D

dspender

Well Known Member
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Not sure which forum to place my question, which is this; For welded steel tubular structures, such as engine mounts, brake pedals, throttle sticks, cabin framing, etc.
1) Is there a durability advantage for powder coating vs 2-part epoxy primer/paint?
2) Is the price differential significant, or similar between the two?

I can prep and spray a 2-part epoxy primer and paint, but I would need to take the items to a shop for powder coating.

What is your opinion?
 
I ordered canopy weldments and roll bar bare. They were fit then powder coated before final install. Stick weldments were left white so cracks would be visible. The portion that shows above the boot powder coated.
Motor mount and gear towers were not changed. Rudder and flap weldments were powder coated interior color.
 
The powder coating on the canopy frame, roll bar and other parts from Van's was not durable and the metal underneath was corroding. I stripped it off to bare metal and applied a 2-pack epoxy primer and polyurethane top coat.

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Powder coating will be generally more expensive because of paying somebody else to do it, unless you have a large enough oven and the equipment to be able to do it yourself.

There are many thousands of RVs that were built and flying before Van's introduced powder coat. Properly applied powder coat is possibly tougher than paint, but properly applied paint is more than good enough for an RV.
 
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Maybe not an issue with a plane that is usually hangared, but, corrosion on powder coated metal almost ALWAYS goes undetected until it gets bad enough to have large areas start to flake off. A lot of livestock equipment manufacturers started using powder coat 10-15 years ago and from what I have seen, it is no better than paint.
 
There is not a huge amount in it for well applied paint or piwder coat. But many powder coaters skip important preparatory steps which leads to corrosion under the coating. Painting simple items like the roll over hoop or rudder pedals is straightforward but painting an engine mount is not. Prep is laborious. However hard you try it is likely there spots that remain unpainted. So sand blast and powder coat by a reputable shop would be my suggestion for an engine mount but paint everything else.
 
I tried to order a Vans engine mount last week bare because I want to prep and paint it myself. I was not able to do so. I used to work almost daily with a powdercoater in another line of work. You can pay money and get whatever prep you choose OR they can cover up whatever you give them and save money. Either way, the job "looks" good.
On an engine mount, I want to know what is under the powder, as the heavy powdercoat could hide a multitude of sins, bad welds and future cracks wouldn't be seen until too late. Who knows how long that mount was sitting around BEFORE it got powdercoated and what kind of prep did it get ? I will order mount, strip and paint myself with 2 part.
 
Powdercoat is fine..."IF" you know how it was prepped....and, IMHO, it's not an engine mount...I want to see a Crack if it happens. My mount will be painted white.
 
FlyHigh said:
Powdercoat is fine..."IF" you know how it was prepped....and, IMHO, it's not an engine mount...I want to see a Crack if it happens. My mount will be painted white.
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When I built my 10, my recollection is the engine mount was powder coated white. Is that anyone else's recollection?
 
For any powered coated kit parts that can be seen after assembly, I light sand with 200 grit paper, thin coat of primer than top coat with urethane single stage paint.

I prefer to match color with the rest of the interior.

Carl
 
dspender said:
When I built my 10, my recollection is the engine mount was powder coated white. Is that anyone else's recollection?
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Yes. Vans furnishes powder coated engine mounts.
Unless the crack was there to start with, powder coating won’t “hide” a crack. If a crack develops, the powder coat will crack also. The problem is with poor prep, the powder coat can start to break away and delaminate. Then it’s hard to tell if it’s just the powder coat or the part. You then need to strip the area and inspect.
 
I had the engine mount powder-coated on my C180. After 700 hours it's discolored from the heat but otherwise hanging in there. For my RV-3B I took advantage of having a company nearby that could do it, and had it cadmium-plated and baked, to eliminate possible hydrogen embrittlement. They were an aerospace vendor and followed the proper process spec.

Dave
 
Trusting a vendor to do a good job of powder coating, amongst other vendors we draw upon for our projects, is difficult for a conscientious builder.
 
Randolph Rand O Plate. Glass bead the part and then prime. Good quality urethane color over the epoxy. Randolph epoxy was developed for the Grumman Ag Cat. There is nothing else that come close. I've been using it for fifty years and its probably been around close to 70 years.
 
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