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I think I read that you can apply French polish over polyurethane, just so you dull the poly with a light sanding. Is that safe?

I believe it is. Every finish that I have applied to sanded polyester has looked and adhered just fine.

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John

Yes, but why? Poly is much more durable and unless you go to bare wood before FP there is no sonic benefit to the FP.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Here is why. First ukulele, body all BRW. First try at French polish on anything. Prior to attaching the neck, I had planned to finish the neck in poly, which I started and the body in French polish, which I started. l realized that I will need to sand the end cap after assembly and so need some touch up finishing. As long as neither the poly or French polish are done, I was now considering to just go ahead and assemble before final finishing, which means that the French polish would lap over the neck. Inasmuch as the neck is not near final finish, I thought to just do the final finish on the whole assembled ukulele in French polish. Just what I am considering.

I can't speak to the comparability of the finishes but I will say that if this is your first go round with french polish, you would be better off finishing before you attach the neck. Getting those corners where the heel meets the sides FPed is a frustrating task.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.