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| Glueing Bridge Over Lacquer Ledge http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=51682 |
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| Author: | Kbore [ Mon Mar 04, 2019 8:22 am ] |
| Post subject: | Glueing Bridge Over Lacquer Ledge |
Bridge is ready to glue onto spruce top of new build. I masked off the location and with tape off, there is a .008- .010 lacquer ledge. I masked to within maybe 1/16" of the edge. Is there anything special you do to account for this ledge? As I understand, the glue ( most any glue) will not fill this gap. Same ledge on the fingerboard extension where it was masked off. How do you guys proceed with gluing over the lacquer ledge? And do you apply glue up the the edge of the bridge, and clean up the squeezout? |
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| Author: | sdsollod [ Mon Mar 04, 2019 10:40 am ] |
| Post subject: | Re: Glueing Bridge Over Lacquer Ledge |
I use a router to remove a slight amount of wood away from the edge. Calipers are used to measure the amount to remove and many test routs are done to get it right. Some folks will use a scrapper... I'm sure others will chime in... |
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| Author: | Barry Daniels [ Mon Mar 04, 2019 11:02 am ] |
| Post subject: | Re: Glueing Bridge Over Lacquer Ledge |
Regarding how do you clean up excess glue. You're kidding right? I use a slightly damp cotton rag. For routing a corresponding ledge on your bridge, make a tiny router table with a Dremel and precision base with a bearing follower to control the width of cut. |
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| Author: | bcombs510 [ Mon Mar 04, 2019 11:13 am ] |
| Post subject: | Re: Glueing Bridge Over Lacquer Ledge |
Kbore wrote: How do you guys proceed with gluing over the lacquer ledge? And do you apply glue up the the edge of the bridge, and clean up the squeezout? I think the question here about glue and squeeze out is if you should apply glue only to the surface in contact with wood or should you also put glue on the "ledge" made by rabbeting / scraping the perimeter of the bridge. Is that correct? I only put it on the footprint of the bridge that is in contact with wood. The squeeze out will happen either way. If you're going to rabbet the perimeter, make sure it is truly deep enough, but don't go too deep or your bridge will appear to be "floating. if that happens, take a little off the bottom footprint of the bridge and test fit until it sits down all around. |
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| Author: | doncaparker [ Mon Mar 04, 2019 11:20 am ] |
| Post subject: | Re: Glueing Bridge Over Lacquer Ledge |
There is lots of content on the OLF about the reasoning behind, and processes toward implementing, the "ledge over finish" way of gluing on a bridge. Others above have touched on the topic; you might want to dig a bit to find more details. I think it also deserves to be said that this is not the only way to glue on a bridge. Some folks (myself included) still clear away all of the finish underneath the bridge footprint. I do it because the bridges I use are already on the small side, and I want to maximize the amount of gluing surface available to help keep the bridge glued on. Removal of the finish all the way is not as pretty if you look up close at the edge of the bridge, but if you do it well, it looks fine. And you are not losing glue surface in the process. |
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| Author: | Clay S. [ Mon Mar 04, 2019 11:39 am ] |
| Post subject: | Re: Glueing Bridge Over Lacquer Ledge |
Another way to approach it is to use a razor blade that has the ends "blunted" (on a stone or with sandpaper) and scrape the ridge of finish down to where it is almost flush with the wood. Assuming you have a 16th inch or less of finish under the edge of the bridge and it is scraped down to be very thin the bridge should glue o.k. |
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| Author: | Hesh [ Mon Mar 04, 2019 8:20 pm ] |
| Post subject: | Re: Glueing Bridge Over Lacquer Ledge |
Regarding the ramifications of the bridge sitting on a ledge of finish, or not.... there are many quality discussions some with pics of the various bridge rabbiting jigs folks here have made are available to you simply by searching "all forum rooms" for "bridge rabbiting jig (without quotes). I just did this and it's a treasure trove of prior threads some going way back. Here's just one of the many threads: https://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=49368&hilit=bridge+rabbiting+jig As someone who usually rabbits bridges and fits them to the "pocket" left by the finish ledge commercially for repair clients it should also always be said that this entire idea of rabbiting the bridge is optional. Many, most guitars were not made this way which although not my first choice most of the time (depends on the finish, condition of the top, etc.) it's certainly not required. You've done a very good job of taking advantage of as much top surface area without clearing finish all the way to the bridge perimeter as you can. Good going. You will see in some of the threads resulting from the search I suggested above pics of well known makers not clearing enough finish. As you've also likely noticed when the bridge has to span that ledge wood to wood contact does not happen at the ledge but a bit inset provided that we clamp well. Anyway lots of ways to do this and lots of justifications for the various methods rabbiting vs. not rabbiting, clearing finish to the perimeter or not, etc here for the reading if you care to dig them up. Take note too of some of the comments regarding clearing finish to the perimeter and why some of us me included Don't like this practice and why. Good questions, good luck to you. |
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