Hot Rods frame powder coat or paint question

powder coat is no different than paint-bad prep=bad longevity. i have some wire wheels i blasted, epoxy primed, and acrylic enamel painted 25 years ago that really look good yet besides a few chips from living on a gravel road. then, a while back our mechanic at work told me they have a place that will blast and powder coat truck wheels for 35 bucks, pickup wheels for 25 bucks. well, i can not even buy the materials for that, so i had 4 wheels done for my pickup. 6 months and they were rusty as hell and i dont drive it in the winter. minimum wage kid doing the blasting i would guess

 

That's what I was worried about. I have several places o my frame that are pitted, but not bad enough to require repair. If I paint with a single stage urethane, I can float a little filler in there and not lose any sleep over it. But, with powder, it will require more labor. Just my take from here...

 

Most of the frames I see powder coated are new frames.
I plan on blasting mine, industrial epoxy and or POR 15 urethane

 

You can do that with powder coating too.

Lab Metal filler takes powder coating just fine.

 

I restored a baptistery for a church around 6 years ago. This particular church keeps it full 24/7. The deacon in charge of the project said they stay “ready to baptize at any moment”
I did a lot of research on what paint to use.
Water proof and submersion proof are different things.
The POR 15 “white coat”was recommended by a friend. I checked into it. Product was recommend for boats, bathtubs, porcelain restoration .....
The guy that recommended it uses it on his machine equipment. This stuff stays wet with coolant and covered in shavings. Seems to be very chemical resistant and has held up well to the abuse his lathe and mill have give it.
I repainted the baptistery according to the instructions. (It’s very humidity sensitive).
6 years of continued submersion in salt water(the church uses a salt water system) and the baptistery still looks great.
I think my next chassis will be sprayed with this.

 

My frame is powder coated but of course it was a new built frame with no grease and no filler was used. Now, if you're going to use filler, then you can't powder coat because the oven will burn the filler off and the powder wouldn't stick to it anyway.

 

PM me and I'll send you some filler for your pitting and you can powder coat over it

 

At the end of the day, whether you choose powder or paint will depend on which is more important to you; appearance or durability. Properly applied powder is the durability champ, hands down. But for appearance, paint gives you far more options, particularly if you're dealing with old rusty bits. One place that powder beats paint every time is aluminum parts. It can be tough to get paint to stay on aluminum over time, powdercoat over a properly-prepped surface then just try to get it off. Also the best stuff I've found for battery trays if you do at least three coats.

I've been powdercoating smaller parts at home for about 15 years now. The set-up is fairly cheap; you can buy a decent gun for less than $100 these days, add a blast cabinet and a used household oven (free or cheap off CL) and you're good to go. I had my share of miscues when I started but it's now my go-to for chassis/underhood parts, normally not seen brackets and the like on cars. I can coat almost every part that fits in my oven on a motorcycle in a solid color for about $20, far cheaper than paint. If you stick to black and buy in bulk, you can get the price down even more. 90+% of the cost of coating is the tools/labor.

It's the larger parts that you have to take to a commercial coater that cause issues. These guys just want to blast and coat; if you can find one that will fix imperfections or do something 'special', expect a sharp rise in cost. Doing filler before you take it in is generally useless as the blaster can't really see the filler while working and will probably just blast it off. Because I control the whole process at home, I can do a better job than them as well as do it cheaper.

 

Lab Metal.

 

I tried that, it didn't seem to work any better than J-B Weld... Expensive too...

 

The only filler I have used for powder or porcelain is metal. Replace the bad or weld it up.
The porcelain process didn’t like silicon bronze.
I dont remember an issue with powder coat.

 

Strange. I have been using it for years, without issue.

 

I was trying to fill unused holes in aluminum, neither that or J-B Weld worked well. The lab metal was marginally better than J-B Weld for thin applications but given the price, not that much better.... LOL

 

I’d just clean it and paint it and call it a day.
But I never worried about crawling under it to touch it up

 

What if you decide to change the color, down the road someday. How do you get powder coat off?

 

You can sand it and paint it.

It is not impervious to certain chemical strippers.

 

We painted lots of powder coated pieces.
Clean,sand, clean and spray

 

You can coat over existing powder if you pre-heat the part to about 200 degrees.

 

We did an experiment with Lab Metal 18 years ago. Top notch powder guy. It ALWAYS ghosted through where we used the LM

 

You have already received so many replies that mine probably won't help, but here it goes: I have had all of my 55 T-bird suspension, steering, and rear axle assembly powder coated. Everything looks great, but it doesn't seem to be any more durable than spray paint. I live in California, where EPA standards limit the products that can be used. I've been told that powder coating used to be far more durable than what's available today. If you can achieve the same appearance with either powder coat or spray paint, I would choose the more affordable of the two, as long as the shop that performs the work is reputable and will provide at least a 1-year warranty.

 

@55blacktie, i am no expert on powder coat, just the one experience. my point was the prep, not the product. i dont think the product has gotten worse, but again its all about bare clean metal for anything to bond. another thing not mentioned in this post yet, unless i missed it, is that often the cheaper powder coat jobs are done over bare steel, no primer. in that case, when you get a chip or a scratch its down to bare metal and it starts to rust that day. with paint, you have a chance that the chip only took off the paint, leaving the primer, so it could be touched up, or if epoxy primed will not rust. i am told that now days the better powder coat places do do it in two coats, prime, and color, so in theory that would wipe out my rust thoughts. the cost of good paint has gone crazy the last decade or so, and you being in cal makes it even harder from what i understand. i still do my own paint, but now days even though i have a big portable compressor, i can not buy sand and fuel it up for what my blaster guy charges since he is working with bulk material, and i buy sand by the bag

 

Did you use powder coat primer first? I have literally never had that happen.

