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I have been using West Systems pore filler (I think it is 207?) and I struggled at first. As Todd said, I find it does penetrate into the wood and I always feel I am sanding more off then I put on (i.e sanding some layer of wood away also). Sanding back to wood in this fashion always exposed new open pores for me. Lately I have been putting a coat of waterlox down first as a sealer. The West will cure over the waterlox and rubbing the waterlox on ensures it to be ultra thin. If I sand through when sanding the epoxy level I can just touch up with a dab of waterlox, which will also cure over the epoxy. I find this much easier than using a diluted epoxy wash. Later if I find any small pores that were missed I will drop fill with CA.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Burton

Is that the Waterlox sealer you use and what are you using for finishing over it after the epoxy? I was actually thinking on my next Z-poxy job to start with the 50-50 epoxy to soak in a little and seal the wood, then use the normal coats and sanding. On my 1st 2 with Z-poxy sanded to bare wood I have a little shrinking into the pores after 1 year so I used the wash coat on the next 2 as I think I may have exposed some pores that I didn't notice sanding back to the wood.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Fred,

I am using the normal finish (it may also be the sealer?, I am not as familiar with the product line as maybe I should be), the one with red label. The high gloss one (green label) is harder to get a consistent surface. After the epoxy is on and sanded back I put another thin coat of waterlox over it and then scuff sand lightly. Lately over that I spray a shellac coat and then the Emtech 6000 which is easy to use but I have been having trouble getting the surface as smooth as I would like after buffing. I posted on the forum on the target website but have gotten very little useable feedback. I would also not hesitate to french polish over that base ground, the shellac sticks very well to the waterlox and the epoxy.

In theory, using an oil as a first coat should be a bad idea if we assume that anything penetrating the wood (especially an oil) promotes damping but in practice I cannot notice any negative sound affects at all. I do not do it to the top however. The first thing to touch the top is shellac. If I have anything to fill on the top (purfling mini gaps, pores etc..) I use either a lacquer stick or CA over the shellac if it is close to the spruce. Depending on the rosette sometimes I will mask off and Epoxy fill. I have found that the West Systems epoxy penetrates even deeper into the spruce than other woods, which is not a surprise.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

I'm not saying it's moot as a pore filler (maybe moot to me at this time because of personal health concerns then application bumps. That hasn't stopped me yet. ) but I'm trying to understand all the benifits to it over other fills. But so far it seems like the one benifit to it over other pore fillers is it pops the grain and it's somewhat clear or amber. I understand the use for it with the waterborn that David mentioned. And I understand the process will get easier just like the second time I used a paste filler. I'm just saying with all the health issues and wearing a Respirator not a dust mask and the washing of clothes etc. that's been mentioned it just doesn't seem worth it to "me" for just poping the grain.
That's why I ordered a sample kit of the Ecopoxy to give it a try. If I can use an epoxy that I don't have to worry about the health issues( especially the dust and fumes and if it's self leveling which would be a plus) and does a fine job then I'd have another option and perhaps a healthy one and have something that pops.
He's another question that came to mind on my way to Woodcraft to get some super blonde shellac flakes. It has to do with what Hesh said about not wanting to have epoxy as a finish. If people are putting on a layer of a epoxy "Finishing Resin" then why can't that be the finish? Does it not get hard enough or buff? The Ecopoxy is used as a coating as that's what it's designed for.
And is there any reason that one couldn't pore fill the back just after the back plates are thickness sanded?

I'm also not bashing epoxy and thought this was a pretty good discussion. Pretty much showing different points of view and bringing facts and questions and answers to the table. If I've given that impression then I apologize as that's not my intent.

Right behind you, Todd!

The school where I learn some 20 years ago just started to use epoxy soon before I left the school. So that's why I decided to try it when I started building back again. Tried other stuff but as others pointed out, nothing pops the grain like epoxy. They where also scraping it off rather than sanding it. So without questioning myself too much, that's what i did. When I heard about people sanding epoxy during the pore filling process, I gave it a try. It turned out to be waaaayyyyy harder, messier, gunkier, slower, wateverer than scraping it off. One trick I believe I read here, once the epoxy is fully spread, but still soft, I pass a rag (or heavy duty paper towel) over it to even everything out and get rid of whatever runouts that might still be there. Makes your life a lot easier when scraping it off.

Hope this helps!

P.S.: Still where protective mask when scraping though...

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Never get CA on your teeth. It will kill them.

I thin 5 minute epoxy with a bit of alcohol and squeege it on. After about 2 hours MAX.,I sand it off. At that time period,it is "leather hard",and rolls up in little footballs and falls off. I have no problem with fumes or dust. I repeat this operation. It fills the wood fine. Then I can get a very nice finish with just a few coats of nitro.

If you wait too long to sand epoxy,it is like sanding concrete,and I'm too old for that,or breathing the dust. Maybe you guys are waiting too long to sand your epoxy.

I don't go for the "grain popping" but I don't use waterbased finishes. Also, I only fill the pores, I don't leave a layer of epoxy on top of the wood. I'm also not comfortable using paste fillers under catalyzed finishes. (They're probably fine, just not in my mind)

Anyway...........the benefits? Epoxy doesn't shrink. Most fillers (excluding CA) shrink. Some tend to shrink for a long time. Some people like the look. I try to match my filler (and finish) to my clients expectations.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Any thought to why not pore fill the back after thicknessing the plate. I'm thinking it would be much easier to sand level or at least quiter then on the box and if using epoxy with a wash coat or even shellac and pumice it would seem that it might offer up some protection to the back during assembly.

I usually end up sanding everything fairly aggressively once it is put together, I'm not sure filling beforehand would do much good. I do flood with CA for some woods on both sides not too much before final thickness and I don't notice the grain filling to go any easier when I do that. I used to do a pre-fill before i routed the binding slots and that helped a little but it really wasn't worth it in the long run, I still ended up doing 2 coats later.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Any thoughts about the fill after thickness sanding Todd? Or using a resin finishing epoxy as a final finish? Why or why not, it seems you have had quite a bit of experiance with epoxy coatings.

The benefit, as I see it, to epoxies is the total lack of shrinkage as it cures. The problems with epoxy is getting it down in the pores and penetrating the wood to some extent with a rubbery substance. If sanded to unsaturated wood, (Walnut in my case), I have to sand down to a level that is sometimes deeper than the penetration into the pores. Looking under magnification just behind the squeegee I see that the epoxy has been forced down into the pore and compresses the air under it like a little air spring only to boing up right after the squeegee passes. Producing a little pouched bubble. These are what look like dust on the surface after squeegee(ing?). Thinning it w/ alcohol produces a softer final cure as I understand it. If thinned epoxies were to be used, I would think it would be better to use it on the first coats rather than the later. This would aid in penetration of the pores and the wood for those utilizing it’s grain popping effects.
For those of us who would like to just have it in the pores, what about the Shellac wash coat under the Epoxy? no penetration into the wood accept in the pore so after sanding back your left with a small shellac shell, holding an epoxy yolk in the pore. I have herd about adhesion problems with epoxy over shellac has this been confirmed? would the Epoxy yolk really come loose producing a million tiny rattles!?