Baking Enamel Paint?

[Devin]

I know that when pro's paint metal items, they bake them in an oven to get them super tough.

Has anyone ever tried this with a model piece (cast metal, of course). I'm getting ready to re-paint some diecast metal tow trucks for a customer, and I'd really like to be able to bake it in the home over if it's at all possible, to really set the stuff hard.

Does this require special paint? What oven settings? I'm assuming very low heat for a long period of time.

Thanks for any info,

-Devin

[Shinnentai]

Does this require special paint?

Yes. Typically it is applied in powdered form, and melts/fuses into a paintlike finish when baked.

What oven settings? I'm assuming very low heat for a long period of time.

Very intense heat for relatively short periods actually. You'd need a kiln, not an oven.

It's doable as a garage technique, but it takes finesse, and a large startup cost (a suitable small electric kiln will run you around $400). If you're still interested, check with your local college campuses for jewelrymaking programs.

[Devin]

Does this require special paint?

Yes. Typically it is applied in powdered form, and melts/fuses into a paintlike finish when baked.

Actually the powder form is called Powder Coat, a different process. I know it can be done with liquid enamel paint, because I've seen it done by guys who paint motorcycles, helmets, etc. in the past. Never thought to ask them if they were using anything beyond regular automotive enamals, though.

-Devin

[d_coombes]

Model car guys often use a food dehydrator with the racks cut out for speeding up enamel paint drying.... I had one for a while when I was into the masochism of painting model cars..... I'm over that now!

Here is something similar
http://www.ninfinger.org/~sven/models/tools/dryer.html

You have to be a bit careful with plastic parts as you don't want them to distort from the heat.
Cheers
Dave

[Shinnentai]

Actually the powder form is called Powder Coat, a different process.

I know, but I wasn't talking about powder coating. Powder coating is a relatively recent (1960's) industrial offshoot of the baked enamel process, and is a bit different in procedure and chemistry. Baked enamel is a decorative method that goes back hundreds of years, and is still used for durable finishes on metal subjects.

It can be done with enamels in a liquid carrier, but if you've seen it being done with a regular type oven (or on a plastic or composite subject), it was likely a post-cure or speed-cure process. Actual "baked enamel" finishes require temperatures a little closer to those used for glasswork or ceramics than for food. You might be able to use an autoclave for some types, but not an ordinary oven.

[TER-OR]

Modern auto paints are not the same as those used some time ago. To limit the amount of volatile organic compounds (VOCs) in the air, new paints were developed. So, instead of lots of ugly things like toluene and xylene we now have baked-on automotive paints.

The hobby industry still uses the solvent-laden paints.

I don't know whether there is an equivalent hobby system.

[d_coombes]

A lot of the modern paints are of the 2 pack catalysed variety and can't be sprayed without proper filtration because they are poisonous so they are out for hobby use!

That said you might be able to convince a body shop or a bike customizer in your area to paint them for you....

Without a food dehydrator gloss testors enamels take about 3 weeks to gas out properly... a food dehydrator takes about a week, the they are ready for polishing.

Dave