Nitro lifting

redking

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I have had a few instances of nitro lifting on a couple of my Warmoth builds - looks like I tightened the tuners too much causing this to happen. I used Behlen stringed instrument lacquer (rattle can) on these originally - is there a solvent that I could use to spot repair these little spots and get them to re-melt back down the the wood's surface? (Maybe dab it with a q-tip?)

1620943525834.png
 

ARandall

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You need to get under the edge. So use a countersink bit or reamer on the tuner hole to break the edge and wick in some very thinned nitro with a pipette.
 

redking

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You need to get under the edge. So use a countersink bit or reamer on the tuner hole to break the edge and wick in some very thinned nitro with a pipette.
Thanks for the reply! Since I use rattlecan nitro, do you think I could get away with spraying some into a little cup and sucking that up with a pipette - or do you think I should buy some thinner and thin it even more? It was my understanding that rattlecan nitro is already quite thinned out, but I could be wrong. Thanks!
 

redking

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So now that I have done a series of truss rod adjustments on the three Warmoth guitars that I assembled and finished last summer, I have noticed these little nitro lifting spots on the face of the headstock on all of them where an edge has gotten bumped or nicked (ie. as shown above, or around the truss rod access hole). What did I do wrong in my finishing schedule? The finish is obviously not sticking well enough so that the slightest jar is causing it to lift. I did a light sealer coat of flake shellac prior to spraying aerosol Mohawk Stringed instrument lacquer.
- Incorrect sealer coat? (light coat of flake shellac)
- Poor quality lacquer product? (Mohawk Stringed Instrument Lacquer)
- Failure to let it cure long enough? (by memory, let them hang 2 weeks before handling them)
- too thin a finish? (by memory, did 15 passes or so with an aerosol can (just enough to bury the decal))
- all of the above? (probably!)

thanks (I hate finishing - I have zero patience for it, but would like to be able to do at least a "decent" job of it. :confused:
 

Freddy G

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Only thing you did different than my schedule is shellac. I never use shellac.
 

Freddy G

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Ah.....Warmoth? From warmoth's website:

All our necks are dipped in an oil based penetrating sealer

That's my guess. Maybe the shellac didn't like it. Did you sand first before applying shellac? If not that could (likely) be the issue.
 

redking

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Ah.....Warmoth? From warmoth's website:

All our necks are dipped in an oil based penetrating sealer

That's my guess. Maybe the shellac didn't like it. Did you sand first before applying shellac? If not that could (likely) be the issue.
Thanks for your reply!
Oh man - I thought I was doing something good by adding shellac to the schedule - guess not! My thought being "everything sticks to shellac and shellac sticks to everything" :doh:
Now that I think about it, I believe I only wiped shellac on the face of the headstock (so as not to apply the decal to bare wood) and I have had zero issues with the nitro lifting on the sides and back of the neck so far. Hard lesson learned - maybe when I am bored next summer I will re-do them. Since the shellac penetrates the wood, what is the best way to rectify the situation - will simply sanding away the old finish and a small amount of surface wood do the trick?
 

LtDave32

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Yep. Bare wood and a do-over.

On shellac:

The old adage is pretty much true, "everything sticks to shellac, and shellac sticks to everything", but it doesn't get brittle-hard in my experience.

I used to use it as a sealer, and in the old days, most guitar makers did too. Now I find that lacquer-based vinyl sanding sealer does a much better job in many ways, so it's my go-to every time for a sealer. It also provides another service as a build coat(s) before lacquer. With the sanding sealer, they say "20 minutes" and you can sand. Nah. It is still gummy. Better results are had by waiting several hours before sanding, or even a day. Then you get that fine, white powder sanding residue you were looking for.

You are using very good-quality rattle can lacquer, so it should harden after a few weeks. IF you used the cheap shit at home stores, you can guarantee it won't harden for months, if not ever.

So give it time to harden up, and don't wrench down hard on the tuner bushings.
 

moreles

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Great info from Freddy and Lt Dave. This will save me some trouble in the future for sure. "Oil based penetrating sealer." I'll be darned. That never would have occurred to me.
 


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