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| Hey finishing gurues..advice please http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=3943 |
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| Author: | John Kinnaird [ Wed Nov 30, 2005 11:00 am ] |
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I built a honduras rosewood guitar that has a catalyzed polyester finish. The finish looks great except in a small area near where the neck attaches to the body. There is a small area, about the size of a half dollar, where the finish is delaminating from the wood. The guitar came back for a finish touch up, naturally. I have asked the finisher for advice on patches, and he recommended CA glue. CA glue does wick up nicely into the edges of the unattached finish and it seems to hold nicely. (As my brother once so eloquently put it, CA will glue butter to air) BUT, the problem comes during the buffing stage. The areas where there is only CA glue polish up very nicely. (CA really does take a good shine) However, CA is softer than catalyzed polyester and by the time the polyester has a shine the CA has been eroded down enough to show not only a witness line, but also a visible ledge. Due to the irregular shape of the patch I can't buff accurately enough to only buff the CA or the Polyester. Does anybody have any ideas for this repair job, short of respraying the entire side of the guitar. Aaaarrrrgggghhhhh. These little problems can be sooo time consuming. |
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| Author: | Bobc [ Wed Nov 30, 2005 11:24 am ] |
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John how about covering up the CA area with masking tape as best you can and buff the surounding polyester going right over the tape until the poly is close then remove the masked area to finish up? Just a thought. For sure these little repairs can drive a person to drink. 
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| Author: | John Kinnaird [ Wed Nov 30, 2005 11:33 am ] |
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[QUOTE=Bobc] For sure these little repairs can drive a person to drink. [/QUOTE]
Bob. What an excellent idea. I like the tape part too. I may try that. |
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| Author: | Bobc [ Wed Nov 30, 2005 12:43 pm ] |
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John I thought you might like that idea. Try the drinking part to-nite and the tape tommorow. 
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| Author: | Pwoolson [ Wed Nov 30, 2005 1:22 pm ] |
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John, did Addam do that finish? If not, you might contact him as he's got a fix for just about everything. Can Poly not be drop filled? You'll possibably see a witness line but at least the material is the same so it should remain level. Just a thought. |
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| Author: | Tim McKnight [ Wed Nov 30, 2005 2:17 pm ] |
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Poly or Urethane Lacquer does not drop fill as it needs a rough surface beneath for the new finish to mechanicaly bond to. It will not burn in unless the finish is only a few hours old. I have dropped filled with CA and also done the CA repairs for delaminating. Seems like the CA makes the drop fill shrink a bit and I also fight withwitness lines. I was told by McFaddens that it is best to just sand and re-shoot an entire panel and make the break at an edge, neck joint or tail wedge. These seem to be the best ways that I have found to repair catalyzed finishes. |
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| Author: | Howard Klepper [ Wed Nov 30, 2005 3:05 pm ] |
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Doesn't the finisher guarantee his work? Why are you making this your problem? |
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| Author: | Mario [ Wed Nov 30, 2005 3:18 pm ] |
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As Tim says, the only repair for polyester is to re-shoot the entire plate. On an older instrument with damage, we can use CA and other tricks, but on a new one? Or even a year old one? Re-do the entire panel. In fact, it takes less time to do this repair than any other finish repair. In 24 hours, you can have it sanded down, re-shot, buffed and in the owner's hands again. In that respect, it is more easily repaired than even nitro. we just need to get our head wrapped around the idea of re-doing 2 square feet of surface to repair a 1/2 square inch of damage or flaw. And yet another reason to do your own finishing; problem occurs, you fix the problem.... Oh, and polyester is really fussy about what it goes over, and it does not like rosewoods! trust me <sigh> I';ve had a nightmare this year, but have finally got a hold of it all. The sealer, having enough of it on, having it well cured, and having it mixed right is imperative. Don't get it right, and it delaminates... |
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| Author: | Ken Franklin [ Wed Nov 30, 2005 6:02 pm ] |
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I've had some luck with letting the CA sit about a week before leveling and buffing. It seems to get a little harder. Accelerator makes the CA harder, too. Rick Turner I'm sure has some advice about this problem. |
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| Author: | Dave White [ Wed Nov 30, 2005 9:50 pm ] |
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John, From some of the things I've read about poly finishes, they were meant to be the "dog's b******s" of finishes (but then I noticed you said it was "cat" - alysed). It just goes to prove the saying "You're never finished with a finish!"
