Cracked poly finish

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John Clifford
Posts: 180
Joined: Mon Dec 18, 2017 3:08 pm

Cracked poly finish

Post by John Clifford »

I recently acquired a Parker Fly with a crack in the finish that's been there for several years. I think they used some kind of poly finish. It's more plasticy than lacquer. I'm not worried about how it looks now, but the edges of the finish seem to be getting a little loose and starting to peel back along the crack, and I'm worried about it delaminating or flaking off at some point. I would like to do something to stabilize it, if that can be done without making it look worse. I'm thinking about wicking in some thin CA glue, maybe with a needle injector, but I don't know much about poly finishes. If I get some CA glue on the top, how do I clean it up? Any ideas?
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Fly finish crack.jpg

Joshua Levin-Epstein
Posts: 233
Joined: Sun Jan 08, 2012 7:58 am
Location: Massachusetts

Re: Cracked poly finish

Post by Joshua Levin-Epstein »

Many of the synthetic finishes I've encountered aren't affected by acetone. Find a hidden spot and try both the CA and acetone. You might be able to clean up with the acetone.

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Barry Daniels
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Location: The Woodlands, Texas

Re: Cracked poly finish

Post by Barry Daniels »

Yep, CA and clean with acetone.
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John Clifford
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Joined: Mon Dec 18, 2017 3:08 pm

Re: Cracked poly finish

Post by John Clifford »

Thanks guys. I think I can try it out on an area under the cover plate in back, so that's the plan.

What do you think about clamping? I was thinking I could place 2-3 layers of masking tape along both sides of the crack and lightly clamp a flat caul across those, bridging the crack itself so I don't end up wicking CA under the caul. On the other hand, maybe that's not necessary. The paint still looks pretty level, but I can hear a difference in tone as I tap lightly about 1/4" from the crack, so I know it's coming loose in that area.

David King
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Re: Cracked poly finish

Post by David King »

I wouldn't try to do anything to hold down the edges. Let the CA fill in underneath and leave it alone for 8-12 hours. Use a fine pipette or whip tip and keep paper towel handy to mop up the edges. Wipe across the crack with acetone to clean up any residue on the surface after the glue has set up.

John Clifford
Posts: 180
Joined: Mon Dec 18, 2017 3:08 pm

Re: Cracked poly finish

Post by John Clifford »

Thanks David. I'll probably try it that way.

Chuck Tweedy
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Location: San Diego, CA

Re: Cracked poly finish

Post by Chuck Tweedy »

thin CA will wick under masking tape and cauls. You want NO features for it to crawl under - just the crack.
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John Clifford
Posts: 180
Joined: Mon Dec 18, 2017 3:08 pm

Re: Cracked poly finish

Post by John Clifford »

I’m sure you guys are right. Thanks for the guidance.

John Clifford
Posts: 180
Joined: Mon Dec 18, 2017 3:08 pm

Re: Cracked poly finish

Post by John Clifford »

I followed the excellent advice given above, and it worked out great. No "after" photo, because it looks the same as before, which is exactly what I wanted.

So thanks again. I really appreciate this resource.

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