Pore Filling Vs Multiple Coats.

The Achilles' Heel of Luthiery
Scott Novak
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Pore Filling Vs Multiple Coats.

Post by Scott Novak »

I've always wondered why people fill the wood pores instead of just using multiple coats of finish until the pores are filled. Could someone please enlighten me?

I've used multiple coats of very thinned out polyurethane to fill the wood pores of oak and it turned out very well. Could you just use multiple coats of nitrocellulose lacquer to fill the pores of mahogany?

I've got a mid 60's Gibson Melody maker that I want to refinish which has a mahogany neck and body.

Scott Novak
tippie53
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Re: Pore Filling Vs Multiple Coats.

Post by tippie53 »

multiple coats have a weakness in that they shrink back over time. I thought the same thing but have learned it doesn't work. Even on french polish the old timers used egg white and dust to fill. I found that LMI's water based filler and Auqa Coat work well.
you best finish will only be as good as your base prep.

the other benefit of sealers and filling is you get to get a better finish with thinner coats.
John Hall
Blues Creek Guitars Inc
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Diane Kauffmds
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Re: Pore Filling Vs Multiple Coats.

Post by Diane Kauffmds »

I wondered the same thing Scott. I used shellac on my first build, so much that it filled the pores of the Peruvian walnut. About 6 months down the road, those pores started to reappear. The shellac had shrunk into the pores, resulting in their reappearance.

I'm sure it's possible to completely pore fill with a finish, but you'd have to use a lot of finish, which would be unattractive. .

Nitro, like shellac, shrinks over a period of time.

What I like to do is to put 2 seal coats of shellac on the mahogany, then pore fill. Aqua coat works very well, as well as System 3 or Zpoxy. I use shellac for 2 reasons:

1. It keeps the pore filler on the surface of the wood, filling the pores faster with less filler.

2. Shellac imparts a beautiful warmth. It also brings out any figure in the wood, making it almost 3D, unlike any other finish. Shellac plays well with all other finishes.
ruby@magpage.com
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Re: Pore Filling Vs Multiple Coats.

Post by ruby@magpage.com »

Remember too, Scott, that pore filling is not necessary. I have seen plenty of older high-quality instruments without a complete pore fill, or any at all.

Ed
Ed M
Scott Novak
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Re: Pore Filling Vs Multiple Coats.

Post by Scott Novak »

Thanks for your information.

It appears that it's a simple matter of shrinkage. I'm guessing that I got away without pore filling oak because polyurethane probably doesn't shrink much. I also used about 30 very thinned out coats of polyurethane so it didn't take very long for the solvents to leave the varnish.

I've never used nitrocellulose or shellac finish before so I've got a bit of learning to do.
tippie53
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Re: Pore Filling Vs Multiple Coats.

Post by tippie53 »

I will say this
if you want a gloss finish you will have to fill
if your doing a satin you can get away without
John Hall
Blues Creek Guitars Inc
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MaineGeezer
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Re: Pore Filling Vs Multiple Coats.

Post by MaineGeezer »

You'll get a better result if you pore fill.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Diane Kauffmds
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Re: Pore Filling Vs Multiple Coats.

Post by Diane Kauffmds »

Pore filling makes French polishing easier, because of the smooth surface. It makes it go a lot faster too; the shellac builds faster. I pore fill, even if I plan a satin finish.

I frequently do the back and sides to a high gloss, then make the top and neck satin. Not all woods need to be pore filled. Spruce, maple, cherry, birch, and some others, have closed pores and don't require pore filling.

The decision to pore fill is an individual decision. In my opinion, pore filling produces a more professional looking guitar, so I pore fill my guitars.
Scott Novak
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Re: Pore Filling Vs Multiple Coats.

Post by Scott Novak »

I really like the natural color of the mahogany on this guitar and I don't plan to stain it.

Do you normally try to match the color of the wood with the pore filler or go lighter or darker to contrast the wood color?

I remember seeing a very old Epiphone solid body guitar made from mahogany that appeared to use a lighter color pore filler than the green finish color.
Diane Kauffmds
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Re: Pore Filling Vs Multiple Coats.

Post by Diane Kauffmds »

Scott Novak wrote:I really like the natural color of the mahogany on this guitar and I don't plan to stain it.

Do you normally try to match the color of the wood with the pore filler or go lighter or darker to contrast the wood color?

I remember seeing a very old Epiphone solid body guitar made from mahogany that appeared to use a lighter color pore filler than the green finish color.
I almost never stain or change the color of the box. Aquacoat dries crystal clear and is probably the easiest to use. Seal the mahogany with shellac first.

I also use System 3 Epoxy pore filler which is clear. But, I make it a policy to seal the wood first.

This photo is of a mahogany guitar, pore filled with Aquacoat.
PicsArt_02-17-03.06.20.jpg
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