I have some questions in regards to powder coatings. I am interested in getting some parts powder coated and my questions are geared towards CudaChick.
Hi blackace! I'm always happy to answer questions but it's a lot easier to do so if I know they're here. LOL Sorry for the delay; I didn't see your thread until just now. For future reference, I don't get on the board every day so please send me a PM if you have follow ups and want a fast response.
I know it's supposed to be a durable coating but,
Are powder coatings resistant to chemicals?
For the most part, powder coatings are resistant to most automotive chemicals but you wouldn't want to soak your parts in them, just like you wouldn't soak painted parts in them and expect your paint to still look good.
Non-silicone based brake fluids [i.e., any that
aren't labeled "DOT 5"], brake cleaners, carb cleaners and battery acids are all harsh chemicals that can theoretically harm cured powder if left to sit on powder coated parts. Sure, accidental spills happen now and then, but if it's cleaned up fairly quickly, it should not leave any lasting ill effects.
I've heard 'horror' stories over the years just like you have. Usually harsh chemicals will only dull a glossy finish, not completely remove them down to bare metal. Even chemicals specifically designed to remove tough finishes (like aircraft stripper or Paint & Powder Coating Remover) take a long time to work and aren't always effective.
For what it's worth, I TRIED to damage a little scrap coated piece as an experiment by leaving it in some nasty old Dot 3 brake fluid for a week. It didn't do a thing.
Is powder coating scratch resistant or scratch proof?
No finish is "scratch proof." But when the part is properly prepped and the powder is applied and cured per the manufacturer's instructions, it's a LOT tougher, lasts longer and is available in more colors and textures than paint. It
can be marred or chipped if you hit it hard enough though.
Not usually. But make sure your coater uses a powder that's UV stable (or sealed with a clear powder) if the part will be subjected to sunlight and/or the environment. Most powders for automotive use are already UV stable.
Powders are developed by where they're going to be used. Some are strictly for indoor applications, heavy use items (like outside hand railings), decorative items, automotive applications, industrial uses, etc. Epoxies and hybrids are generally not recommended for automotive use.
Some metallic-based powders require a clear coat to seal the finish because those powders actually have metal particles in them and can oxidize over time, requiring occasional polishing just like real metal does. Well, because it IS real metal. :-D
Certain clear coats can yellow too, but that is usually only when they're not applied and/or cured properly. Clears are touchy to work with.
Not sure if this is correct but I thought I read somewhere that it is a plastic in the form of a powder, is that correct?
Powders are comprised of many different ingredients but are generally urethane, polyurethane, polyester, acrylic or epoxy-based, or some hybrid combination of the above. Some are compatible with each other and some are not. So yes, they are basically made out of plastic.
How thick of a coating is normally applied?
It's only a few mils thick. Pro coaters use thickness gauges to make sure the coating is within normal tolerances for that particular powder / application. Factory logos and defects in the metal will NOT be filled in by powders in such a fashion as to completely obliterate them -- they'll still show up.
I know that it is backed on but can it be applied over body filler and will it have any issues?
No, I wouldn't recommend even trying to powder coat Bondo because it's not metal and the powder would have nothing to stick to.
Without addressing scientific explanations of the various types of powder guns out there, powder coatings are applied electrostatically, meaning the part itself is attached to a ground clip and the gun charges the powder with the opposite polarity so the powder is actually attracted to the part being powder coated. Kind of like how your magnetic retrieval tool grabs that bolt you dropped in the valley pan, but it also wants to grab all the other metal in the area.
Thank you for your questions and a really great, down-to-earth post! Don't ever hesitate to ask when you have more. That's what I'm here for. :love7:
