06:30 PM
1. The only way I will go to Carlisle is to trailer my car. I just is not worth the risk to drive that far and risk a road hazard incident that will take out my Coddington wheels. I decided this last year and it is especially applicable this year with the tough winter and all the potholes. I looked into buying an enclosed trailer, but have difficulty justifying it for a once a year use and can't figure where I would store it. I even looked at renting an open trailer, but this has issues as well. Having said that, I hope to possible find a resolution to my indecision soon.

2. Under-hood parts are normally coated using pure epoxy or epoxy-polyester hybrids, as they offer the best chemical resistance and are very tough coatings. Color selection is extensive in these formulas, except in clears and tinted clears. These coating have poor UV (sunlight) resistance and can chalk (loss of gloss) in direct sunlight in a couple of weeks. The chalk can be easily removed using a cleaner wax, compound, or even a dry cloth if it isn't too bad. However, this normally doe not present a problem for under-hoop and under-carriage (chassis) applications.

3. All metals oxidize when exposed to air (oxygen). Moisture and salt accelerate the time of occurrence and the degree of this oxidation. Coatings (powder or liquid paints) will slow this process, but not eliminate it entirely. Better coatings. like powder, will slow this process more than other coatings. Cleaning parts before coating will eliminate contaminants that will accelerate the oxidation process. Converting the metal surface using a pretreatment will enhance adhesion and significantly improve corrosion (oxidation) resistance. Aluminum is protected best with a chromate conversion pretreatment, but can also be converted using zirconium pretreatments.

If you want to get "real technical" look at the attached article.

Ohh I am familiar with treatments of metals and why they corrode. Just wasnt sure what processes would be used with powdercoating and still get good adhesion. Had an issue with an intake or two after 10 plus years..Seems teh prep is better then some....But I douubt they use a pretreatment. Is there a particular product?

nliberto@powder
02-28-2014, 07:05 PM
Ten years!!! What do you want, "FOREVER"? :D

The best powder coating job on chromated aluminum (outdoor furniture) is warranted for 15 to 18 years. Skyscrapers use coatings (Kynar & Duranar) that can last 30 years when applied on aluminum with the same chromate pretreatments.

Chromate conversion coatings and zirconium conversion coating are sold by Pretreatment Chemical Suppliers like DuBois, Henkel, Chemetall, Coral, and about a dozen more. These guys sell directly to the Custom Coater (Job Shop) companies and OEMs. You will not be able to buy from them though. That is why Eastman has a selection of pretreatment chemicals for the hobby powder coater.

If you clean the surface really well and remove the oxides, you should get at the 10 years you experienced on aluminum and about half that on steel.

XxSlowpokexX
03-01-2014, 11:01 PM
Ill have to check out eastwood. Its funny because I do alot of forensic work with curtain walls and failure of finishes. I always have you in mind if we ever need a coatinsg expert but it never comes to that:O)



Ten years!!! What do you want, "FOREVER"? :D

The best powder coating job on chromated aluminum (outdoor furniture) is warranted for 15 to 18 years. Skyscrapers use coatings (Kynar & Duranar) that can last 30 years when applied on aluminum with the same chromate pretreatments.

Chromate conversion coatings and zirconium conversion coating are sold by Pretreatment Chemical Suppliers like DuBois, Henkel, Chemetall, Coral, and about a dozen more. These guys sell directly to the Custom Coater (Job Shop) companies and OEMs. You will not be able to buy from them though. That is why Eastman has a selection of pretreatment chemicals for the hobby powder coater.

If you clean the surface really well and remove the oxides, you should get at the 10 years you experienced on aluminum and about half that on steel.

nliberto@powder
03-03-2014, 07:30 PM
Ill have to check out eastwood. Its funny because I do alot of forensic work with curtain walls and failure of finishes. I always have you in mind if we ever need a coatinsg expert but it never comes to that:O)

Well there is always hope for the future. We can use the business!

XxSlowpokexX
01-19-2015, 12:24 AM
Nick..Having a buddy who owns a PC shop give you a shout. Name is Keith. Hes new to it so he has some questions:O)

nliberto@powder
01-19-2015, 08:53 AM
I look forward to it. Have him mention SCCoA for context.

Thanks,