Primer question: How to remove?

I have 8 year old primer (2 part) on some skins. And nothing on the primer. They are primed with the intend to paint the aircraft, but that never happened.

Any recommendations on the easiest way to remove it?

Thanks.

Depends.
Do you still intend to paint it? If so, scuff the existing primer and re-prime or top-coat.
If you really want to remove the primer, what kind of primer is it?

It's 2 part epoxy primer.
Ya would like to remove it all first.

Ooof. You are in paint stripper land then, which is a nasty, nasty job. Even the friendlier Napier type peroxide based strippers are a messy job.
I would avoid if at all possible.

Use a methylene chloride based paint stripper listed as safe for aluminum. Test an area first, if it does not completely remove the paint after 5-10 min and dries too much, then for the larger area you can take aluminum foil and cover the wetted paint and that will keep the solvent from evaporating so quickly and allow it to work longer. Use heavy gloves and well ventilated area. Don't breathe the fumes.

You can take clean saw dust to collect the dissolved paint (heap it on and use as a wipe) then wipe the remaining film with denatured alcohol while scrubbing with a soft natural bristle brush (if you can still find one). Use paper towels to get final wet layer off. Finally, wash with clean water with low dissolved solids. Not softened water or hard water and blow out crevices.

Are you really sure you want to remove it?

If you really, really want to remove it, I would suggest you bring the plane (or parts) to an aircraft painter who is equipped to remove the paint and handle the chemicals and waste. Ideally, if you are going to have your aircraft professionally painted, let the painter determine how (and if) it should be removed.

Good luck,

Thats what I was afraid of. You guys confirmed it's going to be a nasty messy job.

It's old primer, I don't really trust putting a nice paint job on top of it. It's been weathered a bit and has kinda a white powdery film to it. You get a thin layer of white on your finger when you wipe it. So I doubt I would want to put a 6k paint job on top of that.

loopfuzz said:

Thats what I was afraid of. You guys confirmed it's going to be a nasty messy job.

It's old primer, I don't really trust putting a nice paint job on top of it. It's been weathered a bit and has kinda a white powdery film to it. You get a thin layer of white on your finger when you wipe it. So I doubt I would want to put a 6k paint job on top of that.

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Growing up I always remember the car guys with the nice engine, wheels, and interior going around town with primer, many never got painted. Primers don't have much UV resistance. Good luck, the painter should have some good comments, it is his job to ensure good adhesion. Maybe you will get lucky and a good wet sand with 320 and an adhesion promoter would get the job done. A professional should really look/see/touch it.

I would happily repaint a plane...if someone else stripped it. Dean has good advice.

Chemical stripper is pretty easy. It sounds worst than it is.

The top coat will wrinkle and scrape right off with the first application. The primer turns more into jelly and pressure washes off nicely. On primer, put the chemical stripper on and after a minute or two start brushing it around with a old brush then power wash it off immediately. It will probably take two times to get the primer off. Do it when it is fairly cool in the morning. If it is starting to dry then you are waiting too long to wash it off. Work in small sections like two foot squares or less otherwise the stripper will dry and you have to redo it.

Now people will think I'm crazy but I didn't use gloves and actually wore shorts stripping my plane. Any time I felt a little tingle from the stripper I just washed it off and had no injuries from the stripper. The gloves were a pain to try to keep good so I ditched them.
I used Kleanstrip from the hardware store. The good stuff with Methylene Chloride. Try to find the newest can on the shelf. I had some that the chemical had evaporated out and wouldn't even strip.

Take necessary precautions protect plastic parts and the environment and protect your eyes.