Acoustic Guitar Construction

I French polish, with no buffing or polishing compounds. Traditionally that is the way they are left. I mostly follow the way that I learned from watching a Robbie O’Brien online class. I have also read the Milburn brother's description and took a short course with Cyndy Burton, who originally taught the Millburn's. Although their technique is much different now than Cyndy's.

As for a schedule ... I do not really follow a schedule. Rather I use a process. The process is somewhat flexible in terms of how long I go during a session and how many sessions I do. Also with French polish you can always go back a step when there is a problem. I once asked Robbie O’Brien how long one should go when FPing and he said right before your arm is going to fall off.

After I pore fill the instrument on the back, sides and neck (I use between 2 or three sessions of zpoxy ) I give the whole guitar about three thin padded on coats of 1lb cut amber shellac that I make from LMIs amber flakes. What I will describe is bodying and spiriting off. My pad (muneca) is a 4"x4" high thread count white cotton strip. I use lambs wool as stuffing, others use cotton or wool knit.

I start applying body coats with the same 1 lb cut of shellac. I put about 6 "sessions" worth of polishing on during the bodying stage. Each session for me includes charging the inside wad in my muneca. I actually dunk a wad of lambs wool in the shellac and squeeze most of it out. I place the wad in a 4 x 4 piece of cotton. Fold and twist until I can get a little shellac to squeeze out. I back off the twist a bit and blot the muneca off as I do not want anything resembling a drop or drip. For each session I start by lightly appling the shellac with long ways strokes. I keep applying until things get a little sticky. At that point I put a drop of oil (I use olive oil) on the muneca and use small swirls to cover the surface I am working on, usually a few times around the surface I am polishing. As the pad dries out and it is harder to swirl, I get rid of the swirls with relatively hard long ways strokes until the surface looks pretty good and there are no swirls and very few streaks. Through all of this the pad should not stop on the guitar. Also when doing the long strokes pretend you’re an airplane coming in for a smooth landing; bumping the edge with a charged muneca can ruin your day with a drip on the adjacent surface.

After enough bodying sessions (6 or so for me) I spirit off the polish. The pad is charged with only alcohol (either DA or 190 proof everclear); I dunk a wad of lambs wool in the alcohol and squeeze most of it out and place it back in the cloth. Not so much that it will drip. I do long strokes with the grain, very gently and evenly across the instrument surface until the pads starts drying out. As it is drying out I am applying more and more pressure burnishing the finish. I watch the alcohol evaporation trail to know when I should apply more pressure and when the pad is dried out. I do this about three times. I basically do this until I am happy with the look.

While working if it gets hard to do a session or the finish seems soft, just leave it for the day or at least a few hours.

If you ever want to FP watch Robbie O’Brien's FP online class. You almost see it in real time. I also read Milburn's description http://www.milburnguitars.com/fpbannerframes.html. They over complicate their description a bit. I tried to pore fill their way on my first classical and had little success, although I have heard they have switched to epoxy. But their FP description really is excellent and worth reading.

Very clear and helpful John. Thanks.

Why doesn't the shellac alone fill the pores, I wonder?

deadedith wrote:Very clear and helpful John. Thanks.

Why doesn't the shellac alone fill the pores, I wonder?

A shellac finish is so thin by the time you were finished you would just have shellacked pores nearly as deep as when you started. The shellac will go in the pores but a great volume of alcohol evaporates leaving just a thin coat of shellac.

Using pumice you can fill the pores with a mixture/slurry of shellac, wood dust (sanded off the wood with the pumice) and the pumice itself. I did that the first time I French polished a guitar and had good results. It took a lot of time though and the pores are a bit opaque, but nicely colored with the wood dust.

I think Robbie said that his favorite method of pore filling is shellac and endgrain sawdust. I didn't have much luck with that, though I would like to see it done.

deadedith wrote:I think Robbie said that his favorite method of pore filling is shellac and endgrain sawdust. I didn't have much luck with that, though I would like to see it done.

Robbie used spackling with black tint in the online class. I have not tried it.

I think Robbie's recommendation is a little misleading, pore filler for "black lacquer" piano finish requires no transparency or clarity. It merely fills the voids and latter gets covered with an opaque finish (painted) So yes final coat (fine forumula) drywall joint compound wil do the job in that instance. The commercial equivalent to this is "Timber Mate" Again, to my eye the final finish lacks clarity, Behlens water borne pore filler has the same problem. On the other hand the Behlens oil base filler does enhance the look of the wood.

kencierp wrote:I think Robbie's recommendation is a little misleading, pore filler for "black lacquer" piano finish requires no transparency or clarity. It merely fills the voids and latter gets covered with an opaque finish (painted) So yes final coat (fine forumula) drywall joint compound wil do the job in that instance. The commercial equivalent to this is "Timber Mate" Again, to my eye the final finish lacks clarity, Behlens water borne pore filler has the same problem. On the other hand the Behlens oil base filler does enhance the look of the wood.

I agree, I would rather have a transparent filler. From what I remember to his eyes the black pore filler darkened the IRW giving it more of a BRW look.