Stripping paint

[Kahle76]

I need to strip the paint from my flapperons, straighten out the trailing edge, fill the dents and repaint. I purchased some aircraft stripper by Kleanstrip and started to remove the paint yesterday. Brushed it on, waited 15 minutes, scrapped with spatula, repeated, and rinsed with water. The paint came off, but the green primer is very stubborn and I'm having a difficult time getting it off.

Questions:
Any tips to remove the paint and primer other than what I'm currently doing?
How do I straighten the trailing edge to make it as unnoticeable as possible?

Thanks for your help,
Mike Kahle
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[PapuaPilot]

Are you using the Kleen Strip for aircraft that comes in the blue can? That is what I always use and I buy it at O'Reilly Auto Parts.

The main trick for the hard to remove paint is to put it on thick and let it do its thing. If you put it on thin you may have to do 4-5 coats before it gets it all and you end up using more stripper.

BTW this product works great for stripping powder coating too.

[Dave S]

Hi Mike,

Stripping paint can be a project that that can challenge one's patience.......Because of the thin aluminum structure of the flaperon, some of the more agressive ways of removing paint (body grinder, abrasive blasting) are out of the question...chemical stripping is a good way to go.

A couple things to think about. even if you just get the top coat off and the green coat stays (primer) that is not necessarily a bad thing if the original primer is firmly attached....a person can wet sand the remaining primer (medium fine wet/dry sandpaper with a lot of dish soap water) and do a thin coat of primer over the prepped original primer...biggest challenge is feathering with the sandpaper where some flakes may have come off. On the pther hand, if the primer is not all that well attached, probably better to remove it too if you can. Any bare aluminum should be treated with metal prep (phosphoric acid etching stuff which is sold under various brands for aircraft and auto bofy metal etching) Lots of scrubbing and rinse water to follow the etching.

A couple cautions......the stripper is likely a methylene chloride concoction which can cause trouble other stuff you want to keep such as the foam ribs inside the flaperons and possible the outboard end cap which is normally made of foam or plastic. I'd be real sure not to let the concentrated stripper get inside the flaperon or the endcap and your water flush is extremely important. a scrubby made of shag carpet and a pail of dish soap water is useful getting residue off of where you can reach.

Another thing a person can try is scrubbing the paint with MEK (Methyl ethyl ketone) - again - don't let it get inside the flaperon or on the plastic end cap. Don't use anything other than a cotton rag for the MEK. MEK won't bother epoxy adhesive or paint; or, catalyzed urethane paint but it wil take pretty much anything else.

The biggest source of later issues with chemical stripping is residue that was not cleaned off or stuck between layers of metal before new paint was applied so it's essential to be sure a good job of washing/scrubbing is done after stripping.

Don't know what to say about the trailing edge dents except that light hammer/dolly work may help - if the metal has been streached much, it's pretty hard to shrink it back completely to get a perfectly straight edge.

It's a challenge----patience trumps this one

Phil's comments about using a heavier application is right on.

Sincerely,

Dave S
KF 7 Trigear
912ULS Warp Drive

[Kahle76]

Phil,
I did use the same product and I thought I was putting it on thick using a 4" brush. I will be more astute next time. The Polytone? paint came off, but the primer was more stubborn and some patches came off, but most stayed. I watched a video on YouTube where they sprayed the stripper on and the pain literally fell off. Probably need to lower my expectations.

Dave,
I did try MEK as a test and it did not take off the primer. Thinking that stripper would take the paint and the primer off together was the reason I went with stripper. Thanks for the advice on keeping the stripper away from the foam ribs. I noticed that it was softening the foam end cap.

Thanks gentlemen for the advice.

[SkyPirate]

can you show a close up picture of the trailing edge? I don't want to tell ypou to drill the rivets unless its necessary , you might be able to repair it with a body hammer and Die if it isn't too bad

[rv9ralph]

Another suggestion to improve the action of the paint stripper is to brush it on then cover with plastic kitchen wrap (Saran Wrap or equivalent). It will hold the stripper in place and keep it from drying out while it works. If the stripper dries in place, it will need to be treated the same as the paint coating to remove.

Heed the cautions about getting the stripper on any non metal surfaces. And in removing all traces. After Rinsing/cleansing, blow off all moisture with an air nozzle.

And remember, always wear protection!

Ralph

[avidflyer]

Quite likely the "primer" is actually epoxy. One of Poly fibre's suggestions for painting aluminum or fiberglass is to shoot a coat of epoxy, and then as it's setting up, shoot another coat of poly tone into it. Not sure how good the stripper is at removeing epoxy. (maybe you need to get her some sandpaper LOL) Jim Chuk

[dcsfoto]

a trick I learned from a pro that helped me was, brush on in one direction only. when you back brush is puts air in the stripper .

D Kelm SS7

[Kahle76]

image.jpg

Photo of the Flapperon trailing edge showing the damage cause by moving.

[SkyPirate]

Ok that damage can be repaired with a flat die and a flat head body hammer,..get it as flat as you can with a pair of pliers then use the die and hammer,.try not to use too much force as squishing the material will expand it