Pore Filling

[Bob Webster]

Surely someone else has torn their hair out over this (see picture). How about weighing in with your favorite method, its merits and frustrations? Surely we can get a food fight going that will make us forget about French polish, etc.

[Bob Webster]

"Kudos to you for trying to get a fight going :)" Well, I sure as hell tried, but this group is too mellow.

As for favorite methods, after I'm done with Heide Klum, I fall asleep dreaming about your favorite method. God, think about it. A classical guitar with a maple neck, cypress body, and spruce top, ebony faceplate and bindings. Not a pore on it. Can't even say that for Heide. Okay, I'm outta here.

Cheers,
Bob

[Penql]

I like the way you think Bob :)

Seriously, run a fine scraper over some african blackwood, and then try to tell me you don't feel dirty if you even think of putting a finish on there...

My last completed instrument (see my profile page) has over 50 species of wood, and no finish except carnauba wax. That nobody could play it (let alone afford to buy one) is beside the point :) The bow is blackwood, it smells like espresso and chocolate and cuban cigars when you scrape it. Pore filler? Meh.

Heide Klum you say...

[Penql]

P.S.

English Sycamore
Chakte Viga
Macassar Ebony
Olive (yeah, that tree in your neighbour's yard, claim that puppy, dry for 2+ years, forget Heide)

[Bob Webster]

I know. I have some old scraps of Brazilian that I take out once in a while to just smell and reminisce. I'd love to build one guitar with African blackwood but I'm still short the downpayment. Some day. What is Chakte viga like? Cook Hardwoods in Grant's Pass, OR, was suppposed to have some available in December.

Bob

[Penql]

"What is Chakte viga like?"

Like pernambuco, only yellow. Itchy sawdust. Heavy, tiny pores, works like cocobolo (itchy like that) but not really oily. Machines nicely, seems to bend well like pernambuco (I've only tried a bow sized stick). Interlocked grain but very tightly like ceylon satinwood has. Ages to a dark amber/pumpkin color.

[Ronnie Nichols]

Having a background in the auto body repair and painting business (old school), I have always leaned toward lacquer finishes. I agree with a lot of the luthiers on here that filling the pores is a real challenge. I've never found anything that I was 100% pleased with for rosewood and mahogany. I've tried the old fashioned paste wood fillers and the water based wood fillers. It seems like I still end up applying a lot more finish than I really want to because of the pore problem. It seems like you must choose whether you want to minimize the finish and maximize the sound or maximize the finish at the expense of losing some volume and tone. I've tried several different approaches but I'm still searching. I have not spent much time on french polishing. I'm sure it has its advantages. I prefer finishing maple because it doesn't take as much finish to achieve the glass-like appearance, but it just seems that rosewood makes a better sounding box. I've observed that some of the Blueridge Guitars are quite a bit heavier than others. Since they all appear to be built pretty much the same, I have suspected that the finish is the difference in weight (and possibly the tone, too). I suspect that they use some high-build urethanes to achieve the pore-filling.
Ronnie Nichols

[Bob Webster]

"It seems like I still end up applying a lot more finish than I really want to because of the pore problem. It seems like you must choose whether you want to minimize the finish and maximize the sound or maximize the finish at the expense of losing some volume and tone."

That's really it in a nutshell. Robert Ruck, a classical builder in Eugene, OR. puts out fabulous sounding guitars that are also pieces of art from the standpoint of fit and finish. He uses Elmer's water based indoor/outdoor paste filler colored with acrylic paint for pore filling backs and sides and follows it with a sprayed catalyzed varnish (don't know the brand). He claims that he can get a very thin finish with his method that gives tonal quality equivalent to French polish. I've played several of his guitars and certainly would not dispute his claim. My guess is that the trick is aggressive rubout after complete cure of the finish, but magically knowing when to stop.

Bob

[Ray Hodgson]

In my opinion Z-Poxy "Finishing Resin" is by far the easiest most economical way to perfectly fill pores in tonewood.

A quick search on the OLF or MIMF will turn up some great info on this product.

Ray

[Bob Webster]

Yeah, Ray, I'm on my second set of Z-poxy now. The only downside to the stuff is that it's not quite viscous enough to stay put. The result for me is that if I try to fill both the sides and the back in one go, the stuff runs a bit down the sides. Minor inconvenience, though. I do find that it usually requires two passes to really get the surface flat.

I'm not one of those folks that tries to get a really smooth application of the epoxy and then sand carefully to within a micron of the wood surface. I pretty much slop it on. I do alot of scrubbing around just to make sure that it's getting INTO the pores and not just bridging them. After it's cured, I remove the excess using a cabinet scraper. I then sand out to ensure that I'm back to the wood surface and seal with shellac to get going with the French polishing. I still find, however, that the Zpoxy will shrink back just the tiniest bit after a few months. Overall, though, a really good result.

Bob

[Russell Vance]

I lost concentration after the bit about pore filling Heidi Klum...Knowing that aging luthiers are a lascivious bunch I suppose the merits of spraying on, or rubbing in, an oil finish on her will get some traction here........Rusty.

[Bob Webster]

Rusty, you dirty old POME, clever enough by half. Everyone knows that the secret to life is just good surface prep. I think, however, that the alternatives you suggest might even push hardcore shellac sprayers into the French polish camp. Hello..., Jim Bancroft....?

Anonymous