Moisture IN Poly Finish

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Moisture IN Poly Finish

Postby Dave Gentner » Tue Mar 08, 2016 3:24 pm

I'm resetting the neck on an old Yamaha F-110. After steaming out the neck there are milky splotches on the top of the guitar. I assume this is moisture that has penetrated the finish. If this was a nitro finish I would lightly wipe it with denatured alcohol, but this finish is poly something. The alcohol does nothing. any ideas on how to remove the milkiness?
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Re: Moisture IN Poly Finish

Postby Ryan Mazzocco » Tue Mar 08, 2016 7:24 pm

be careful. If you steamed too much it might actually be the poly separating from the wood. I've done that on a cheap model before. can we see a picture?
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Re: Moisture IN Poly Finish

Postby Dave Gentner » Tue Mar 08, 2016 7:55 pm

Don't think its separating. Tried a hair drier to no avail.
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Re: Moisture IN Poly Finish

Postby Barry Daniels » Tue Mar 08, 2016 10:17 pm

Sometimes polishing the area with an electric buffer and polishing compound will heat the finish and pull the moisture out. Certainly couldn't hurt as long as you don't overdo it.
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Re: Moisture IN Poly Finish

Postby Dave Gentner » Tue Mar 08, 2016 10:57 pm

Buffing was the first thing I tried.
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Re: Moisture IN Poly Finish

Postby Mark Swanson » Wed Mar 09, 2016 9:28 am

You don't have an F-110, you have a red label FG-110, which is very different, and a pretty good guitar, from the early 70's.
This one has a lacquer finish and alcohol will mess it up big time so don't use it.
This will wetsand off with 600 grit paper, then buff off. It's on the surface, happens to me too.
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Re: Moisture IN Poly Finish

Postby Dave Gentner » Wed Mar 09, 2016 4:58 pm

You're correct Mark, it is a red label FG-110, but the finish is not lacquer. It's poly. Acetone doesn't phase it. I work with nitro cellulose lacquer everyday. It's the only thing I shoot on my guitars. So I'm familiar with the product. I did manage to get rid of the milkiness however, basically with heat, using a combination of a hair dryer and much buffing.
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Re: Moisture IN Poly Finish

Postby Mark Swanson » Wed Mar 09, 2016 6:19 pm

Well, I don't know for sure what they used then, but back when they were made in the 70's they didn't have much to choose from. The finish is very thin, not like poly you see these days.
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Re: Moisture IN Poly Finish

Postby Dave Gentner » Wed Mar 09, 2016 8:17 pm

I stand corrected. After reexamining the finish I believe it is lacquer. I thought I had touched it with acetone, but realized I hadn't. I was basing my assumption on the way it reacted to the alcohol. I lightly touched an inconspicuous spot with acetone and it softened. So my apologies Mark.
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Re: Moisture IN Poly Finish

Postby David King » Wed Mar 09, 2016 9:16 pm

I was a little surprised the other day to discover how susceptible lacquer can be to alcohol. I was cleaning up a 70s Fender bass under the pick guard and the alcohol immediately melted the lacquer as if it were shellac.
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Re: Moisture IN Poly Finish

Postby Barry Daniels » Thu Mar 10, 2016 10:33 am

Alcohol is sometimes one of the components in lacquer thinner.
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