Prime & paint? Or Powdercoat?

[freightpilot27]

Any recommendations on what primer and paint to use on the fuselage and tail structures?
Any thing wrong with powder coating them?

Thoughts, Comments, concerns?

Thanks,

[AndyDuke]

Re: Prime & paint? Or Powdercoat?

Bob,

I'll be using an etch prime and epoxy primer on my tubes, plus a top coat where the tubes are visible around the cockpit. Powder coating can be a bugger to remove at a later date and is very effective at hiding any corrosion until it's too late.

Andy.

[PT13Pilot]

Re: Prime & paint? Or Powdercoat?

We experimented with powder coat a few years ago and weren't too happy with the results. At the time I was building and maintaining Bell 47 helicopters we were spraying with. At the time we found a place that would blast the center frames and tail booms, which are the same tube construction. And getting tired of blowing 4 gallons of paint around the shop to put a quart of paint on a frame, we decided to try powder coating. It looked great and wasn't very expensive. And the guy that blasted the frames also did powder coating and had an oven large enough to do the tail booms too. The powder coating seemed tough at the time. Later on we discovered that anywhere you chip it, or grind it off for assembly of parts, or ground straps etc, it let water, chemicals and anything else to get between the coating and the tubing and spread around. And since powder coating goes over virgin, blasted tubes, the corrosion was fast and furious in those places. And you don't see it untill you chip of the powdercoating (it will still look great when the tube is almost gone!). A good epoxy primer will adhere and bond with the tubes. If you chip it to bare metal, it might rust at that spot, but won't tend to grow from there. Powder coat is a coating, you're basically encapsulating the tubes in plastic (for lack of a better description). Damage the surface and water and other things can get between the coating and the tubes. The helicopters I mentioned obviously had much higher levels of corrosion due to the chemical we sprayed on a government contract, but I looked at it like a torture test, and was not happy with the results. And on the 47's you can look at all the tubing and keep an eye on it. If you did it to a fuselage frame on a T-Craft or similar, covered it with fabric, and bury it in all those places you can't see very well, corrosion can be going crazy and you won't know untill it's too late. And the tubes will outwardly still look great, because the powder coat will still be nice and shiny.

That being said, I still powder coat a few things that aren't structural and that are high wear areas. It works great on aluminum yokes and things like that. Stick with a good epoxy primer and 2 part top coat in areas you can see and forget about it.

[Robert Lees]

Re: Prime & paint? Or Powdercoat?

Amen to all that.

Powdercoating and aircraft do not make good bedfellows.

[GLB]

Re: Prime & paint? Or Powdercoat?

Agree with PT13 Pilot, Kitfox guys have found the same thing with fuselages that have been powder coated, not good.
As Robert said aircraft and powder coat are not good bedfellows.

[TimHicks]

Re: Prime & paint? Or Powdercoat?

My new struts are on the way here. The salesman at Univair said that the struts come in a "red oxide primer".

Should I plan to strip that off and apply zinc chromate epoxy primer. Then acrylic enamel topcoat? Or something else?

[taylorcraftbc65]

Re: Prime & paint? Or Powdercoat?

Tim,
I have been trying to GET zinc chromate primer to prime the BL-65 that we are restoring to look like the Israeli one that dropped the explosives on the palestinian gurrellas in the 1947 war.
EVERY paint store that I have asked at says it is now a banned substance, and can NOT be gotten, or even USED. That's too bad, as I don't think there is ANYTHING that works as well. Brie

[Buell Powell]

Re: Prime & paint? Or Powdercoat?

Have you tried Univair or Wag aero?

[TimHicks]

Re: Prime & paint? Or Powdercoat?

Ok I didn't know about that. So not Zinc Chromate. But I'm curious whether I should strip off the Univair primer and shoot epoxy primer on the bare metal. Then top coat.
Someone offline suggested Polyurethane Top coat from PPG.
Anybody know anything about that?

[astjp2]

Re: Prime & paint? Or Powdercoat?

If you replace the red oxide primer with zinc chromate, you are WRONG! The Oxide primer is self etching for steel and chromate is self etching for aluminum.

For those of you that think that powdercoating is not good for under fabric, check out the Airframes inc site, the Atlee Dodge site and Dakota cub site, they all powder coat the tail feather, landing gear and most replacement fuselages can have it done also. I will not recommend it for applications that sit out in the sun like cowlings and doors, they fade, but its great under fabric. Just my thoughts. Tim

[TimHicks]

Re: Prime & paint? Or Powdercoat?

I think I'll start a new thread regarding painting struts. Sorry for hijacking this thread.

[freightpilot27]

Re: Prime & paint? Or Powdercoat?

I think i know what im gonna do now.
No powdercoating for me.

BIG Thanks,

[flybikefarm]

Re: Prime & paint? Or Powdercoat?

Did you get the pics Bob. George

[Ragwing nut]

Re: Prime & paint? Or Powdercoat?

I will not powdercoat fuselages or engine mounts. If you have to repair one in the future, you have to grind the powdercoat back, make the repair, and paint the repaired area, no way to re powdercoat. We have in the past powdercoated tail feathers and other small parts that can be replaced if damaged. I have gotten away from it because the finish will hide any rust underneath until it is too late.

You have not been able to get "real" zinc chromate for years. Plus I won't use it because chromate will absorb moisture from the air and rust right through through the paint. Stits has a dark epoxy that is very close to green chromate. I always request it when buying from the Millers.

Mike

[Forrest Barber]

Re: Prime & paint? Or Powdercoat?

Good thoughts in this thread. I too do not use Powder Coat on mounts, fuselages, etc. their are some uses as mentioned. We are doing a fuselage here and will try newer methods soon...