You are currently viewing Kit Guitar Forum archives. To view the current forums go to


Beginner's question about Poly finish

Total Topics: 3
Total Posts: 9
I bought an Epiphone AJ00Re and I've been working on bettering it for the last month or so. Sanding down the poly finish, trying to make it thinner, more free sounding and have some sense of wood coming from its surfaces.

I found this forum while I was looking for some answers to various questions that've come up along the way and though I'm a touch reticent to ask fearing some heated response like 'You're destroying that guitar!', I've found plenty of excellent tips here on how to avoid doing just that (Destroying my guitar that is).

My first real question: If you were to attempt what I'm doing, what advice would you give? What should I avoid doing at all costs and should I reseal the wood after I'm done?

I've been sanding the guitar in steps with varying grades of paper of 320 through 3000, mostly dry sanding but once with some olive oil during the finish step. I then do a final finish with a damp rag and polishing compound.

I had been trying to retain the mirror finish until this week when I became frustrated with how much finish was still on the guitar and I made a big effort to get to some woodgrain. Now I'm finding that, the back at least, wont lose a hazy effect and there are some directional scratches that wont sand out, it seems. Leads me to think I should reseal the wood and polish through the steps again.

Should I take all the finish off the back, reseal and polish the sealer? Is a back without finish stable and tonally ok?

Your wisdom and experience in these matters will be much appreciated.

May 28, 10 | 6:48 pm
blues creek guitars Authorized Martin Repair Ctr

Total Topics: 52
Total Posts: 1011
You can't really sand out scratched you need to polish and buff them out. Start wet sanding with 800 and work up to 2000 grit. You can get the wet papers at most auto stores.
Buffing and polish compound are also available there. Finishing is an art and it is the details that make or break a finish, Take your time

John Hall
Blues Creek Guitars Inc.
Authorized CF Martin Repair Center

May 29, 10 | 2:48 pm

Total Topics: 3
Total Posts: 9
Thanks John,

For your suggestions. Do I wet sand with dampness/water or with something else?

May 29, 10 | 5:15 pm

Total Topics: 1
Total Posts: 4
I like poly but have to admit that its harder to get a thin finish with it and it is harder to polish then lacquer. You have to beware it can be easy to sand through the finish coat to the undercoat. So be careful since the undercaot won't polish like the finish coat. For sanding you can use soapy water. Dish detergent works well.

May 29, 10 | 9:38 pm

Total Topics: 3
Total Posts: 9
Thanks for your advice Mike. I might start into this again tonight.

May 30, 10 | 4:19 pm

Total Topics: 27
Total Posts: 668
Danny, first, welcome to this forum. Second, I tried googling your guitar to find out how it was built so I could add some suggestions, but that number does not seem to be a valid Epiphone model.

But I'm also going to be the one to rain on your parade. Poly finishes are put on guitars for very good reason - they are hard due to the catalyst, give a very nice deep looking finish, and stand up well to playing and abuse. It goes on shiny and doesn't require the sanding and polishing of other finishes. Some very high end manufacturers use poly finishes including Taylor, Mike Doolin, as well as many asian companies. Sometimes they are a little thick, and as you know, some people feel that thick finishes do dampen the sound of a guitar.

The best way to get a thin finish is to start that way applying very thin coats of finish and building up just enough - then giving it the final polish that John describes. Trying to thin a thick finish by sanding frankly isn't going to work very well - you run the risk of sanding thru in some places ahd scratching it in others.

If you use agressive sandpaper to try to thin it you just get scratches (which you know) and they will be very hard to polish out (remember why we used poly in the first place). About all you can do is stop screwing around with it - go thru the steps of wet sanding starting with 600 and going all the way to 2000, then polish on a buffer. With luck you'll recover some of the damage that you've done, but don't count on it.

If you've done a lot of damage to the finish poly is really hard to fix - probably your best choice is going to be taking it to bare wood and starting over - which is a huge can of worms. Frank Ford at shows refinishing a Taylor with a little nitro, but he says it doesn't work very well.

I'm also going to really p*ss you off and say that I seriously doubt that you will "better" that guitar by sanding a few thousands off the finish. It is possible to change a guitar that has already been built (the most common is doing a little scalloping thru the sound hole, but that is not a task for a beginner). Epi's are nice sounding budget guitars - why not enjoy it for what it is and consider building a kit to do your experimenting?

Jun 01, 10 | 7:05 am

Total Topics: 27
Total Posts: 668
Interesting coincidence at UMGF

Jun 01, 10 | 10:52 am

Total Topics: 3
Total Posts: 9
Hi Freeman,

Thanks for the welcome, your ideas and for the caveats as well. The model # is AJ500re Masterbilt.

>>I'm also going to really p*ss you off and say that I seriously doubt that you will "better" that guitar by sanding a few thousands off the finish.<<

Not bothered at all and thanks for your knowledge!

It comes with a flat satin finish that is definitely thicker than it needs to be. Interestingly though, I have already noticed large differences in the sound quality and the projection of the guitar.

OEM it had a voicing that doubled on b and now it doubles on g. It's absolutely louder and has gone from having a scooped midrange to a tighter individual string voice that is more suited to fingerstyle. Two things I'm less happy about are an apparant loss of bass projection and less harmonic complexity (Both probably the result of the guitar projecting with more volume).

My aim in playing with the finish of the guitar was to make the guitar more suited to me, have it also look/feel more like an older guitar and to learn some things that I'd like to know. I may have gone a bit too far on the back (I didn't get to working on it again quite yet) but that won't matter to me much when all's said and done as the guitar has become more personal to me already and I'm loving it.

I do think of this as a presage to my building my own guitar. That's definitely something I need to do within the next year or so.

Jun 01, 10 | 1:50 pm

You must be a registered and logged in member to post in this forum