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Since I am getting ready to use a product new to me, namely Cardinal Lutherlac, I thought I would do a test. I took a strip of wood and divided it into 3 sections. I put Zpoxy on all 3, dried a day then level sanded, then 2 coats of vinyl sealer on section 2 & 3. They were done 1/2 hour apart. I waited an hour then roughed up the sealer on the 3rd section only with scotchbrite. Then brushed on 5 coats of nitro on the whole thing alowing plenty of time between coats, several hours actually.

Five days later I did a hatch test, scoring lines about 3/16" apart making a tic-tac pattern. I used reinforced shipping tape over it pressed firmly down. I waited 15 minutes letting it get a grip then I pulled it off. Nothing, no finish came with it. I scored deeper and tried again. Still nothing.

I went to the knife, scraping each panel. My results:

1. I don't know how to do a cross hatch test
2. All 3 sections had good adhesion
3. The section with just zpoxy and nitro was notably poorer than the other 2 but still not bad
4. The section that had the roughed vinyl sealer seemed to have a slight edge on adhesion, but just slight
5. I think I'm going to like Cardinal

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Joe Beaver
Maker of Sawdust

Thanks Joe. That's interesting. I'm a little suspect of the bond between Z- Poxy and nitro. I have used z-poxy on porous bodies but I never use it on necks. I notice when when I sink an awl into the butt wedge (ok, that sounds wrong) of the nitro Z-poxy I get a 1/8 - 3/16" round delamination of the finish. When I sink the awl into the neck with only nitro I see almost zero delamination. I've also had small delaminations on binding edges where I didn't even realise I bumped a corner. That was after 3 or so weeks cure time. FWIW

What do Martin and Gibson use for pore filler? I think they both use nitro don't they?

I think I'll go the vinyl sealer roughed with scotchbrite under the nitro. I sure don't want to see delamination down the road. I had that once and man, what a mess. left a bolt on neck on the body for a few days and when I pulled it, there it was, delamination.

I think Martin and Gibson have made a transition to a urethane finish for a lot of there models. They still use nitro on the higher end ones I believe.

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Joe Beaver
Maker of Sawdust

Last check -- Martin uses catalyzed nitro lacquer in the factory in PA. Paste pore filler, similar to Pore o Pac, burnished in with a high speed wheel (at least on the necks). Mexico factory uses wipe on poly on some models.

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Ken Cierp

http://www.kennethmichaelguitars.com/