Did you glue in one of those square truss rods in the Martin neck? I have one off ebay also...
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| How to Salvage http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=19493 |
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| Author: | GHatcher [ Mon Nov 03, 2008 4:59 pm ] |
| Post subject: | How to Salvage |
When I first became interested in building a guitar, I cobbled together a kit from odd pieces on ebay: Martin sides, neck, and top. I filled in what I needed from the normal suppliers and tried to build with minimal tools. I thought I would put one together on the cheap before buying a more expensive kit and more tools. The results were initially OK. It looked OK from 10 feet away and played OK. However, when attaching the neck, I broke the adjustment nut on the truss rod. (There is a recent thread that discusses the difficulty in lining these martin truss rods up to adjust from the soundhole.) After it was strung up the neck began to flex and developed too much relief. I assume I could have fixed this with a working truss rod. Also, the Bridge began to lift. I think I had two issues with the top that caused the bridge to lift. First, I tried to curve the bottom of the braces by hand and I over-did it. Second, when clearing off the finish before gluing the bridge, it appears I needed to clear a little more on one end of the bridge. So these two issues impacted the glue joint. This weekend I removed the bridge and the neck and removed the truss rod and finger board from the neck. If I want to fix this guitar, I believe I need to remove the existing top and make a new one. The current one has way to much arch in the middle which will make gluing a bridge difficult. I now have a bracemaker from Luthier Supplies which I hope will make my braces more consistent. I think I can handle removing the top, basically if I route as if I were cutting a purfling ledge the depth of the top, I should be OK - Correct? With the neck, should I assume that with a new truss rod the current Neck and Fingerboard should work. I will need to scrape off all the old glue, but otherwise, should these be fine to use. What do you think, try to reuse the neck and fingerboard Also, I originally had the truss rod installed so that it ended about 1/2 way between the nut and the first fret. Should I have taken it all the way to the nut? Not sure why I did it this way? Looking at the LMI Kit I am currently trying to complete, I have that one going pretty much to the nut. Sorry for the long post. I guess what I am looking for is: 1. Is it probably best to remove the top? 2. Is it normal for stringing up a guitar to add significant bowing? The martin style truss rod has a stout steel tube around it that I thought / hoped would keep things straight. Is this concern for a weak Neck or should I just get a new truss rod and give it a try? 3. Should I assume the bridge and fingerboard should be OK to use again? I appreciate any comments. Greg |
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| Author: | Colin S [ Mon Nov 03, 2008 5:24 pm ] |
| Post subject: | Re: How to Salvage |
Let me just deal witrh the top/bridge problem. I don't think you have to remove the top, from what you say, all you need to do is fit the bottom of the bridge to the arch of the top, then the glue joint should be fine. To do this, and you need to do it on all guitars that you make in the future, is to put the same arch on the bridge botton as on the top of the guitar. The easy way of doing this is to put a sheet of sandpaper, 120 or so face up on the guiter top in the bridge position and work the bridge over this until it has the correct shape on the base. Check this by pencil cross hatching the bridge bottom and work on the sandpaper until all of the pencil marks have gone, then repeat with 240 grit to clean up the marks. Clean up the finish on the top to the bridge outline and you should be ready to reglue the bridge. Colin |
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| Author: | GHatcher [ Mon Nov 03, 2008 5:40 pm ] |
| Post subject: | Re: How to Salvage |
Colin: Thanks for the response. I understand what you are saying. I tried the process you discussed, but obviously did not do a good job. With the guitar I am working on now (not the one we are discussing), I definitely did the pencil mark test and it helped me to identify that the bridge was not flat to begin with. I had to work through existing unevenness before I could get a good fit. Maybe that will fix this bridge as well. Thanks |
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| Author: | Hugh [ Tue Nov 04, 2008 12:50 pm ] |
| Post subject: | Re: How to Salvage |
Maybe everyone knows this, but that system of sanding only works if you sand in one direction. On the other hand, maybe it's my unsteady hand that makes me think that way. |
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| Author: | GHatcher [ Tue Nov 04, 2008 8:24 pm ] |
| Post subject: | Re: How to Salvage |
Hugh: I assume that I can send back and forth if I am going with the grain. Are you saying I should only go forward?? Thanks for the reply Greg |
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| Author: | Hugh [ Wed Nov 05, 2008 1:24 am ] |
| Post subject: | Re: How to Salvage |
You put sandpaper on the top and pull the bridge across the sandpaper and the bridge takes the shape of the top under the sand paper. When I go both directions I tend to rock the bridge slightly and round the bottom of the bridge. Short strokes in one direction give me better results. You will probably go against the bridge's grain. Some guys with better control might not think just one direction is a consideration. |
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| Author: | Frei [ Wed Nov 05, 2008 1:29 am ] |
| Post subject: | Re: How to Salvage |
Did you glue in one of those square truss rods in the Martin neck? I have one off ebay also...