Maybe they improved the formula in the last 18-years.

 

Lab Metal has not changed in decades

 

I guess I'm just lucky then.

 

After reading some of the negative replies, I've come to the conclusion that some applicators simply aren't putting on enough powder. You can get a very good cosmetic appearance with as little as 2 mils thickness but at that thickness it's ability to withstand flying debris is no better than paint and maybe not even that good, and 'fully sealed' coverage may not be adequate. There are different thickness recommendations depending on intended use and the final appearance desired. Thicker coating tends to obscure surface detail, which can be either a plus or minus depending on the 'look' you're after. And just like paint, the 'tooth' the base surface has will affect how well the powder will 'stick'. For best adhesion, powder likes a considerably 'rougher' surface compared to paint which is why sandblasting is widely used. The failures that some report on 'commercial' coating jobs is the lack of this tooth as most don't sandblast but just coat over the mill finish. To get a glossy or smooth finish, apply more powder; it's self-leveling will smooth the finish.

I shoot for at least a 10 mil thickness; thicker is better. I'll apply the powder until I don't see any more build-up on the part, not just enough to cover. I've never had any issues with runs on a initial coat (that's the idiot-proof part of coating... LOL) and generally end up with a 15-20 mil thickness. Unlike paint, thick is good. Rather than making it more prone to chipping, it reduces it. Powdercoat is much 'softer' compared to paint which is why it resists chipping so well if applied right. In effect, it 'pads' the surface. I use a 'rule of thumb' test to see if the coating is thick enough; if I can press a fingernail into the coating and leave a small temporary impression, I've got enough thickness for durability. With a bit of experience you'll be able to tell from just looking.

For extreme applications like battery trays, I'll re-coat several times. Now once the part is coated the electrostatic attraction no longer works very well, so by pre-heating the part to about 200 degrees the powder will partially melt on contact and stick. You do have to pay attention when doing this as it is possible to get runs but not nearly as easily as you might think; you need to make sure you apply enough so you don't get orange peel. A bit of practice will show you what works. I try for a 40-50 mil thickness on these for a rust and corrosion-proof tray.

One disadvantage to powdercoat (shared with paint to a degree) is if you have parts that go together with close tolerances, the added thickness can interfere. You can either mask before coating or remove the coating where needed afterwards. Masking with tape presents issues as you need special high-heat tape ($$; if you want an entertaining afternoon, try scraping baked-on regular masking tape off...) and if you're not doing the coating you'll be paying somebody else to do it (more $$). I'll fabricate metal 'masks' where needed that will withstand blasting, so the coater can just blast and coat. That reduces costs considerably; I've had several motorcycle frames done, this cut the cost in half. The second option is remove what you need to after coating (Scotchbrite discs work well) but this can be difficult. Accessible threaded holes can be chased with a tap, or a sacrificial bolt installed.

Roothawg pointed out another disadvantage of powdercoat; it does 'micro-scratch' easily. The surface, being softer than paint, it doesn't take much and over time it will tend to dull a bit. The local guy I use for the larger items addresses this with a urethane clear coat. The clearcoat will chip, but without breaching the base color. As to 'priming' under the finish coat, I don't get that at all. Unless you're using a multi-step specialty coating or a translucent/transparent coating, adequate thickness should be all you need. Somebody may be running up the cost....

 

To get back to the original question, if you're having a frame done you'll almost certainly be dealing with a commercial coater.

So the questions you need to ask yourself are:

How important is cost? Coating will surely be more unless you go with a specialty paint or are having it painted by someone.
How important is appearance? Paint is better (in most cases) than powder here and certainly superior if after-the-fact, cosmetically-acceptable modifications are needed.
How important is durability? Properly-done coating is the winner here, no question.

And the questions you need to ask the coater:

How thick is the applied coating? I would consider 10 mils as the absolute minimum, 20 would be much better. And will they guarantee a minimum thickness? I would suggest miking the frame in various places prior to coating then checking afterwards. And tell them you've done this if you don't know their work.

What can you do to make the coaters job easier? The less work he has to do, the less it will cost. Keeping in mind that any good coater will blast the entire piece to insure that they have a known good surface to coat to, any pre-prep you can do that can reduce the time to do that will help lower costs. Minimize or eliminate any masking requirements or pre-mask with metal.

 

10 mills is a lot of material.
We would use thin washers when welding suspension brackets and for anything that was welded to the chassis that parts bolted to, especially in double shear.
That’s was so when the chassis came back from powder coating or paint, we didn’t have to scrape material off for parts to fit.

 

Yes it is, but at $11 lb retail for basic black it's the smallest cost part of the job. Less if buying in bulk. 1 lb of material will coat a lot of small parts and even something as large as a frame can be done with 3 lbs or less. And the nice thing about powder is it doesn't go bad as long as you keep it dry.

 

Like @Crazy Steve say, paint is the smallest cost of the job.
We payed 6 dollar lb for basic black /white powder coat in 44lb box.
If you want the best quality/rust resistant,,,,,,,
Blasting,Primer,Paint or Powder,Clear Coat.
Whether it is powder or paint.
If the powder coat is coming of in flakes,,,,,bad prep,
wrong type of powder (there is indoor/outdoor type) or poorly cured.
For us 7 mills was the minimum when it comes to
rust resistant.