Official Luthiers Forum!

My Martin Mahogany guitars have a black grain integrated in. Are they using an Ebony green filler, or is that the way mahogany comes out naturally?

Also, do you guys use green filler on the spruce top?

No filler on tops and what Martin has used, currently uses, etc. is generally not what we or small builders use. John Hall who is a member here is a good one to ask if you want the current scoop on what Martin is doing but again most of us use something different and many of us had trouble making what Martin uses for pore filler work. I found what they were using 20 years ago to be a nightmare to make work in a small shop, burlap, etc who needs it.

I used epoxy with great results even nearly 20 years out now, no shrinking in the pores (yet).

Pore filling may be something in Lutherie that does not scale well meaning what the big guys use does not translate to something easy for us to use. YMMV AND welcome to the forum Thomas.

I am apparently alone in this but I use oil-based, paste wood pore filler, which is what Martin uses. I find the this filler is no harder to use than most other fillers. I buy neutral colored filler and tint it with colorants. On mahogany I tint the filler to a dark chocolate brown. For rosewood I tint it to a darker shade that is sort of a blackish brown. Hesh is correct, in that the filler is a bit hard to use until you learn a few tricks. Always use the filler after applying a couple of coats of sealer or thinned lacquer. Also, don't let the filler dry too much before wiping it off. I don't use burlap, but just a small piece of an old terry cloth towel. Don't wipe too much or you will remove the filler from the pores. Let the filler dry for 48 hours before you start apply finish.

Martin uses a comercial product Mineral spirit based not unlike pore o paq it is stained with Maple #55
you can get a similar result using dark walnut ( MinWax ) or use Jeff Jewitts toners sold at LMII and stewMac
They use a few drops of Naphtha to help flash the filler

so Stain first seal Vinyl sealer 1 coat
fill 2 applications and buff in well scrape binding
seal another coat scuff sand then apply nitro

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Using burlap to remove oil based paste fillers does make the work go quicker and seems to remove the excess and leave the filler in the pores. It's getting harder to find old burlap bags so you may have to resort to - buying - burlap from the fabric store. As Barry mentioned, don't let the filler dry too much before removing the excess. For woods with large open pores a second application (after the first dries) may be needed.
On woods that don't need a colored filler to get the look I want I usually "fill" with epoxy.

Hesh mentions that small shops/individual builders may not be well served in trying to mimic a factory's techniques. That applies to construction, too. Factory building, I think, concentrates on minimizing the parts count and minimizing construction operations. That doesn't mean that it's to a builder's advantage to copy the factory.

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Peter Havriluk

Thanks, John.

I should’ve been more specific in my question. I’m more concerned with getting the color to match my martin guitar. I am not concerned with what particular product they use or what tools they use. I’ll use some dark walnut grain filler from stew Mac. I found another post somewhere else that claimed they stain the wood with a mixture of red mahogany and dark walnut.

I really like the colors they get on mahogany.

If you want the Martin look then you'd be better off using the exact products they use. You would never get that color with an epoxy filler. I like Aqua Coat too but it would also not be good for the Martin fill.

I found that Minwax special walnut ( redish ) followed by Minwax dark walnut gave a good color match to the martin
as for the filler
You can mix dark walnut into the filler I found aqua coat worked well to give you the dark pore filler look
you can also use dark walnut Pore o Paq it gets it pretty close

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

In the good old days, I used call Martin and they would pop pints of filler or stain in the mail in plastic bottles. I did that for a bunch of years. It was naptha based filler, tinted for rosewood or mahogany. The application was the old apply it, let it almost dry, and they scrub off the excess with burlap. It was not difficult to do. One big advantage was that the colored filler showed any sanding flaws before you went on with the finish. A big disadvantage was that you had to be cafeful about sanding through to bare wood during the finishing process. As a filler, I think it worked better than Aquacoat or other water base fillers that we use now. I currently use Aquacoat, because of it's colorless properties, and I don't care much for it. Always looking for a better product.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Thanks, John

Currently using Cardinal's Rosewood oil-based filler on Mahogany necks. I really like Epoxy as a pore-filler but the Cardinal Rosewood filler makes mahogany necks look vastly superior. It really is no contest. Let it dry for at least 3 days after pore-filling before moving to the next step. Like everything else, there is a bit of a learning curve but it is actually very easy to use.

If anyone making recommendations has some pictures, I'd love to see examples.

Thanks

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Brian R, Wood Mechanic
N8ZED

Here is a replacement 00-17 mahogany body for an 1931 Martin neck that got some old LMII oil based filler.

Looks great!
I’ve searched oil based filler and come up empty.

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wah
Wah-wah-wah-wah
Wah

Other terms for this filler are "paste wood pore filler", and "silex filler".

Here is a link: Pore-O-Pac

Try Mohawk Finishing Products.