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| Varnish Finish and Bridge Masking http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=16563 |
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| Author: | dmills [ Mon Mar 24, 2008 9:06 pm ] |
| Post subject: | Varnish Finish and Bridge Masking |
I believe the general rule when French Polishing a top is to never mask of the bridge area with blue tape before applying the shellac as the alcohol will dissolve the tape adhesive and contaminate the finish. For those of you who have used Behlen’s varnish as a finish on tops, is it safe to mask off the bridge and fingerboard areas before applying the varnish or would the same cautions be applicable with the varnish finish? |
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| Author: | paul harrell [ Mon Mar 24, 2008 9:50 pm ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
I don't think the tape would hurt the finsih, but I don't tape off the bridge area because it seems more trouble than it is worth. Since you have to sand between every coat of varnish you would have to take the tape off and reposition it each time. Peace, Paul |
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| Author: | Michael Dale Payne [ Tue Mar 25, 2008 8:18 am ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
On new builds I never put the bridge on till after finish. On a refinish job I just work carefully around the bridge. But I don use spirit varnishes much either. I would worry with any raging process that the possibility of the varnishes solvent would draw out some of the tapes adhesive. But I also now a lot work with masking all the time. So the best advice I could give is to set up a test and do it for your self to see if you can make it work. |
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| Author: | dmills [ Tue Mar 25, 2008 8:28 pm ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
Thanks for the responses. Can you remove a varnish finish beneath the bridge footprint with a hot chisel like you can with shellac? I know some people remove the finish in this area with their router but this seems a bit daunting. |
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| Author: | Michael Dale Payne [ Tue Mar 25, 2008 10:00 pm ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
dmills wrote: Thanks for the responses. Can you remove a varnish finish beneath the bridge footprint with a hot chisel like you can with shellac? I know some people remove the finish in this area with their router but this seems a bit daunting. It is actually pretty easy with a small router, but I just use a small cabinet scraper and a micro scrapper made from a utility razor blade, the stiff heavy trapezoidal ones not the thin flexible square ones, they hold a burr longer and and are much easier to control. I first round the edges of the razor and remove any burrs I may have caused on the edges of the ronded corners with a pocket stone. Then pull a burr with a burnishing tool. A hardened steel screwdriver shank will do in a pinch. Locate the bridge and mask off the shape. Add a second masking 1/16" inside the perimeter of the bridge. Now I carefully scrape back to the wood till I just get wood fiber everywhere. Remove the masking, fit and glue up the bridge. perfect finish edge to bridge every time. No matter if I am French polishing or spraying lacquer I do this same process. no heat needed There are some I assume that will mask off the bridge area and finish over the masking and carefully razor scribe the edge of the masked area and remove the masking but I just have been burnt by masking adhesive and never want to go there again so I don't take the chance. |
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| Author: | Barry Daniels [ Wed Mar 26, 2008 4:14 pm ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
Michael, What is the purpose of the second masking tape? Do you route a small ledge on the bottom of the bridge to go over the lip of finish that is left? |
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| Author: | Michael Dale Payne [ Wed Mar 26, 2008 4:44 pm ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
BarryDaniels wrote: Michael, What is the purpose of the second masking tape? Do you route a small ledge on the bottom of the bridge to go over the lip of finish that is left? The first masking defines the outside parameter of the bridge the second defines the limitation of the area to be scraped back. Might help to know that I add a 1/16" chamfer around the bottom of the bridge to allow 1/16" of finish disapearunder the bridge and still have good wood to wood contact. |
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| Author: | Laurent Brondel [ Thu Mar 27, 2008 8:44 am ] |
| Post subject: | Re: Varnish Finish and Bridge Masking |
I use Behlen's Rockhard and do not mask the bridge location. After buffing I locate the bridge, drill the 2 outside E strings through the bridge in the top, bolt the bridge with 3/16" allen bolts & washers (I also use them to clamp the bridge), carefully put blue masking around the bridge and with a brand new x-acto #11 blade cut through the finish maybe .020" inside the tape. I lift/remove the varnish with a curved sharp chisel. No issue so far. |
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