Epoxy Pore Filling Part 3: Prep & Application of Third Coat and Prep for Finishing

[2herbie2]

Thanks Todd for a really excellent and thorough series on pore-filling with Z-poxy. Your demonstration really takes my guesswork and first time jitters away. I used 2 shellac sealer coats under the Z-poxy and it worked well on Indian RW and Spanish Cedar. I was concerned with Z-poxy possibly causing RW bleed over light maple bindings so I used CA over the bindings first, but maybe it would have been O.K. to use the z-poxy first on the bindings alone as you suggested to @eXkillswitch11.

[MDLuthier]

@2herbie2 I don't find the shellac sealer is necessary - standard untwined z-poxy or West works just fine for the initial coat.

[eXkillswitch11]

will z poxy cause purple heart to bleed into other woods glued next to it?

[MDLuthier]

@eXkillswitch11 Not a problem...if in doubt, seal your bindings and purrs with epoxy before the main part of the body...a gloved finger makes a great application tool.

[madhattr88]

love your video. i did exactly this, and now would like to finish with tru-oil. think i'll have any problems? is a quick coat of shellac (after the z-poxy, before the Tru-oil) a good idea? is it necesary?

thanks!!!!!!

[MDLuthier]

@madhattr88 Z-Poxy, like all other epoxies, can produce an amine blush if there is unreacted resin or unreacted hardener. This amine blush can interfere with finishes which dry by polymerization, such as oils or varnishes. I suggest a coat of shellac between z-poxy and truoil or other varnish. Another alternative is to wash the amine blush off the surface before finishing with drying oils or varnishes; however, it can be difficult to verify that all of the blush is removed, so shellac works.

[cowdudeable]

Is this epoxy pore filler suitable for waterborne laquer? And secondly, are there plans for that foan filled clamp you used to hold the guitar body to sand the sides?

[MDLuthier]

@cowdudeable You can pretty much use anything over z-poxy, including lacquer, WB lacquer or urethans, cat poly, polyester, french polish/shellac, or varnish. Some user shave reported some long term issues with TruOil over Z-Poxy, but others have had success. The clamp is a guitar trojy, and plans are available on Official Luthiers Forum...search for ;guitar trojy' to find the thread in the archives.

[steffa4]

Amasing! Thank you.

[MDLuthier]

Not mentioned, but if the final coat of epoxy is difficult to squeegee to a very thin, even coat, it can be thinned by 5-10% by volume with denatured alcohol. Thinning beyond 10% may result in a softer cure...not what you want. Epoxy pore fill is suitable for nitro, nitro over vinyl sealer, cat polyurethane, etc. Always use a compatible sealer and topcoat, or use a barrier coat of shellac to seal things.