Replacing a guitar Soundboard

[Phil Bonneau]

Hi,

While applying the second coat of tru-oil to my guitar, I made a wrong move and my guitar had a rather violent meeting with the garage floor. The soundboard was badly damaged. and I am about 99.99999999% sure it needs to be replaced 😁. I have all the pieces that broke off, but it is pretty trashed around the bridge where all the string tension will be. 

I can get the neck off, and I can remove the bridge, 

How do I get the soundboard off without damaging the binding channels?

How do I size the top so it can take the same binding purfling arrangement as is presently there?

Thanks, 

Phil Bonneau

[Joe Shuter]

Phil, really sorry about your accident.I don't have any suggestions but I am sure someone on the forum will have some positive advice. Scooter

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[David Payne]

Phil,

If I were doing this work I would remove the frets and use heat to soften the glue under the fret board and carefully remove the fret board. Then I would setup the binding cutter fixture to route out the old binding. After the binding is removed I would use heat again to slowly work the top loose from the kerfing, heel and tail piece.  Once the top is off I would build the new top an carefuly align it to the original kerfing. I would cut the outline of the new top to allow some precise overhang so the top could be routed again in the binding cutter after it is glued in place. Then I would rebind the guitar. The old bridge could be removed and the location marked on the new top. Then I would refinish the new top and replace the bridge.

It's a big job but with care should be doable. 

Nikko

Constantine Guitars

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[Phil Bonneau]

Thanks Nikko, That is a great process. I really didn't get too upset when it happened. I just stood there stunned and thought. What am I supposed to learn from this, If I carry out this process, and I plan to,  I will be experienced in repairing this problem.

Thanks,

Phil Bonneau

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[Barry Oren]

I second Nikko’s approach.

In His Name -

Barry 

[Barry Oren]

Another thought for you. If you can find a trashed guitar, it would be a great idea to practice on removing its top. I find such things at yard sales, Goodwill, etc.

In His Name -

Barry 

On Jun 25, 2024, at 1:01 AM, Phil Bonneau <pianb...@gmail.com> wrote:

[David Payne]

Barry,

Great idea!

Phil,

I've been starring at my rosewood classical for a month because something fell on it's top while I was moving and really messed up the guitar (mostly cosmetic). I have been thinking of replacing the top ever since. This will be good experience for both of us. I have been searching for a new Engleman top set but it's hard to find a nice AAAA or AAA set.

Nikko

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[Paul McEvoy]

Is there a reason you don't just rebind the top?  If it were a restoration I could see saving the binding but if you bound it it seems a lot easier to rebind it. 

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[David Payne]

Hopefully Phil can get or has matching binding because I don't see a way to save the binding on a re-top.

Nikko

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[JohnParchem]

John Greven used to have a tutorial on a website. I am not sure he maintains the website any more. It is way to much to really describe in a post but it is possible. But I will give it a go. Unless the purfling and bindings are not replaceable but new ones in! I did it of a older guitar where I could not replace the binding and I did not want to refinish the entire guitar. 

Before any routing get the body in a mold with the ability to hold its shape once the old top is cut out. The body will want to deform. 

First trick is to get a somewhat closely profiled new top with the rosette and sound hole cut but not yet thicknessed. Double stick tape a bunch of top 2-3 mm scraps 1" x 1" all over the old top. Then using the sound hole for alignment double stick tape the new top on what are now spacers on the old top. With this in place, setup up a binding machine router to the inside depth (into the new top) of your purfling line. Just deep enough to cut the new top but above the old top. If a bearing was used, use the same one and with a few passes route the new top to fit just inside the purfling line. If not using a bearing sneak up and route the new top using the binding machine to just inside the purfling line. Now you have a perfectly profiled top; carefully remove from the double stick tape (that is why not to thickness until after removing the new top from the tape)

The next stop needs a new or modified router jig that indexes on the rims but can reach over the good purflings and route out (using a 1/4" end mill or close) the old top just to the purfling with  depth of the cut to the linings. (sneak up both dimensions) I get very close to the purfling and finish by hand with razor blades and sand paper. After routing The top is still probably attached with the braces so cut them either with a deeper route away from the bindings or by hand. Careful as the braces are under the purfling lines. Clean up and repair any damaged linings without goofing up the purflings which are sitting on the linings. 

Now the top will fit inside the old purfling line.  Brace the new top. Carefully cut rebates for the attached braces again without goofing up the purflings. Finesse all to fit then glue on the top. The body wants to deform after the old top is removed, but the new top was cut before that happened so you can deform the body to make the new top fit. 

 Good luck. 

[David Payne]

Phil,

Some links:

I don't like how Burnham guitars split the fretboard in the first link, not sure why he didn't just remove the fretboard but it's an interesting process he describes.

https://www.wilsonburnhamguitars.net/2020/12/replacing-classical-guitar-top-part-one.html?m=1

Obrien video:

https://youtu.be/nTluvZYG8po?si=5isHYHQmpQ3WRKd2

Nikko

https://groups.google.com/d/msgid/obrien-forum/6add40af-21e0-419e-abcc-d36ba7bffc5dn%40googlegroups.com

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[Neil Crump]

Here's a '74 Ovation I'm planning to retop. Hoping to leave bindings undisturbed and reuse the original bridge/braces...time will tell!

