Minwax over epoxy grain fill.

I have mostly used Tru-oil finishes on my ukes to date, but I used Minwax wipe-on satin poly for the first time on the recent 2x4 challenge Scots pine concert. I liked the results enough to want to try it on more instruments.
There was no need to grain fill the pine, but the new one is an open pored mahogany that I would normally epoxy fill and coat with shellac before applying Tru-oil. I am wondering if it is still advisable to apply a barrier coat of shellac when using Minwax? I have done a site search but couldn't find any specific advice, and the instructions on the tin don't really cover this situation.

Maybe you could try it on a scrap piece first?

MinWax satin is much thinner than Tru-Oil. If you don't like the way it looks over the epoxy filler it shouldn't be a big deal to get it off again. MinWax gloss wipe-on is more like Tru-Oil, only easier to work with. It sands to a nice dust between coats and doesn't clog the sandpaper. I've used the satin version as a wipe on/wipe off, sanding in the first coat while wet as a pore filler, and wasn't pleased. On my 2x4 uke I used the satin as a wipe on, trying to build a coating. It's much glossier than I expected it to be. BTW, I put my first can of satin into a plastic bottle to make it easier to use. It didn't take very long for the whole bottle to turn into a hard jell. Leave it in a light-proof container.

jcalkin said:

I've used the satin version as a wipe on/wipe off, sanding in the first coat while wet as a pore filler, and wasn't pleased.

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Thanks John. That was an option I was considering, so I'll stick to plan A for now. On balance I have decided to use a shellac coat on the basis that it sticks to everything and is unlikely to do any harm. It doesn't really take much extra time to do. Ref. testing on scrap, I have done that before with other finish combinations, and whilst it obviously reveals any major short term chemical incompatibilities, as I found out it doesn't reveal much about the longer term durability .

Have you tried paste wood filler? It's typically used to fill pores on mahogany, as with pianos, and other furniture. And then lacquer or other finish on top. I'd be curious if the poly coating doesn't "deaden" the sound, as my impression is it's a thick coating.

I'm in the UK, so don't have easy access to some of the products available in the States, however I used Rustins "natural" coloured grain filler (which I stained to match rosewood) followed by nitro lacquer on my first few guitars. It worked OK but even with a laquer washcoat, the stain transferred into the wood and I wasn't that happy with the result. I have also tried a coloured version of the same filler on mahogany.

Having been introduced to the concept of epoxy grain filling (BSI or Zpoxy finishing resin) by Pete Howlett, I find it works well for me - I follow the guidance on Allen's Barron River Guitars videos.

I can't comment on poly finishes in general, but Minwax wipe-on satin is very thin. I used 3 coats on the 2x4 concert, and was concerned in case that wouldn't prove to be enough. After 2 months use, I'm happy with it.