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I'm loving epoxy filling, the finish is really smooth, as the filling takes care of any small gaps around the binding and the whole thing looks professional. It also levels the finish surface so when the sealer or lacquer goes on, it goes on smooth.

So the question is, is there any harm in epoxy filling the top as well, so that any imperfection, however minor gets filled in, and the whole guitar looks professional without gaps around the rosette, binding, etc..

Will epoxy cause the tone to suffer?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I once asked this and the reply I got was "why? There aren't any pores to fill."

And I agree with that. But I was hoping someone would say it would make the top "tougher". But nobody ever did. And, if you are using Z-Poxy, there will be a color change. Does anyone know of a water white finishing resin?

Michael Doolin wrote that when he used water-bourne finishes, he applied a coat of epoxy to the top, thinned, just to give the top some added protection that he didn't feel water-bourne finish provided on its own. He stated he found no affect on tone. YMMV
I've never found the need with nitro. I drop fill the stubborn areas around the rosette and binding as needed.

I would wonder about problems that could occur when you glued on the bridge. It seems that the epoxy soaks in to a certain extent so it would be hard to get down to bare wood. I guess if you masked for the bridge before pore filling it wouldn't matter too much. just a thought.

It would seem to me that you would eventually have a problem with it cracking. Since tops move more than any other part of the guitar it seems epoxy would not have the flexibility to withstand the continuous movement of humidity changes a top goes through.

I don't know since I never use it but I am sure someone that uses it could tell you better than I.

Cheers,
Bob

I believe West Systems epoxy is pretty water white and won't result in a color change (See Fred Tellier's quilted maple posts/finishing posts and guitar pics)
Same "why?" here. Rosette and Binding areas I understand and do myself, but why add the extra weight in the finishing process when many of us try to make bracing parabolic to keep the total soundboard weight down.
Seems counterproductive, I can't say for sure about tone, but it may have some dampening effect, and the extra weight may well detract from volume/projection.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I use epoxy around the bindings/purflings on the top as well as around the rosette. I do not however cover the entire top. I just work it into the needed areas carefully with my fingers. The reason I don't cover the entire top is because I've always been under the impression that the thinner your finish on the soundboard the better. There are no pores so there is no need for the extra finish on the top IMO

System Three SB112 and Clear Coat are water white. I've used both and liked liked them. They are reported to be a bit more finicky than Zpoxy with respect to mix ratio, but I use a digital scale to measure the components and have never had a problem with cure.

http://www.lmii.com/products/finishing/filler/system-three-epoxy-filler

Regarding epoxy on the top, I have never tried it but may on my next bear claw top. I can't remember who it was but several years ago someone posted photos of a build with a bear claw top that was just stunning. The grain really popped and shimmered. If I remember right he said he used a thin coat of epoxy.

I'm wondering what if first I paint a layer of HHG where the bridge would go so it doesn't have adhesion problem?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I still think a water white finish resin for the top would be a great way to add toughness under a water based finish. May try one of those suggested above. I would not use zpoxy for that. Thanks!

Mike

Seems to me that if the motivation for using epoxy on a guitar top is to fill gaps around the rosette and binding why not address what ever it is in your technique that produces gaps in the binding and around the rosette? It's very possible to have no gaps and lots of folks achieve these results.

If it's the color change that epoxy produces that is attractive why not use egg whites as a "sizing" and get that slightly darker more homogenous color? Or french polished shellac with a bit of color?

This entire thread appears to me as if one is attempting to address the symptoms of something else which, of course, suggests why not address the core problems instead of looking for work-arounds that may, I say may, produce other issues as well.

If epoxy hits the bridge patch before one can glue on the bridge with confidence... every bit of epoxy should be removed from the patch for glues such as HHG, etc. to bond well.

Regarding tone it's too subjective to comment but epoxy does add mass, thick finishes on the top are undesirable as mentioned prior in this thread, but most importantly to me would be to get down the basics of building which includes producing a top and binding that are not fraught with gaps. Again it seems like you are attempting to address the symptoms and not the core issues. This does not seem like a good plan for a desirable outcome.... Just a thought.

@Mike: If you are looking for added strength in a top a thin layer of epoxy is going to do nothing more than painting a piece of wood in that respect. What problem are you attempting to solve that could not be addressed with bracing, top thickness, double tops/laminated tops, etc. Why the need for more strength? I'm not understanding the potential application that you are attempting to address.

Thanks.

Mike Doolin's reasoning, and having used waterborne finishes in the past I have to agree, is that waterborne finishes do not case harden the top in the same way that solvent based finishes do. Waterbornes sit on top of the wood, whereas solvent finishes seep into the surface and harden. So Mike used a wash coat of epoxy on the top. Following his suggestion, I did the same thing. It had no deleterious affect on the sound, and it had the advantage of warming up the color of the top which under a waterborne finish can look a little cold. While you could do this with solvent based finishes, it's unnecessary.

I epoxied a redwood top once and the color change was unacceptable and I had to sand it off. Never tried again. I do epoxy the rosette woods as well.

And... how would anyone know if the tone was changed or not unless the tone was subjectively checked before and after epoxy was applied/ I would suggest any finish changes the tone. Whether one can measure it or not is another question.

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Thank You and Best To All

I'm with you on that, but I did it with spruce. I did not like the look. However, a good clear coat would be ok in my book. I think I will order some of that clear finishing resin.

it's not for me i'm afraid. i suspect too much dampening and i don't even want to try. there is so little on a top that needs fill i don't see the point.

would Hauser have done it?

I have done so on many of the guitars I finished myself. As for affect on tone, couldn't say that I noticed a deleterious result. But how can you really say? How much is really left behind in a good thin application? Why would it be worse than the equivalent thickness of shellac? Poly? Nitro? Whatever...

I always did it because the epoxy was amber, and getting a clean line at the transition from smearing the rosette and binding edges never really happened, so I did the whole top.

Hesh,

Even if you have a perfectly inlayed rosette, if there's any wood involved such as burl and the radial designs currently en vogue, some pore filling will be required.

Also some rosettes just have void in them naturally, or are at least somehow uneven. They are so thin that any attempt to sand them out would mean going straight through them, so I think they do need filling. Also no matter how hard I tried, there are always just enough variance with router bits that I can't ever get a completely gap free rosette glue ins.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I agree with those who say it's not necessary. There are no pores in the top so pore filling is not necessary. For minor gaps in binding and rosette I usually use stick shellac, sometimes use CA, and other times just sawdust and glue (not on a light spruce top but along the sides). The one trick I learned a long time ago in regards to rosettes is to score the inside and outside lines with a razor and circle cutter. Even when using the best brand new router bit you can get you might just tear something out but the scored lines stop the tear out.

certainly true. the pre-scoring of the cut makes all the difference. if you score to depth or a few thou deeper, you don't even have to run the bit all the way to the walls of the channel. the pieces just fall away on their own. it also helps to score and cut the channels in quadrants to avoid snagging some fibers and tearing them out.

If I was to do it I would do it pretty much like RusRob does. I would mask off the fingerboard extension area first, don't want anything there.

In reality I don't usually do it. I just use CA on the binding and rosette installation and that pretty much fills them.

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Joe Beaver
Maker of Sawdust