Powder Coating

[RobS 52]

As we’re headed into the cooler weather season here in Maine, I’m starting to organize my thoughts about beginning the work on the MK IV kit I bought this spring. One of the items that I’m still undecided on is whether it’s worth having the airframe bead-blasted and powder coated before I do anything else.

 

Currently the frame is in various “states†of paint and it looks like some of it was done with a rattle can. Going with the powder coating would sure make everything uniform as I begin the tasks of finishing off the fuselage and then head to the covering phase. I could just paint over everything to get the uniform look, but am wondering if cleaning the metal completely and starting fresh is a better way to go. The kit has been sitting for a long time, but there are no visible signs of corrosion (maybe a few insignificant spots that could be cleaned up and painted). I have a rough estimate of $500 for the complete powder coat job, so, while I'd like to save that money, in my mind it's not a deal breaker as I want to make sure as I start this project I'm doing things right.

 

So I’m looking to see what some of you have done. Is powder coating the way to go or is it a waste of my money? Thanks in advance for your opinions and advice.

[EDMO 1078]

I paid $1000 to have my welded fuselage blasted and 2 coats of epoxy painted on. Some say the powder coating is tougher, and I don't have any info on that. The main thing is to prevent future corrosion.

I only had one option to get it painted quickly the same day after blasting.

EdMO

Edited 4 Sep 2015 by Ed In Missouri

[1avidflyer 1983]

One of the few negatives about powder coating I have heard is that rust can start and work it's way under the powdercoat and while it may look fine on the outside, it then may not be so good underneath.  I stripped and epoxy painted an Avid fuselage last summer, and I think for $500 I would probably let someone else do it.  Jim Chuk

[RobS 52]

Ok - it sounds like the two of you went with epoxy and you'd both recommend the blasting and "new coating" to start. I know Larry recently had his Mangy Fox blasted and powder coated so hopefully he'll weigh in with his thoughts. And, in my reading, I have seen others express concern that powder coating can hide future corrosion.

 

It seems that all the new kits come with a powder coat (I think you can still get them without it). Do you know if they pretreat their frames with something before they do the powder coating to further inhibit corrosion?

[Dusty 126]

If recoating,sandblasting(low pressure garnet is best) would be the only way to go.

I would recommend getting it sprayed with an epoxy tinted to the final colour (industrial epoxy's are self priming and most contain corrosion inhibitors)

A very light coat of 2 pack urethane over this in visible areas will keep it looking good as epoxy will eventually dull off

If powder coating get a zinc base first as it stops the under creep corrosion like you will typically see on cheap outdoor furniture.

Over here powder coating is the cheapest option.

Powdercoating is harder to get right after a repair or modification and if it has to be removed will cost at least twice as much as any other coating to remove

I own an industrial blasting and coating business here(DUSTY!)so have a bit of experience in this area.

Always ask the question, how will this system hold up for the next 10-15 years and after that can it be economically refurbished in damaged areas.

[EDMO 1078]

I can agree with Dusty on the epoxy. I used the same blasting and painting company that did our cranes for the Coast Guard boats. They told me that the epoxy they used would stick to the blasted steel better than a self-etching primer.

I don't care if my white epoxy gets dull in time - it still protects against corrosion. It may get another coating when I spray my fabric.

As far as the blasting goes, I have done a lot of it with a cabinet, and the thought of doing it myself in an open space even with all the protective clothing needed was more pain than I could bear to think of - not to mention all the electric shocks you get when blasting! The thought, and costs, of spraying epoxy at home didn't appeal to me either.

I have heard others talk about hidden corrosion under powder coating, and I can verify that it does happen under a coating of anodizing on propeller parts.

I know little about powder coatings, except that on large flat parts that are exposed to rock or other damage, the early powder coatings I saw would peal off in sheets once delamination started. I guess that tubing that was protected by a covering of fabric might be OK. But, I have powder coated furniture and a saw stand that show rust starting under the powder coating. Maybe the Chinese are doing it wrong?

Some have said that powder coating was hard to remove or repair

I guess some swear by it, and others swear at it!

EdMO

Edited 4 Sep 2015 by Ed In Missouri

[RobS 52]

Thanks for the feedback. Definitely some pros and cons to powder coating. Sounds like epoxy is the way to go.

[C5Engineer 1170]

Just curious why all the factory kits come powder coated?

[Dusty 126]

Powder coating give a good looking finish for a cheaper cost and is generally easier to get right as it is applied electrostatically,

Electrostatic paints are a little more tricky and costly.

Painting kitfox components by conventional spray would be cost prohibitive in a commercial scale.

[Av8r3400 1179]

Just curious why all the factory kits come powder coated?

Chemical painting a tube structure like a fuselage is very, very laborious. Anyone whose ever done it would agree. Like dusty said the electrostatic application process is far less labor intensive (cheaper).

I looked at painting the Mangy, I would have had nearly $300 in paint and primer alone, no labor. I had it blasted, pretreated and powder coated for $168. Easy choice.

[EDMO 1078]

You got a GREAT deal Larry,

If I would have had a choice between a $500 blast, treatment(?) & powder coat, or my $1000 blast & epoxy, I would have taken the Powder coat and saved some money. But I wont own this plane as long as some of you will own yours.

EdMO

Edited 9 Sep 2015 by Ed In Missouri

[Bandit 286]

But is it better?

[EDMO 1078]

But is it better?

Depends on who you ask...Some may think the powder coat is better.

My choice for the limited time and money I have left would be the cheaper powder coat, if I had a choice.

But I think that 2 coats of epoxy is better.

EdMo

Edited 10 Sep 2015 by Ed In Missouri

[MarkD 53]

I have had the blessed opportunity to repair a few tube structured airframes and one was powder-coated. 

 

The powder-coated tubing was a big pain in the butt to repair.  I had to blast the affected area and remove the coating on the tubing after the bad sections were cut out. That was difficult at best. 

 

On the epoxy coated and painted airframes the coatings were much easier to remove far enough back to not be affected by the heat during the weld repairs. Recoating for corrosion prevention after repair was also much simpler.  

 

Refinishing the powder coated tubing turned out to be a compromise by using epoxy coatings in the repaired areas.  We did not want to completely disassemble the entire airframe to have it re-coated with powder-coat material.

 

All that being stated, most builders do not plan for repairs when accomplishing the initial build.   I guess it up to the individual as which one process one considers "Best".  I do stuff with my airplane and go places and have had to recover from minor mishaps (mostly dumb stuff) so I plan for repairs and I want the repair to be as good as the original build.  I used a self priming epoxy on the 4130 steel tubing of my fuselage, outdoor polyurethane on wood structures, and poly tone as the final fabric finish.

 

MarkD