Hi all, I've been enjoying reading all the restoration threads on here that guys have been posting. I am taking advantage of the long Idaho winter and repainting my 172. In my research on painting airplanes, it looks to be standard practice to strip to bare metal, and then Aldine, prime, and paint. My question: is it necessary to actually remove the original zinc chromate green primer when repainting? I have been using a paint stripper that works very well to remove the paint, but it doesn't seem to touch the zinc chromate primer. Would it be a mistake to simply prep the existing primer, and shoot it with another coat of primer, and then shoot the top coat? If that original zinc chromate is this hard to remove, then maybe it is pretty good stuff and should be reused Thanks guys!

In general I would try a different stripper, the old primer will come off, you just need the right stripper for it. Sometimes some scotch-bright to break the surface can make a big difference on the stripper digging in to it. You are putting lots of time and money into this, do whatever it takes to start with an immaculate surface including rivet heads and seams with no residue of any kind that can come through the new primer and paint.

I have used these guys for paint supply and technical advise.

Automotive Industrial Supply
MONTANA, IDAHO, NEVADA, UTAH
Ogden, UT 84401
Phone:(801)732-1500 mail: [email protected]

You probably know all the other usual cautions, take no chances with personal exposure, use good equipment, have or make a paint booth and don't take temperature or humidity chances with painting.

I was going to suggest a scotchbrighting and then more stripper. I wouldn't want to take the chance that residual stripper was left in the primer coating.. it could wreck 5,000 worth of materials. Plus your time. Depending on the vintage of your existing paint, you might have to use scotchbright and gun wash, to remove all the primer.




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Thanks guys for making good sense. You're probably right. It would be terrible to see shiny brand new paint peel off after its applied. Have you ever used a stripper called Webbertek Sunset Strip? I've been using both the Klean Strip "aircraft" stuff and this Home Depot stuff called citri strip. So far the citri strip has worked way better than the nasty Klean Strip stuff. One problem I have with the nasty stuff is I can't keep the shop warm enough and still have the ventilation needed for survival. Any good paint removers that you have used? Thanks again.

We use molecular tech efs 2500. Environmentally friendly but not personnel friendly. And we use proform aircraft paint stripper if the environmental stuff doesn't work.

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What we also do is try to spray the stripper on, on Friday at the end of the day and come in on Monday to remove it.. keeping the shop heated and no one around. And all the rest of the applications we always try to do at the end of the day and let the paint stripper work while we aren't there.

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I would verify Zinc Chromate vs POSSIBLE 2-part epoxy primer in near same green.