Official Luthiers Forum!

I am about ready to pore fill my mahogany dread, I am wondering how carefull I need to be in avoiding any z poxy on the spruce top? is this a concern ?or is it easily removed ( if so, how? )? thanks jody

Some people zpoxy spruce tops to pop the grain and/or colour same. I only zpoxy the backs and sides of my instruments. When applying zpoxy to the sides I have the guitar top down so that if any runs off the sides it will drop onto the bench rather than get on the top. Occassionally a bit of zpoxy will get on the bindings but its easily sanded off once the zpoxy has set or sometimes Ill get a bit of alcohol and wipe the zopy off being careful not to smear it onto the top.

Cheers Martin

Some folks think that zpoxy and tops don't mix due to the extra mass that it adds. I use one thin coat (50:50 DA/Zpoxy wiped with a rag and lightly sanded when dry) as a toner because I like the amber color it gives to spruce. I also like having my wooden rosettes filled using the same technique as the rest of the guitar, especially when I use the same wood for other accents. Back to your question though, drips can be wiped off while still wet with DA or easily sanded down when dry. So, be careful, but you don't have to go overboard.

I agree with Bob and Martin. I also like the slight amber color that epoxy thinned with DA can provide a top.

As Colin has said very correctly epoxy is not intended to be a finish so he and many others sand it back and only leave it in the pores. This also means that they won't use epoxy, thinned or otherwise on tops either.

If you get some on the spruce top it sands off very easily so no worries.

Excuse my ignorance.... DA?

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

So sorry Alain - denatured alcohol

Ah! Thanks.

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

Thanks for the help guys,I am planning a french polish finish , at this point I dont want to color the top, not at least until I see how the Z-poxy changes the pitch of the back, I am assuming it will raise the pitch some... time will tell me ,... Thanks Jody

Brush egg white on the sanded top, and when dry, lightly sand to take off any raised grain. Then French polish.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Colin, do you use the whites as they come out of the egg? I have a vague memory of a recipe where the whites were whipped, then the remaining liquid used(or something like that )....thanks Jody

Straight from the egg, just separate it from the yolk and brush it on.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Hi Colin

I've read about using egg white on spruce prior to French polishing before. What does it actually do for you in terms of the eventual finish you end up with?

Thanks

john

Jody,

I french polish all of my instruments and use zpoxy to fill on my steel strings and pumice on my classicals. No reason I use pumice on the classicals apart from keeping with the low tech approach I take to building the things.

Colin , when you use the egg whites on a top, do you mask off where you will be glueing the bridge first ? or fo you glue to the white coated wood ? thanks Jody

John,

If you will remember back a generation when your mom would size cotton shirts and pants before ironing them. She did so with distilled water and a very light starch mixture. This would swell the cotton fibers and the starch would stiffen them. This is sizing. Egg whites are used to size the spruce as well as seal it. The egg whites will raise the grain, swell the fibers and make the top surface stiffer and more resilient. In my opinion it makes the spruce slightly less susceptible to denting from light impact.

Jody. The bridge is no issue. I know Colin glues his bridge on before he French polishes but I am not sure he glues it on before he sizes the top with egg whites but i am guessing so.

My self, I size right after prep sanding to 220p and before I start to French polish. I don't glue on my bridge till after I am through with the finish and I scrape back the finish to wood to glue on the bridge. I find it simpler to FP with out the bridge or fretboard extension in place. This allows my spiriting strokes to be full length and with the grain everywhere. But that is not an absolute necessity. Just what works for me.

Can you put other finishes on top of egg whites? Water-based lacquer?

_________________
A higher purpose for wood.
Rich Smith
Issaquah, WA

With out a hitch in most cases. but if concerned just seal the egg white sized top with shellac and you are good to go.

Michael is right, I always glue on my bridge before finishing so that I can give the top any final tuning with the strings on, common practice in classical building and works well for me with steel string as well. French polishing the top is no problem with the bridge on. I glue the bridge onto the untreated top, but egg white should have no effect on glue adhesion, especially if the gluing position is scraped or sanded.

As well as French polish I have also used a variety of oil based finishes over the top of egg white with no problem, but as Michael says a washcoat of shellac should ensure that you can put any finish on top of the egg white size. I use it on all of my tops.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Michael,

Thanks for your reply. I took a 2nd grade spruce top and gave the egg white a try on one-third of it. On another third I applied two 1# cuts of blonde shellac, and on the other third I just left it as is. What was surprising to me is that the third of the board with the dried egg white definitely has more character/depth in the way it looks as compared to the other two parts of the board. The silk really stands out, and that portion of the top just looks better. I imagine this would have to make a difference in the way a properly applied FP finish would look as well?

john

I had been aware of sizing wood with egg whites for decades. I had never given it a try. Some 4 years ago someone on this forum convinced me to give it a try. I believe it was Colin. I was amazed at the affect the egg whites had on spruce. Like you said any silking and depth appearance just jumped but the thing that really got me was how much firmer the top surface after sanding the raised grain back down.

Form that day to now I have sized every softwood top I have used.