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I used Enduro Var over a Z-Poxy pore fill on a recent build and it seemed to go OK.

I'm just starting another finishing project and decided to use their sanding sealer as a 'sanding sealer' with Enduro Var as a top coat.

I decided to visit their site just to see what I could learn and apparently Enduro Var should not be used as a top coat over their sanding sealer nor should it be used as a top coat over anything but "WATER-BASED STAINS, DYES AND RAW WOOD."

"General Finishes Enduro-Var is an oil-modified water-based topcoat and ONLY ADHERES WELL OVER WATER-BASED STAINS, DYES AND RAW WOOD. It will adhere over an oil-based stain ONLY IF the stain is completely dry (minimum 4 days dry time). Use Enduro-Var over any other surfaces at your own risk.

https://generalfinishes.com/wood-finish ... d-urethane

https://generalfinishes.com/wood-finish ... ing-sealer

"Sanding Sealer is not recommended as a final finish because it is not as durable as a topcoat. Seal Sanding Sealer with any General Finishes water-based topcoat, EXCEPT General Finishes Enduro-Var, for improved water and chemical resistance."

Just a bit confused and wondered if anyone can shed any light on these specs and real world application, even by some pretty well known luthiers...

Thanks

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Thank You and Best To All

"Enduro-Var wood finish is a self-crosslinking, oil-modified, water-based polyurethane "

All I need to know in one sentence.... Oil and water do not mix, basic chemistry so an oil modified water base is feat of chemistry in and of itself. It must be constructed entirely of Glycols for the "water base" part to make it compatible with any type oil..... Not surprised such a thing would have compatibility issues. Especially with a sealer because sealers as you note are not finishes but bridges between substrate and finish and are generally "softer'" or more open resin lattices so a glycol could really get into the film and cause havoc.

I think however that due to the nature of monomers like epoxy that adhesion to that as a substrate shouldn't' be an issue with proper prep work.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Thanks and an interesting analysis Brian. Cannot argue the science, just perhaps a bit surprised that their finishes would not be compatible. I can easily sand off the sealer and proceed and it sounds like that's the best course and schedule to follow.

Perhaps instead of the sealer that I used to 'seal' the top from CA stain etc. I'll simply use the Enduro Var over the raw wood and over the prepped Z-Poxy pore fill.

Pretty sure I'm not the only one using Enduro Var and was wondering what else might be important in its application....and thank you again for the timely information.

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Thank You and Best To All

I'm not certain any nitrocellulose lacquer manufacturer suggests epoxy as an undercoat/filler, and I suspect most poly/shellac/other WB systems have some caveat similar to Mohawk's vinyl sealer language:



That said, Mr. John Greven and others have a track record on Enduro-var over epoxy and it appears to be a reliable system. Our own work suggests that the finish is very reluctant to let go of either wood or epoxy, and what testing we've done (tape tests on epoxy/Enduro-Var coupons) showed excellent adhesion.

Re: sealer compatibility...having done both applications over raw wood and epoxy filler , we see no real advantage to an added tie-coat, given how tenaciously E-V hangs on to both surfaces. If using E-V as both filler and sealer, three coats applied within the timeframe for 'no sand' recoat seems to be enough to fill mahogany sufficient to sand back and start the topcoats.

You might search on MIMF, Mandolin Cafe, and some of the other build sites - lots of good threads on E-V and Pro Topcoat, with some discussion of the stated limitations versus actual practice. Even 10 years ago, I'd have agreed with the frequently posted admonition to follow the manufacturer's advice to the letter, but recently, I'm seeing more and more 'CYA' language in user directions that appear to have passed through the Legal Department a few times too many, and far less actual 'what works' info in the PDS.

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For the times they are a changin'

- Bob Dylan

Thanks Willard, good advice me thinks. I had not used the sanding sealer previously and that note raised a couple hackles but it's easy to simply use straight Enduro Var on the top wood.

Curious, did you mean to write Mr John Greven?

Thanks again

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Thank You and Best To All

Spell check is the devil...

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For the times they are a changin'

- Bob Dylan