Trouble with polyurethane refinish

hitrome

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I'm doing a partial refinish on an old Teisco neck and I'm having some trouble with applying polyurethane. I am using an oil based polyurethane clear gloss finish and I'm not getting the results I was hoping for. I've sanded back and reapplied several times with a foam brush and the finish quality is still poor, although better with each added coat. I'm wondering what I can do to make this look like it's supposed to? Here are some pictures of what's going on:


I'm just not sure on what to do next. I feel like I'm spinning my gears without much improvement. I'm also doing a similar refinish on an old B.C. Rich Warlock which is also giving me problems. I can't seem to match the new finish with the old. Any advice? Is there any reason for me to be hopeful with this? Thanks!
 

Skyjerk

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My recent experience with refinishing leads me to believe that once the finish is sufficiently old, or you just want a different look, you should burn that old guitar to ash, and buy a new one.

Attempting to strip the old finish will lead one to removing ones hair, walk8ng around kicking things and swearing, making ungodly messes, and all this before you’ve even gotten 2 sq in of the old finish off.

Mad props to people that do this for a living, but frankly you must be some kind of high level masochists ;-)
 

B. Howard

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Mad props to people that do this for a living, but frankly you must be some kind of high level masochists ;-)
Thanks, I think......


As to the OP...... hardware store poly like min-wax will never blend into the original finish without witness lines etc.
 

hitrome

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Thanks, I think......


As to the OP...... hardware store poly like min-wax will never blend into the original finish without witness lines etc.
What would? Could I spray lacquer over the top and sand that back?
 

lpfan1980

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Thanks, I think......


As to the OP...... hardware store poly like min-wax will never blend into the original finish without witness lines etc.
Heeyy man Poly isnt Groovy..al the hip guitarists love N itro duuude it lets the wood breethe mannn and it eats yer brainnscells poly is fer square nerrrds.-kidding good luck.:thumb:
 

B. Howard

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What would? Could I spray lacquer over the top and sand that back?
You can, but without removing the poly you put down it will not melt together like it should and you will still have witness lines. Unless you bury it under a heavy layer in which case it will crack and flake. Modern nitro isn't the same either..... it is much softer than what was used back then and this creates issues when do repair work. I usually prep and then soften the old lacquer with some retarder to ensure a good chemical bond otherwise the new stuff isn't strong enough to burn in on it's own to old dried out nitro.
 

Freddy G

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Heeyy man Poly isnt Groovy..al the hip guitarists love N itro duuude it lets the wood breethe mannn and it eats yer brainnscells poly is fer square nerrrds.-kidding good luck.:thumb:
What is your point? Brian made a factual statement.
 

fretman_2

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Well...one of the issues looks like witness lines. Oil based poly is different than nitro lacquer. Nitro melts into previous layers and oil based poly does not. If you sand through a poly layer into a previous layer and your surface isn't level, you may get witness lines.

It appears that a good bit of the grain was showing through as well. What poly did you use...wipe on poly or the poly that's typically applied to floors and is much thicker? You can try building up your layers with the thinner wipe on poly and you may have better luck with witness lines. But don't sand after you apply. Just scuff it up with some steel wool so the next layer will stick to the previous layer. Also, if I apply a poly finish, I'll use satin which tends to minimize some of the issues using poly.

Poly can be a great finish if you work within its limitations.
 




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