Official Luthiers Forum! :: View topic - West System 3 epoxy pore filling over a coat of shellac?

Ok. That's fine. I have other pore fill options.

So when you dye the backs/sides, but have light (herringbone) purfling, what is your method for keeping the purfling from getting stained when applying the epoxy pore fill? Do you do a light sealing coat before you really start dragging/mashing it around?

The quick and easy, though heartbreaking, answer is NOPE. Shellac will bond to epoxy but not the other way around. So you'll have issues with your pore fill.

Pwoolson wrote:

The quick and easy, though heartbreaking, answer is NOPE. Shellac will bond to epoxy but not the other way around. So you'll have issues with your pore fill.

Question. Why does the order matter?

Author:	Linus [ Tue Mar 22, 2016 7:33 am ]
Post subject:	West System 3 epoxy pore filling over a coat of shellac?
I'm in the finish stage on an acoustic. A mahogany body with a water-based stain. I put a coat of Royal Lac shellac over the stain (once it had dried). I haven't done my pore fill yet. Can I use West System 3 epoxy OVER the Royal Lac coat? Then once the pores are filled I'll build up more coats of Royal Lac doing a French polish. Any bonding issues?

Author:	Pwoolson [ Tue Mar 22, 2016 8:47 am ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
The quick and easy, though heartbreaking, answer is NOPE. Shellac will bond to epoxy but not the other way around. So you'll have issues with your pore fill.

Author:	Linus [ Tue Mar 22, 2016 9:52 am ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
Ok. That's fine. I have other pore fill options. So when you dye the backs/sides, but have light (herringbone) purfling, what is your method for keeping the purfling from getting stained when applying the epoxy pore fill? Do you do a light sealing coat before you really start dragging/mashing it around?

Author:	WilliamS [ Tue Mar 22, 2016 9:02 pm ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
Just to mention: Royal Lac doesn't act exactly like regular shellac and might not be the best to seal with. I believe that when using RL it's suggested that you seal with either their Seal Lac or regular de-waxed shellac. I know that, with the way it cross-links and hardens, it's not repairable the same way regular shellac is after it's cured: new coats don't burn in and you have to scuff sand for a mechanical bond to re-coat/repair (again, that's after it's cured). Not really sure but I wouldn't be surprised if something related to those characteristics may contribute to it not being the near-universal sealer/tie coat the regular dw shellac is. IDK if it'll cause you any problems or not but thought it was worth mentioning.

Author:	johnparchem [ Tue Mar 22, 2016 9:49 pm ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
Linus wrote: Ok. That's fine. I have other pore fill options. So when you dye the backs/sides, but have light (herringbone) purfling, what is your method for keeping the purfling from getting stained when applying the epoxy pore fill? Do you do a light sealing coat before you really start dragging/mashing it around? I have done this with maple binding and cocobolo. It took a bit of extra time but I first applied a thin layer of epoxy using a rag over my bindings and the center strip in the back. I let it cure a bit and proceeded to pore fill the rest of the guitar. After the first application I do not get color bleed.

Official Luthiers Forum! http://www-.luthiersforum.com/forum/

West System 3 epoxy pore filling over a coat of shellac? http://www-.luthiersforum.com/forum/viewtopic.php?f=10101&t=47500	Page 1 of 1

Author:	Linus [ Tue Mar 22, 2016 10:18 pm ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
Thanks!!

Author:	Mike OMelia [ Tue Mar 22, 2016 11:29 pm ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
Pwoolson wrote: The quick and easy, though heartbreaking, answer is NOPE. Shellac will bond to epoxy but not the other way around. So you'll have issues with your pore fill. Question. Why does the order matter?

Author:	Pwoolson [ Wed Mar 23, 2016 7:50 am ]
Post subject:	Re: West System 3 epoxy pore filling over a coat of shellac?
Mike O'Melia wrote: Pwoolson wrote: The quick and easy, though heartbreaking, answer is NOPE. Shellac will bond to epoxy but not the other way around. So you'll have issues with your pore fill. Question. Why does the order matter? I don't use much shellac anymore but my understanding is that it has great properties of making mechanical bonds to pretty much anything, when wet. The same can't be said for epoxy. Since the shellac is dry (when it goes down as a sealer) the epoxy has problems bonding to it properly. In the reverse situation, the epoxy is dry and the shellac can mechanically bond to it just fine.

Page 1 of 1	All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/