Neil

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[robnewell54]

Hi Phil

I feel for you! I have actually replaced the soundboard and preserved the bondings of a much loved guitar that got cracked well beyond repair inflight. It is painstaking work, but not actually as difficult as it might appear. It was hand built by Nigel Thornbory of Hampshire UK and has beautiful bindings, including superb mitres which I knew would be beyond my skills at the time  to replace, so I couldn't just take the top off using heat and palette knife. This is what I did instead.

1 Routed out the soundboard to about an inch away from the edge, then cut through the braces to complete removal of the general top area (japanese pull saw, but most anything would be fine - you have to accept you will be replacing the braces as well as the top).

2 Used a heatgun (low heat) and a palette knife and chisel to remove the rest of the sound board in small pieces up to and including the purfling (the heat is there to warm the glue and help ensure you don't chip off bits of the kefted lining or the binding by mistake (more skilled people than me might not need the heat - if I was doing it again I would still use the heat; you only get one go). In my case, the guitar needed a neck reset, so I had already removed it. However, I feel confident the material under the fingerboard extension could be removed in the same way. Here you would definitely need heat. Removing the neck when you don't have to is a big step and worth avoiding if at all possible., but you may still feel it is worth removing the neck. This is because removing the top destabilizes the guitar and, in consequence, may well change the neck angle - I had this problem with a Gibson 12 string which needed a new top. Basically, once the top is off, the neck is held by the block, which is now supported only by the back and sides, and you have no idea how much it is flapping about as a result. You could find that you've retopped but the neck angle has changes so much the beck needs resetting. I'd probably take the neck off.

3 I If you decide to keep the neck on, it should be easy to get underneath it with palette knives and  then cut the top material off level with the heel block. I would not try to get the top material between the heel block and the neck out. Instead. I would pare away about 1/8 inch of that material at each side of the heel block with the aim of inserting the relevant part of the new top into the groove.

4 Make a new top (including braces) exactly as you would for a new build. This is the easy part.

5 Cut the top as follows: as near as possible to the size needed to make it fit inside the binding. If the braces on the original were inset into the linings, they should be cut to that size. The top size does not need to be exact, as you will be eventually routing purfling, which will cover any errors, but it has to be close so that there is a good fit on the linings. If you decide to keep the neck on, you should make a small pocket in the top the size of the neck block with additional material to fit into the area you have pared away under the fingerboard extension by the neck block. The pocket should be no longer than the neck block. In other words, the now top is more or less an exact fit except under the fingerboard, where it stops a the heel block and slides into the grooves you have pared away. If you have the neck off and the entire old top off, there's no problem. You just fit it as exactly as you can. This takes multiple checks, paring away tiny amounts of material, regardless of whether the neck is on or off. It's not difficult, but you need to be patient. It cannot be bigger than the perimeter of the binding anywhere, of course.

6 Once you have the best possuble fit, stick it on in the usual way.

7 Rout a channel for the purfling using a cutter offset away from the perimeter by the width of the binding. I would not trust a fancy stewmac style rig for this. I used a dremel both times. The top doesn't have much of a dome and the dremel with a good router base will be fine. Go slowly and remember it is better to be slightly away from the binding rather than cutting into it. You always have another chance if the binding is intact because you can rout again for slightly wider purfling. If you cut into the binding that's harder to rectify. (Obviously it's best to be dead on, and that is doable!). I know this sounds a lot, but I'm just an amateur and I was able to do an exact replacement of the top and herringbone purfling while retaining the ebony binding, just by being slow and careful. If you decided to keep the neck on, the purfling channel near the neck needs to be marked and cut by hand.

8 Finish and position the salvaged bridge or a replacement in the same way as for a new build.

9 All this assumes you have wood bindings. If you have plastic, everything needs to be a lot slower, because you don't want heat buildup as that will end up melting the bindings, not cutting.

Gosh, I think that's it. Looks hard written down, but it's not as bad as you think. With the degree of damage you seem to have to the top, trying to get a top repair that looked OK would be a lot harder - a lot.

Good luck, and if you have any questions. get back to me. I think I took pictures of the process and I can see if I can find them if it helps. 

I'm sure more experienced members may have more to offer and more elegant solutions, but this really did work!

Cheers, Rob

[robnewell54]

What John Parchem said is a great alternative to what I suggested, although we are similar in some points; I didn't see his till I posted. Hopefully I added some useful detail. His comment about doing the whole thing in a mold is really important, but I would still be worried that the neck angle would be compromised without the top support. I guess it would be possible to preserve the purfling as well as the binding, but purfling is cheaper than time IMO, and I personally would struggle with so exact a fit. Also, my error in I forgot Phil mentioned he could get the neck off. That is best.

A couple of people mentioned rebinding. That's fine (and by far the easiest solution) as long as the orginal binding doesn't have anything fancy, like multiple inlay lines and mitres on the sides. Cheers, Rob

On Tuesday, June 25, 2024 at 6:01:24 AM UTC+1 pianb...@gmail.com wrote:

[windquest_one]

Hi all,

What Rob says is correct.  I replaced a top on a guitar that was over 100 years old.  The simply had to be saved.  It was ivory, and no way possible to replace it.  To size the new top, I stuck the new top to the old one with double sided tape and used my binding machine to trim the new top to size.  After the new top was trimmed to fit, remove it from on top of the old top.  I used the binding machine to cut the old top inside the binding down to the linings.  Then heat the old top and remove it in as many pieces as necessary.  Just be careful of the old binding which is still glued to the sides.  Anyway, at this point you should have a top that will fit.  Go ahead and brace and you will be ready to install the new top.

Dale