Well that's me finished. |
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| Author: | John Kinnaird [ Wed Nov 30, 2005 10:59 pm ] |
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Hesh I just take a micro dropper and flood the CA into a small puddle, spreading it out more or less evenly with the tip of the dropper. Be careful when wiping CA on (or off) with a rag. Once I did that, had the CA wick into the rag onto my underlying finger. A puff of smoke rose from the rapidly catalyzing, HOT, CA and that rag was glued to my finger with a blister forming underneath from the heat liberated. Very stressful. I trimmed the rag and wore the remaining patch as a sort of protector until the pain subsided, a day or so later, and then sanded it off. |
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| Author: | Robbie O'Brien [ Thu Dec 01, 2005 1:32 am ] |
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On the Taylor repair I recently posted picks of here, I sprayed over the factory finish with a cat urethane. The client didn't want to pay for a complete refinish job so I just taped off a large area around the repair. After removing the tape of course I had large spray lines that became witness lines as I sanded and buffed to a high gloss. The secret to hiding these is a quick coat of French Polish in this area. They disappear. However, to really do it right you need to do a whole panel of the guitar. I use cat urethane over everything with no adhesion problems. |
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| Author: | Howard Klepper [ Thu Dec 01, 2005 5:56 am ] |
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[QUOTE=Robbie O'Brien] I use cat urethane over everything with no adhesion problems. [/QUOTE] Give it some time. |
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| Author: | Addam Stark [ Thu Dec 01, 2005 8:58 am ] |
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You bet. If it is a problem with my work in any way I always fix it for free! Most of the time I will repair thing that are not a problem that comes from my work for free, dents from setup, or any or the many things that can happen when a guitar is setup. |
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| Author: | Mario [ Thu Dec 01, 2005 1:06 pm ] |
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Addam, ever given some thought to moving to Northern Ontario? Canada? <bg> Gads, I'd love to have you as a neighbor.... |
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| Author: | Steve Kinnaird [ Thu Dec 01, 2005 1:37 pm ] |
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Or East Texas? Same sentiment. Steve |
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| Author: | Don A [ Thu Dec 01, 2005 1:39 pm ] |
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We could sure use a branch here on the east coast, preferably Virginia! |
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| Author: | John Kinnaird [ Fri Dec 02, 2005 1:30 am ] |
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Addam is the best and I find it cost effective to have him do the work. It only costs me $40 to ship a guitar from Georgia to California, (and $40 back) and I just factor that into the cost of doing business. I have made a small plywood box (actually have 3 of them now) lined with foam rubber and covered with cardboard to make the postoffice happy, and I just ship out the bodies and in several weeks time they come back to me with a beautiful finish. I decided about a year ago that I would not finish a guitar for what Addam charges me to do it, so I have been relieved of that unpleasant, unhealthy task, and now I can concentrate on building. Plus he does better work than I do so there is that increased quality factor that works to my advantage. Addam was eager to fix that polyester problem, I am just trying to work it out myself for some strange reason which I am beginning to find undefensable. John |
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| Author: | Jimmy Caldwell [ Fri Dec 02, 2005 6:57 am ] |
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Steve, I've found someone to do my finish work who does an excellent job. He's in Austin, but at least that's in the right state. He worked for Collings for 5 years and currently does all the finish work for Tom Ellis mandolins. You know what kind of reputation Collings has for finish quality and Tom builds world-class mando's, so the guy has quite a pedigree. He'll do nitro or hand rubbed varnish. He had two of Tom's mandolins in his shop the day I went and they were spectacular. If you're interested, PM me and I'll give you his name and number. |
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| Author: | Addam Stark [ Fri Dec 02, 2005 10:55 am ] |
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Hey that's Josh, he and I have talked many times, very nice guy. You guys can PM me for his # also and for any other finish problems or ideas. |
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