Official Luthiers Forum!

I'm a recent convert to the ways of Z-poxy. Tried hardware store epoxy for filling, hated the way it flowed and sanded; now have Z-Poxy (and West Systems with 206 hardener for general stuff) in the house, and I'm growing to like it more and more. Having tiny little mixing cups (disposable) certainly helps, and the more I use it, the more I like it.

I'm still experimenting with the best way to get the fill I need with the stuff, though. Right now I'm filling a carved khaya mahogany electric (annoying because of the curved surfaces, making it difficult to sand level/evenly) and a pair of swamp ash bolt on electric bodies (annoying because, well, huge pores). What's worked best for me so far is to start with a single undiluted coat of z-poxy, scuff sand, then apply a second coat of thickened (small amount of silica filler - have System 3 stuff from the ClearCoat I bought a while ago - threw out the epoxy because the hardener mutated on me, went solid and ate through the bottle it was in...) z-poxy on top, and level sand that. Any slight sand-throughs that show weird colour are equalized with a final coat diluted with about 25-30% denatured alcohol wiped on with a scrap of cotton.

Thing I'm currently running into/don't have a great solution for yet: Application - right now I'm using an old credit card for the main coats, but levelling it tends to leave a few too many streaks/ridges that are a pain to sand on non-flat surfaces (and not that much fun on flat surfaces). Tried wiping as well, but that seemed to pull stuff out of the pores.

Anyone care to share their favourite tips, tricks or techniques for working with the stuff in terms of pore filling?

Mattia I like Z-Poxy finishing resin better than SIII because the mix ration is not as critical but both are great products.

For the flat surfaces I use a credit type card too but instead of using it like a squeegee I use it initially with the card fairly well bend to mash the epoxy into the pores. My motions are at 45 degrees to the grain and later in all directions and I am pressing/mashing the epoxy downward as I go. Once I have an area of say 6" X 6" done then I use the card as a squeegee to squeegee off the excess and smear it onto the next area that I am going to do.

For irregular surfaces such as necks I wear a latex glove and use my finger.... to apply the Z-Poxy. I work it again in all directions and then use my finger to heard/squeegee the excess into the next area that I want to do.

For level sanding I use foam blocks that are of differing thicknesses giving them differing flexibilities. A thick block is used on the mostly flat areas and a thinner more flexible block is used on the neck. Of course the blocks are wrapped in sand paper.

For the final coat to cover up the sand through areas I use a 50% mix of DA.

You can sand it back all the way to the wood everywhere and just leave the Z-Poxy in the pores too. This evens up the color but you lose the pop effect that epoxy does so very nicely.

Necks take me one coat to do and bodies seem to always take two coats.

I have been doing 2 or more coats with a razor blade and sanding them both back and then 1 final coat thinned with alcohol. The final coat I do in long single passes and overlap very little. I then scuff sand this coat with 320 before starting the finish process. I am using the west systems.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

System 3 clearcoat. I have a box of old business cards. They work well. when those run out I'll go back to squegee (sic). you can get automotive windshield wiper but I have been concerned about leaching the black rubber. Instead I have used inexpensive "shower" sqegee from the dollar store. I find I can get smooth coats with business cards using long straight strokes following the wood grain and getting the excess off. I use no thickener or dilution. It is viscous enough to withstand gravity, so I can rotate the piece and do all sides with one mix. The system 3 mix is easy to get with medical syringes. I use a 60ml for resin and 20ml for hardener and carefully stick to the 2:1 ratio. I like it. I have some that is three years old and no denaturing or bottle damage. I keep it at basement temperature, only light is flourescent lighting. No direct sunlight.

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Greg
http://garibaldiinstruments.com/