Repairing guitar finish

ash

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403
I tried to age a nitro finished guitar body using compressed air, but ended up having spider web crackles. Is there any way I could repair/fix this and age it properly?
 

swiveltung

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14,483
aren't those "crackles" what aged nitro is? You mean like crazing right? What were you trying to do looks wise...?
 

ash

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403
Right, the crackles are basically what I want - but they turned way too intense/too many, like spider webs, and do not look very natural.
 

AdmiralB

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3,060
Butyl cellosolve and blush eraser will re-melt the lacquer, but you gotta be damned careful with them. And they'll require further touch-up afterward.
 

K-Line

Vendor
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8,908
If you want big, long, Ron Jeremy checking, freezing with some sort of spray is not the way.
The best way is the razor treatment. Total 100% control. Freezing the body for about 5 days in a deep freeze is also a nice alternative to comp air.
 

swiveltung

Member
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14,483
Butyl cellosolve and blush eraser will re-melt the lacquer, but you gotta be damned careful with them. And they'll require further touch-up afterward.
I was going to say this , but frankly... BE CAREFUL... it takes some expertise for sure... :>)
 

ash

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403
Could you describe a little more how the process with Butyl cellosolve and blush eraser would work?
 

AdmiralB

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3,060
Could you describe a little more how the process with Butyl cellosolve and blush eraser would work?

They're both solvents with slow 'flash' times (meaning they evaporate slowly). Blush eraser often comes in spray cans, although you can also buy it bulk - for mixing with paint, to slow curing time; it's purpose primarily is to allow any moisture trapped in the finish to percolate to the surface before the finish cures.

So essentially you'd spray the offending areas with blush eraser, which would 'melt' the lacquer. It'll re-flow, and when it dries the cracks will be gone. It may take several applications, and you'll have some work to do afterward in terms of sanding and polishing.

Butyl cellosolve works the same way but it generally comes only in bulk (AFAIK). I use it when there's a single crack or defect I want to address, I take a pipette and apply it to the area directly. It has a VERY long evaporation time, not very volatile at all, and it's not quite as aggressive in terms of how quickly it dissolves lacquer.

I think blush eraser is what I'd do here, but a little bit goes a LONG way and I'd practice spraying it on scrap first so you get a feel for how it works. And of course, you don't want it on anything you care about, it's an equal-opportunity solvent.
 

swiveltung

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14,483
AdmiralB nailed it. I bought Cellusolve in a smallish container, long ago though. (pint I think) You need to keep the surface flat while the solvent melts the lacquer... or it will run. I used it last year to repair a 70 YO guitar in one area. I just brushed it on quickly. I bought it over 10 years ago I think. There used to be a video of someone remelting the lacquer on a vintage Martin. By using the Cellusolve they kept the decal intact. I thought it was done by Gruhn, but I haven't been able to find that video in years.
http://www.hvchemical.com/butyl-cel...ueNAy2KH6HPDlqCqOoEC1JDY9HHJwE4EsgaAp_c8P8HAQ
 
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ash

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403
I don't seem to be able to order Blush eraser - US dealers will not ship overseas. Does anybody know if Blush eraser can be bought in Europe?
 

AdmiralB

Member
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3,060
I would think finishing (especially woodworking finishing) supply houses should have it. You might contact Touchstone Tonewoods (touchstonetonewoods.co.uk), they're a luthier supply shop in the UK. They show some finishing stuff; not blush eraser, but I'd bet they would have some ideas as to where it might be found.

It's not just used by musical instrument finishers, though - people doing furniture restoration would use it, the first video I saw on its use was from a furniture refinisher.
 




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