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I'm going to be doing my first Nitro finish maybe next week....and I have a gallon of the Mohawk Classic Instrument Lacquer, and the EZ vinyl sealer that supposedly goes with it in use. But ..in talking to a friend, who's' used it in the past ( he does 100 guitars a year) , he says beware ...he's had trouble in the past, with a bad batch. They had 36 guitars fail in the finish...small cracks of some sort. And the company was hell to deal with.
So my query.....Anyone else here, have problems with this brand? Was that possibly an isolated event, and I'm good to go?
What brand seems to be the most popular here on the forum, anybody know? Any advise / warnings would be greatly appreciated. LMI, has discontinued the Mohawk brand, and switched to Cardinal.

Michael

I use Mohawk piano lacquer and love it. No issues.

I've used Mohawk lacquer with their recommended vinyl sealer on around a half dozen guitars with no problems, even on ebony and rosewood which can be difficult.

Thank you.....it was probably a bad batch, maybe he had....just hoping the product is by and large a good one..

I use Mohawk nitro, but I use shellac as the sealer. I've had no issues this way. I've never used a vinyl sealer before....

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Bit off topic, but was your friend obliged to refinish under warranty?

Yes....absolutely. All of them. Had to take Mohawk to court, got an undersized settlement....lost a bunch a money. I'm told.

I've been using Mohawk instrument lacquer for 10 years with no problems. I generally use it over shellac and have never used their vinyl sealer.

Josh

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Josh House

Canadian Luthier Supply
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Mohawk/Behlens but with Shellac sealer, 21 guitars without problems except I need to be patient waiting for the lacquer to cure before level sanding and buffing. I met Richard Hoover ( Santa Cruse guitars) last month at the Tony McManus guitar summit and after talking to him about what he uses and the benefits and I will switch to Cardinal once my 1 1/2 gallons of Mohawk is used up. Buffing after 10 days to 2 weeks sure beats waiting 4 weeks. I have rushed it a couple times and needed to rebuff after a couple months had passed.

Fred

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Fred Tellier
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Isn't that Cardinal a catalysed lacquer? That why you can level & buff after 10-14 days?

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

This is true... I learned to let Mohawk gas off for at least a few weeks before buffing... much longer than the McFadden's I used to use.

I will leave mohawk to off gas for 4 weeks or longer. It gets good and hard than and sands and buffs like a dream. It would be nice though for a shorter cure time.

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

I used it for many years without a single problem. I decided I didn't like the yellow cast....or should I be nice and say amber so i switch to Cardinal which is water clear.

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Michael F Smith
Goat Rock Ukulele
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What with the adhesion failures I've seen on so many factory guitars, I don't think I'd ever do any lacquer finishing over vinyl sealer. I've never tried spraying shellac, although I understand there are some formulations that work. I still only apply shellac by wiping.

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Frank Ford

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I've had to strip the Cardinal lacquer off the current guitar twice due to adhesion issues over their vinyl sealer.

The first was my fault. After spraying two or three coats of the sealer (Robbie O'Brien's methdod), I let it sit for a few days, then sprayed the nitro without scuffing the sealer. The finish flaked off the back.

Second was on them. I sprayed a coat of the sealer, scuffed the next day per their instruction, and sprayed the lacquer. This time it it flaked off the top.

Third time seems to be the charm. I sprayed the sealer, then two coats of nitro twenty minutes later for good measure. I'll level the final top coats today, but so far it's looking good.

Frank, Were the failures you've seen nitro over vinyl? Although I have used that combo on the last 5 or 8 guitars, I am suspect. The vinyl seems to bond well to the nitro but I'm not sure how well the vinyl bonds to wood. The bond seem to be very fragile especially when it's still fairly fresh, under 2 months.

Thanks,
Danny

My coatings manufacturer Specifically recommends against using vinyl sealer under their nitrocellulose lacquer. They have a sterated nitro sanding sealer for use with the nitro lacquer. The chemists have told me that if a vinyl sealer is used it must be used as a bond coat with the first coat of lacquer wet bonded to it to avoid film failures. The vinyl is recommended for use under the CAB acrylics and some of the pre-cats, although best practice on most of those systems is to use them as a self sealing system..

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Brian

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I've used Mohawk/Behlens nitro on most of the instruments I've built, with no issues. (I can buy it locally and it is manufactured just up the road from here) I do use a coat of vinyl sealer under my first coat of nitro cell usually 30 to 60 mins apart.

When we've seen it on nitrocellulose lacquer finished production guitars it has been obvious that the lacquer has flaked from the sealer coat which was bonded well to the wood. These are instruments from various time periods although I've never seen that effect on ones made before the use of vinyl sealer.

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Frank Ford

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I have been using water based products for my first 35 guitars. KTM-9 for 21 and for the last 14, KTM-SV. I decided to try nitrocellulose for the two I am working on now, so this thread is timely for me. I bought Seagraves lacquer and sealer. The sealer is a vinyl sealer. Is anyone using this? I have been using Z-poxy finishing resin to pore fill and spray the KTM directly over the epoxy. I am assuming I can spray the nitrocellulose directly over the finishing epoxy. Is that a good assumption? And yes, I know what happens when you "assume" - I saw "Silence of the Lambs". Thanks in advance for any help - Mike

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guitarsbygiltzow.com

Just finished some guitars with mohawk nitro over their vinyl sealer. After scraping back down to attach the bridge, there was nothing lacking in the adhesion department, I can assure you of that! I would think if they had a QC issue in the past, they likely would have narrowed it down to lot numbers and got it off the shelves, especially if they paid claims for it. No guarantee that can't happen with another brand too.

Thank you very much for the discussion so far.....I like the Shellac ( used it for years in furniture) idea. So far , I'm not hearing of adhesion issues with the shellac. And, I am not wedded to the vinyl by any means.

What sort of Shellac ( can / flake) you all using to seal? And how, (aside from Frank) are ya'll puttin it on? I have experience so far mixing from the flake (mostly Orange), and hand apply.

And the LB. cut of the Shellac, for sealing under Nitro recommended?

I seal with flake shellac, 1# to 2# cut, sprayed. I do that for all finishes. Not saying that's the way to go, just what I do.

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Steve Smith
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