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Just wondering what the latest take is on a tie coat between Zpoxy and nitro. I read here years ago that shellac wasn't a good tie coat and that vinyl sealer was. I have come to believe that vinyl sealer is not great. I think I have read of recent some of you using shellac.

Anyone with lots of experience using shellac for this?

Thanks!

I have contacted "Pacer" regarding nitro compatibility, nitro can and should be applied directly to Zpoxy.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Mr. Vincent:

We had this discussion with the boss over the weekend and I followed up today over lunch via text message. He could not recall whether the notes on the videos now reflect this approach, but I'll make those changes if not.

Here are the salient points of the discussion:

- With McFaddens/Seagraves instrument lacquer, the boss says vinyl sealer for the improvement in overall adhesion and resistance to shock - higher solids and less in the way of flex agents added, and their vinyl sealer is the best of the lot.

- With Mohawk, he feels it's a toss-up between platina shellac, vinyl sealer, and nude - Mohawk's vinyl sealer is not effective at cushioning shock and the lacquer is quite a bit softer than McFaddens with a better plasticiser package, so hangs on a bit better given a naked surface (I was unfamiliar with that term, but is apparently acceptable in what passes for polite company)

- Go with the finish manufacturer's suggestions on tie coat if you don't have some experience with the system. He suggests that he has not used Cardinal, but notes that he thinks it will be closer to McFaddens than Mohawk.

- Make sure the surface of the epoxy is well toothed and no amine blush, etc. remains on the instrument before either sealing or shooting finish coats.

- Accept that some people's chemistry will degrade nitro-to-epoxy bonds, no matter what the tie coat or lack of one. Shellac can help here, but the film thickness required means 2-3 full coats and care in sanding. He notes that this is usually only an issue on the neck, and there is more tolerance for the additional film thickness there than on the body.

I think I got that all - will check and see. Good luck, Mr. Vincent!

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For the times they are a changin'

- Bob Dylan

I have used shellac in between (nitro and epoxy) for various reasons, as well as french polish over Zpoxy ... no issues thus far.

Woodie's boss ... yeah the dreaded amine blush ... good point.

Andy

Reading the email from "Pacer" -- the tech states that the solvents in nitro actually etch the Zpoxy so it forms a chemical rather than mechanical bond --- I believe that is a good thing and what I prefer in a finishing system.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Thanks Ken. I'm going with that........ this time.

Woodie. My dad was Mr. Vincent. I respond to a number of different names. Don't be shy. I'm pretty thick skinned.

I have always used Mohawk. There is a well equipped store in Vancouver. Unfortunately the staff appears to have inhaled a little more of their product than what's good for them. They were the one's that mentioned the cushioning of vinyl sealer. I think for that application, under nitro it's a great product. Also a very good sanding sealer. I am suspect of the adhesion between it and epoxy. My tell tale test is when you sink an awl into the wood for a strap button. How big of a delimitation do you get around the hole. The least I have seen is nitro over shellac. None. The worst I have seen is nitro over vinyl over Zpoxy. Sometimes as much as 1/8" circumference around the awl hole. That and delamb dings on binding corners while at some point between final finish sanding and final user. Those are pretty aggravating.

I agree on the toothing. I'm thinking 220G is maybe the way to go. But that may not help on the corners where it is more likely to occur. It would appear, for whatever reason, time makes this less of an issue.

On necks. I never use any tie coat. I've never had a problem getting enough build up. It's pretty easy to build up a neck with finish even with Mahogany.

I'm going with nitro over Zpoxy for the back and sides. (thanks Ken) It's a first for me. I'll let know when I sink an awl into the butt.

If in fact there is a burn into the Zpoxy like Ken mentioned, that would be a beautiful thing.

Thanks for the well thought response Mr. Stoc...... Woody. Seems like all is becoming well with the Universe.

I spray nitro directly on Zpoxy and have had no problems.
Tom

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A person who has never made a mistake has never made anything!!!

Looking through the archives, it appears as though Mr. Howard Klepper advocated the same thing - nitro directly on epoxy. It does not sound as though there will be any problems with the Mohawk lacquer.

Will convey your thanks, Danny - I've been after him to finish the neck filling video and re-shoot the first three. Not holding my breath, and I'm not sure he'd notice anyway.

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For the times they are a changin'

- Bob Dylan

Haha. Oh he would notice. Would he force you to breath that's another thing. Say hi. He's one of the guys who has made the whole process a lot easier and a lot more entertaining.

What about catalyzed urethane? Seems to me like if nitro sticks, this will too. Anyone have any insight though?

I'm a Mohawk user. I started out using it directly on Zpoxy with no known issues. Then I'm sure there was several discussions hear a few years back about how sealing with shellac was a good thing with a wide variety of finishes. So now I do a light coat of shellac between the epoxy and nitro. Again no known issues either way.

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

The Mohawk vinyl sealer can bind over any epoxy pore fill...to be followed by Mohawk nitro. There are other solutions but I can vouch for that one.

Just make sure the epoxy is FULLY cured and then clean well with solvent prior to the vinyl sealer.

One advantage to using Mohawk nitro over their vinyl is that they claim the topcoat will burn into the vinyl. ....a big deal when it comes to sanding vinyl. You want to avoid that step if you can. Sanding vinyl sucks.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I did a test board with Cardinal. Spraying finish over their vinyl sealer seemed to have a slight advantage over spraying direct on zpoxy. the bond was pretty good both ways.

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Joe Beaver
Maker of Sawdust

Danny, did you sink the awl in yet? delam?