Looking for DIY finish advice.. french polish?

[downtime]

First the background:

I purchased a small shop luthier built guitar that had been signed and auctioned off after a music festival. The auction winner had played the guitar and it now has pick scratches and quite a few small nicks and dings in the top. It also has the appearance of being "splotchy" with areas that are flat and others shiny. Some areas are extremely thin in the finish and bare wood can be seen.

The guitar has a redwood top, zebrawood b/s and cocobolo binding and has a really nice tone and playability.

I decided to try and remove the signatures and called the builder for advice. He informed me that the guitar was commissioned for the music festival and due to time constraints, a true finish was never applied. The guitar had z-poxy applied and nothing else. I used naptha to remove the ink without problems but the lack of a finish is now even more obvious.

Now the questions:

What type of finish could a novice successfully apply? Shellac in a french polish seems doable and I found a lot of info and tutorials.

Can the Shellac be applied safely over the z-poxy? Will the pick scratches and dings cause problems if they are not filled? Some are quite deep. I'm not really concerned about fixing the dings, just not sure how the shellac will look applied with the scratches not filled.

Any other options or suggestions? Thanks in advance

Hopefully pictures will help

[marioed]

Shellac will go over z-poxy very well and french polishing is one way you could go. Another option might be to use a water based lacquer like Target Coatings EM6000 which can be brushed on if you add retarder. If possible I'd suggest taking the guitar back to wood so you don't have to worry about any possible contaminents that may have been introduced, fixing the dings and scratches, and then pore fill with z-poxy. Depending on what type of wood the soundboard is you may not need to pore fill it before doing your top coats. Closed grain woods like spruce don't have to be pore filled before finishing. After pore filling apply a couple of wash coats of shellac before you start french polishing. The cocobola bindings can be tricky, it is a very oily wood and they may want to bleed color.

A couple of other things. While shellac will go over z-poxy very well, z-poxy does not go over shellac. You want bare wood for z-poxy. Not fixing the dings and scratches can cause problems in getting an uneven build up of finish and they may become more pronounced after finishing. If you do decide to french polish make your own shellac from unwaxed flakes and alcohol don't use premixed shellac. The technique of french polishing requires some skill, you may want to prepare some wood samples to practice on before trying it on your guitar. If you leave the bridge and neck on, working around them can be tricky so be careful. Keep in mind that shellac is not the most durable finish, it scratches easily and doesn't react well to water. On the plus side it is easily repairable.

Regards,
Ed

[Rod True]

I would sand back to wood, especially on the top. Most likely the back and sides will still have enough z-poxy to fill the pores. You don't need to worry about pores in the redwood.

The nice thing with shellac is that its sort of hard to go wrong. It's very easy to fix if you make any mistakes. Just take your time. As you said, there is lots of good information out there for shellac applied by french polish.

The other thing you can try is Birchwood Casey's Tru-Oil. You can rub it on in very thin coats and build up a thin, level finish which looks good when buffed out. LMI has a good article on applying Tru-Oil finish

Nice guitar, who made it?

[downtime]

Originally Posted by R. True

Nice guitar, who made it?

The guitar was made by Jesse Stearn, a local builder here in Salt Lake.

Thanks for the suggestions, I'll take a look at the Tru-Oil article.

[dekutree64]

Originally Posted by marioed

Keep in mind that shellac is not the most durable finish, it scratches easily and doesn't react well to water. On the plus side it is easily repairable.

The water thing isn't entirely true, actually. Brushed on shellac will turn all white and ugly if it gets wet, but a proper French polish creates a smooth, solid shellac layer that's quite resistant to water. I've only done one, and it took a while to get the hang of it, but it turned out great. Plus it's environmentally and health-friendly (as long as you use drinkable alcohol rather than denatured.. and don't drink too much of it )

But one of the big advantages of FP for me is not having to use epoxy or anything to pore fill. So since you have that done already, it might be easier to just brush lacquer or tru-oil over it and call it done. FP might not be worth the trouble to learn for a one-off.

[Bob V]

I don't see any reason to cut back to bare wood. The hard part has already been done with the pores filled and the finish leveled with zpoxy.

The most forgiving newb finish is nitrocellulose lacquer in a spray can. Deft is one popular brand, but there are plenty out there. Spraying, even with a spray-bomb can, will get a much better finish than anything you could do with a rag or brush. Sure, french polishing gives a fantastic finish, but the learning curve is rather steep and quite frankly you don't want to do the first job on a nice guitar like that.

Then once you get hooked on finishing guitars, then we'll get you interested in EM6000 and the other wonders of water based coatings.

[downtime]

Thanks to those who posted suggestions and advice.
I decided to apply a Tru-oil finish and I'm happy with the results. The hardest part is being patient between applications and the final coat to allow curing.

Here are some pics of the results:

[TomDl]

Is it normal to Zpoxy a soundboard? I thought that stuff was just used to fill pores, often prior to French polish. Has anyone had problems yet with epoxy? I have had decades of experience with the stuff, and it yellows badly over time, but then, guitars are different, and Zpoxy is yet another brand of epoxy I haven't actually sampled.

[dekutree64]

Zpoxy normal for a soundboard... I think not. But softwoods do still have a texture to them that takes a while to fill in with shellac when French polishing, so pumice filling is not a bad idea. Most other finishes build up thickness much more easily so a filler isn't necessary.

As for yellowing... I've never heard of any problems with it. I think the idea with Zpoxy is to sand back to bare wood, leaving the epoxy only in the pores, where the color might not be so noticeable. Never used it myself though, and I don't know if it's even been around long enough to have old examples of how yellow it gets. Although I'd guess other epoxies have been used as filler for a long time, so there are probably some yellow-pored guitars out there to see if it looks bad.

[TomDl]

I'm pretty sure other people leave it on thick enough so that it is over everything, not just pores, and certainly not on soundboards. That is what I have done. In a video I saw, the guy using the zpoxy said he chose it because it was more amber than WEST, which can be pretty amber. West goes virtually black over time. I have some going back 30 years on indoor stored boats. But a lot of te4 50/50 mixes go seriously yellow in a year. Of course, it is a really thin layer, so it isn't going to tint the guitar all that much, but it is a sign of the epoxy starting to break down. I wouldn't want to create another shrinking plastic binding like problem for the long term. I gotta say I use it, but then I don't sell stuff, so nobody cares.

[Kitchen Guitars]

You squeegee it on or use a credit card. Thin. More means more drying time and sanding
Wait
Sand off.
Do it again.
Sand it off.
Not on topwood.
Been told Shellac sticks to Zpoxy, Zpoxy will not stick to shellac

[Battleman]

Bowling Alley Polyurethane is what im trying, ill let you guys know if it kills the tone or what happens, when fully cured. Sure, looks good, but that doesnt make a great sounding guitar. Im only putting it on the back and side and using some of your comments on the top..Cheers