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| Author: | Ken Franklin [ Wed Nov 05, 2008 10:07 am ] |
| Post subject: | Re: How to Salvage |
I have made a block with a slightly smaller radius. I attach sandpaper to it and clamp it in my vise. Then I run my bridge blank over it before I shape the bridge. It would still work with a finished bridge but it's harder to hold. The extra radius has helped with my fit at the edges. I also take short strokes which leads to a better fit. |
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| Author: | TonyKarol [ Wed Nov 05, 2008 12:36 pm ] |
| Post subject: | Re: How to Salvage |
I do what Ken does - I made the sanding block an 18 ft radius, to fit the 28 of the top. Across a 6 inch span, the delta between the curves is very small, and that helps get the bridge wings sitting tight. Another trick I use is to leave the bridge a little long while fitting the curve (obvioulsy you cut it longer in the rough). The ends/corners of the wings always seem to take on a little curve/bevel, and the best way I found to get rid of them is simply sand the bridge shorter by about 1/16 at each end !!! As a matter of fact, I just did that yeterday prior to guing one on. Tight fit all round. |
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| Author: | GHatcher [ Wed Nov 05, 2008 5:10 pm ] |
| Post subject: | Re: How to Salvage |
Tony and Ken: thanks for the replies Frei: I did use one of the square Martin truss rods from LMI. As I disassembled the neck, I was wondering why the truss rod ended between the first fret and nut rather than at the nut. Looking closer, the channel ramped up towards the nut and was not deep enough to install the truss rod closer to the nut. I had originally covered this ramp with a piece of wood for filler. I chiseled out the filler and leveled the ramp so that the truss rod should fit in right at the nut. I am suspecting the location of the truss rod or in other words this gap that did not have the truss rod led to the exaggerated bend in the neck. I have a new truss rod on order - again the Martin style since I know that it fits the slot. Hopefully, the neck will be more successful this time. And the bridge will be better installed as well. This guitar will never be a beauty, but I hope it will be playable. |
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| Author: | Alan [ Wed Nov 05, 2008 7:03 pm ] |
| Post subject: | Re: How to Salvage |
I am only working on my fourth, but have used the Martin style truss rod made by Gotoh on all of them. Sounds like you had it installed correctly (between the nut and first fret). From what I understand, the end of the rod should be approximately one inch from the nut. |
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| Author: | GHatcher [ Mon Nov 17, 2008 5:48 pm ] |
| Post subject: | Re: How to Salvage |
I am close to putting this one back together. I only need to finish some cleanup on the fingerboard and then epoxy it to the neck. A new question: To make the fingerboard look a little better, I trimmed the sides and added ebony bindings. I know I do not finish the playing surface of the fingerboard, but should I add some finish to the edges? This is going back on a neck that is already finished, so otherwise, no need for any finishing work. Thanks |
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| Author: | David R White [ Wed Nov 19, 2008 2:46 pm ] |
| Post subject: | Re: How to Salvage |
I finish the edges of the finberboard binding and I think that's normal. |
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