I'm here to serve, Filippo!
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| French polish question http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=27344 |
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| Author: | WaddyThomson [ Tue May 11, 2010 4:11 pm ] |
| Post subject: | Re: French polish question |
I do my FP with the bridge on, but the way I keep from getting too much build-up around the bridge is to stiff off across the grain where necessary, to keep it down. It has not become a problem. If you are getting too much build up, you may be going too thick with the top finish. I do the same at the neck join. |
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| Author: | Pat Hawley [ Tue May 11, 2010 5:40 pm ] |
| Post subject: | Re: French polish question |
I don't think this method of taping off where the bridge will be is a good one for French polishing. What can happen, and may be what you are seeing, is that the alcohol from the shellac pulls out some of the glue from under the tape and contaminates the finish. If you can't live with what you are seeing, my advice would be to take off the tape, clean up the top and start again. Then when you are ready to install the bridge, clean off the finish in that area. Nice thing about French polish is that starting over is not that difficult. I've done it many times. Pat |
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| Author: | Stuart Gort [ Tue May 11, 2010 6:07 pm ] |
| Post subject: | Re: French polish question |
The presence of rubber adhesive is certainly not helping....which alcohol probably dissolves....as Pat said. Some other time you might get a roll of that green pinstripping tape, which has silicone adhesive, and see if alcohol dissolves that. Maybe that tape will work when this tape doesn't.....but.... ....I'd also guess that due to the thickness of the tape, uncontrollable deposits are going to occur along the edge. The mechanics of FP deposit tiny amounts of shellac in a consistent micro-film. That tape edge has to be messing up the basic idea by forcing material out of the muneca in an uncontrolled way. |
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| Author: | Peter J [ Tue May 11, 2010 7:07 pm ] |
| Post subject: | Re: French polish question |
What you are experiencing is very typical when using tape at the bridge location. I do the same myself and get the same result. It is caused by the muneca hitting the edge of the tape and not being able to amalgamate the french polish at the very edge when it makes contact. Many times the ridges will coincide with the soft grain. As Waddy says, stiff off across the grain right at the edge of the tape to help smooth the finish. Make sure that you are using only alcohol on the muneca when you pull cross grain and do the leveling. Don't be afraid to put some pressure into it. Spend some time applying finish cross grain at the upper and lower edge of the tape to help resolve the issue. As the finish builds along the tape you can also use a small sanding block with some 800 or 1000 paper and olive oil to get it smoothed to your liking. You will undoubtedly pick up a few grains of dirt & dust in the finish as you proceed. Using the stiff off process or the sanding block and oil will help remove them and keep the surface of the FP clean and smooth. |
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| Author: | Jody [ Tue May 11, 2010 8:17 pm ] |
| Post subject: | Re: French polish question |
yes , I had the same problem using the tape as described by the contributors above.I got what appeared to be bubbles rising up from under my top coat while I was waiting for it to harden for use . i removed the tape, very lightly sanded the top back to a smooth surface, traced a pencil line where the bridge would be attached, then went at it with no tape, crossing the pencil line as little as possible and still getting complete coverage. I then used a chisel to scrape off the shellac,( after scoring the pencil line with a knife) glued on the bridge, without a hitch , it has been at least six months and it is holding just fine . Jody |
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| Author: | WaddyThomson [ Tue May 11, 2010 10:12 pm ] |
| Post subject: | Re: French polish question |
I'm here to serve, Filippo!
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| Author: | David LaPlante [ Wed May 12, 2010 9:13 am ] |
| Post subject: | Re: French polish question |
Filippo, I don't think one needs to use tape to begin with. It's much better to have an unimpeded surface to polish, then locate the bridge, mask around and remove the finish before attaching. Cleaner results all around I think. |
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