Baked on Enamal Spray Paint

As far as enamel paint and baking, it does make the paint cure faster. However, what you end up with is not baked enamel. The term baked enamel is used when talking about the baked ceramic (or porcelain) finish used on appliances and bathtubs.

As far as the water treatment goes, it does work... Enamel dries by solvent evaporation and cures by oxidation (or cross-linking if a hardener is used). Water speeds oxidation. Just like with iron and rust.

Heating the enamel helps dry the solvents and speeds the reaction time for curing. In some cases, if the humidity was too high when the paint was applied, or if it was applied too thickly, it may be weeks to get full cure. This is because the outer layer of paint is cured, but inside it's sealed off from the air. Solvents can't get out and oxygen can't get in. B

Baking can help with this sometimes by allowing the solvents inside to escape... Why? The vapor pressure of the solvents is increased at high temperatures and the outer layer softens and the solvents can get out.

Baking works well, but don't rush it. Heating the curing paint too soon can cause bubbling (solvent pop), loss of gloss, smoothness issues, etc.

John
As far as enamel paint and baking, it does make the paint cure faster. However, what you end up with is not baked enamel. The term baked enamel is used when talking about the baked ceramic (or porcelain) finish used on appliances and bathtubs.

As far as the water treatment goes, it does work... Enamel dries by solvent evaporation and cures by oxidation (or cross-linking if a hardener is used). Water speeds oxidation. Just like with iron and rust.

Heating the enamel helps dry the solvents and speeds the reaction time for curing. In some cases, if the humidity was too high when the paint was applied, or if it was applied too thickly, it may be weeks to get full cure. This is because the outer layer of paint is cured, but inside it's sealed off from the air. Solvents can't get out and oxygen can't get in. B

Baking can help with this sometimes by allowing the solvents inside to escape... Why? The vapor pressure of the solvents is increased at high temperatures and the outer layer softens and the solvents can get out.

Baking works well, but don't rush it. Heating the curing paint too soon can cause bubbling (solvent pop), loss of gloss, smoothness issues, etc.

John
 
The old timers in the body shop when I was a kid used to soak the paint with a gentle flow out of a hose the next day. They would do that for about 15 minutes to 1/2 hr.
 
I've gotten into the habit of curing rattle can paint with a heat gun after it flashes off. Best for enamels. I like engine enamel for durable things in the shop; it becomes a different finish after heat is applied.
 
I have recently paint-n-baked a number of components using rustoleum spray paint. It gets quite hard after a few hours at 200*F max. I am pleased with it. Preheating your parts also helps. I don't think it is power coat or machine paint quality, but that is fine for what I do.
 
I sent a question to Rust-Oleum Product Support several years ago:
Are general spray paints improved in curing time or hardness by baking? I'm not referring to your High Temp consumer spray can paints. If so, what times and temperatures are recommended?

Their response:
Thank you for contacting Rust-Oleum Product Support. We appreciate your interest in Rust-Oleum coatings. For our aerosols, they fully cure in 7 days. "Baking" them high temperatures would not be recommended for paints other than the High Heat. I hope this information is helpful to you and wish you luck on your project.

I still find heat curing ( ~200°F) rattle can painted parts greatly improver the curing time and toughness.


Ken
 
In good weather when the sun is out I've used RustOleum brush enamel and gotten good results. And it's inexpensive.
Couple hours in the sun and it dries hard. I like their spray primers too. I used to be a Krylon guy but I switched.
Mark
 
I'll bet Rustoleum says that because people think baking means the oven in the kitchen at 350 about 15 minute after spraying. I've redone a fair amount of lantern founts and a bake in a large toaster oven under 200 works quite well, especially when the shop is cold. Quite anxious to try the water thing.
 
I've had great results with Duplicolor engine enamel. After the paint has dried, I bake in an oven at 250 degrees f. For two hours. The paint cures very hard and glossy.
 
Here in Texas, you just paint something and leave it out in the sun for the rest of the day. The following morning the paint is rock hard. Just don't try to paint something already hot in the sun.
Randy
 
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