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I bought a 1967 D18 that has a botched up refinish.
The back had big patches that had been sanded through to the wood , looked kinda like a patchwork quilt.
I have sanded that back to bare wood again.
the sides and top have also been cleaned up to the original finish and I'd prefer to leave them as they are and just overspray.
as the back is now bare wood I'm wondering if anyone can get me in the ballpark of a stain color that martin was using in that era

This is a 2 stain process , you use red mahogany and brown mahogany , red first , then brn seal , then fill then seal then finish

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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

Thanks very much John.
I was hoping you'd reply

Didn't Martin use a permanganate chemical stain for that vintage?

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I'd suggest going one step beyond John's two step suggestion and to mix a custom color using brown and red mahogany (Stew Mac) concentrate into alcohol along with a touch of amber and perhaps even a dab of green to match the exisiting color.
Problem is that the lacquer has turned quite amber and tones everythng so simply mixing a stain color minus the finish color won't match.
Better to mx all the colors and test until the new color will match the old when it's under a new clear finish.
Also the filler becomes an important part of the mix as John mentioned. The walnut colored Stew Mac product is a fairly close match for the Behlen products that were used originally. The original finish was most likely Sherwin Williams T75-C10 gloss lacquer.

Also, I'd suggest sealing with a wash coat of shellac after staining, to keep the filler from staining the wood.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Will the staining red then brown mahogany work with Z-poxy over top or is it better with a water or oil based filler? The reason I ask is my buddy who is building in my shop is doing a Mahogany OM, which is beautiful 1/4 cut Honduran but will be real boring without stain.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I called martin this morning about the permanganate stain question. After talking to Customer service Lon and a few others , I called a past plant manager that worked at Martin during the later 40's to the 70's and he said the used the 2 stain method . The only thing he could recall and this was backed up by Martin this morning is that they tried a water stain but that never made the cut.

Martin does not use a water based filler , the finish process is sizing , stain seal fill seal and they use vinyl sealer then base coats of about 8 coats of lacquer ( this may have changed with the new booth ) then level sand 3 more finish coats level polish and buff.

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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

Yes, all the stain that I ever got from Martin (early 80's?) was the alcohol solvent dye type.
Filler as well was thinned with mineral spirits (or naptha). Vinyl sealer started in the 60's I think. No water base anything.

One thing you might want to do however as you apply your stain is to first flood the raw wood with pure alcohol, this will prevent the stain from "grabbing" and allow you to darken and tone the surface to the right degree. The best attribute of the alcohol dye stain is this ability to subsequently darken the surface with repeated applications. In the case of tryng to match the sides of your repair you may or may not want to seal before filling.

Thank you all for all the great info
The knowlege base here if unbelievable

When I was out at Martin for training , the filler was as Dave informed , a mineral paste filler that was pretty dark and with a texture not unlike hershey's syrup. The foreman let me know they added a few drops of naphtha to the mix to aid flash time . I use Pore o Paq filler and do the same technique of application they do.
The sides are applied a liberal amount of filler and worked in with a stiff brush and allowed to flash. ( takes a few minutes ) then using a buffer the filler is "polished" into the pores. As the material fills you will see balls of filler work off and the buffing pad gets a thick coating. This seems to help force the filler into the pores.
I do 2 application then seal. You can do this by hand but that buffer helps. Be sure you do this in an area you cover or that you don't mind filler splattered on.

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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