nliberto@powder
SCCoA Member
Powder Coating Answers
Ok, smart a##. here goes:
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!
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.
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?
Ok, smart a##. here goes:
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!
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.
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?
