Double bass resto/repair
- rocket
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Double bass resto/repair
Hi all, the opportunity arose so i thought it was time to broaden my horizons a bit the story goes, i saw this bass up for sale inc. bow, soft case/gig bag and damaged belly, picked it up for less than $300, someone has already had a go at it but a very amateurish job to say the least. The instrument has laminated plates, the label says it's 14 years old and maybe European, not sure if HHG was used in original build or not, now here's the cruncher,,, i want to pick the brains of my fellow forumites as to how i tackle this repair job. Do i take the belly off or the back to gain access to guts of the problem?if the belly has to come off do i take the finger board off first? If HHG isn't what is holding this together what is likely to be? and is heat and steam the most appropriate tool here?
Any pearls of wisdom offered here will be much appreciated.
Rod
Any pearls of wisdom offered here will be much appreciated.
Rod
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
www.octiganguitars.com
www.octiganguitars.com
Re: Double bass resto/repair
What the,
Is the whole black area a replacement section fitted (badly), or have they painted the original area black after attempting and failing at the repair of patching a split top at sound post location
It looks really bad
Is the whole black area a replacement section fitted (badly), or have they painted the original area black after attempting and failing at the repair of patching a split top at sound post location
It looks really bad
- rocket
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Re: Double bass resto/repair
Yes the area has been painted black to disguise the shitty repair attempt, i can feel a couple of chunks of timber has been glued beneath the area when feel inside the "f" hole, this will all have to come off and a proper repair done, so i'm hoping to be able to get inside and up close.
Rod.
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
www.octiganguitars.com
www.octiganguitars.com
Re: Double bass resto/repair
Okay, you may not have to remove top or back, but you do need to remove all the black paint so you can see what has been done, it appears they have cut a section out and then tried to graft a section in, is this right
Re: Double bass resto/repair
Silly silly way to repair a soundpost top split.
Once you have the old repair removed post photos and I can walk you through the repair process, you wont need to remove the top or back,
If you wanted to remove for repair, then you remove the back, I would use steam and a blade, at a guess it looks like a cheapie, so they would not have used hide glue, but used a yellow glue, so heat and steam, just go easy around the neck heel extension. It kind of looks like they have yanked the top of and made an absolute mess of it
Once you have the old repair removed post photos and I can walk you through the repair process, you wont need to remove the top or back,
If you wanted to remove for repair, then you remove the back, I would use steam and a blade, at a guess it looks like a cheapie, so they would not have used hide glue, but used a yellow glue, so heat and steam, just go easy around the neck heel extension. It kind of looks like they have yanked the top of and made an absolute mess of it
- needsmorecowbel
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Re: Double bass resto/repair
Looks like there's even a coat of finish plaster on there...
- matthew
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Re: Double bass resto/repair
Proper way to do it:
Take the belly off. Knife, wedges, steam. patience. All needed.
repair the broken areas - glue them together. You may have to press the belly curve out a bit. yes you can use epoxy on a ply bass
reinforce the whole belly area between the FFS with a spruce or pine veneer or patch. I'd use HHG.
plane down the edges of the patch.
Repair the edges of the plate damaged when you remove the top. Yes you can use epoxy to put new wood in there.
Clean up the rib edges and linings for new glue-up
Check bassbar is glued proberly and in OK shape. if not, plane it out and replace it with a new one.
Check the back and blocks for splits
you only want to remove the belly once.
replace the belly with HHG
refit new soundpost.
Away you go.
Take the belly off. Knife, wedges, steam. patience. All needed.
repair the broken areas - glue them together. You may have to press the belly curve out a bit. yes you can use epoxy on a ply bass
reinforce the whole belly area between the FFS with a spruce or pine veneer or patch. I'd use HHG.
plane down the edges of the patch.
Repair the edges of the plate damaged when you remove the top. Yes you can use epoxy to put new wood in there.
Clean up the rib edges and linings for new glue-up
Check bassbar is glued proberly and in OK shape. if not, plane it out and replace it with a new one.
Check the back and blocks for splits
you only want to remove the belly once.
replace the belly with HHG
refit new soundpost.
Away you go.
- matthew
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Re: Double bass resto/repair
PS I would NOT remove the back.
- rocket
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Re: Double bass resto/repair
Thanks for your advice Mathew, I suspect the first failed attempt at repairing this has used a foreign piece of material, ply as well, as the inner upper edge of the F hole is very thin and protruding out of line of the arching this i think would explain the use of a plaster type filler closer to the bridge area, i think a flat bit of ply was used and the only shaping was done with the filler. I was thinking of using some spruce stock as a patching material and carving to shape inside and out, do you think this will be compatible with the ply? also i'm fairly certain hhg wasn't used in the original build, is steam and hot knives and wedges and patience going to be sufficient for this novice bass repairer?
Cheers,,
Rod.
Cheers,,
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
www.octiganguitars.com
www.octiganguitars.com
Re: Double bass resto/repair
PS. I Would remove the back.
- matthew
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Re: Double bass resto/repair
Simso I'm sure you have excellent reasons for going in through the back door, but in my opinion it will only make things harder.
Rocket, if you did that, you would have to support the bass. top down. for quite a while, that fingerboard is really going to get in the way . But with the top off, you can throw the bass in the corner, do the top repair on your bench, and bring the rest out when its time to glue up again. Don't take the fingerboard off.
A double bass has very deep ribs and to do any useful work on the top you need to remove the top, as working any other way leaning into the instrument is really difficult. Plus, the back is usually glued on with stronger glue, and has a functional (and decorative) attachment to the neck at the button, even on cheap junky instruments. That is why i would do what I do on every instrument that comes in needing top repairs; remove the top. And yes, I only do double basses and cellos. You will need to remove the top to be able to remove all the bad repair wood, back to the original. Yes you will find yellow glue white glue and God knows what inside. Yes you will likely damage the ribs and the edges of the top when you remove it. But the top glues along a flat surface. So provided you can restore a solid gluing surface to the edges and the rib linings, its all good. (this is another reason for not removing the back; a back often has a bend at the upper bout and this makes it harder to get a good fit to reglue). I'd try a kitchen knife with a curved blade, dry, work it into the seam slowly and if you're lucky the seam will pop open. look for places where the seam may already be giving way ... good place to start the knife.
You'll need to work the knife, or knives, around the perimeter being carefully to only separate the joint, not cut into the top of the ribs. Heat may help. At each of the corners and at the top and bottom there's a block, but as its a BSO they probably won't be glued up all that well. But you will need to work the knife in carefully around the neck joint to get that area to release easily. take your time. You will damage the edges in places. But you just have to repair them again. Standard procedure.
I would repair the edges where the ply delaminates with good strong glue and any wood you care to use. Its only plywood. plane back to shape.
I would then remove all the bad repair wood on the plate with a chisel and a plane, and perhaps soak off the last .5mm. But you could just sand it out too. This is not a valuable instrument yet
Then I would reglue the top cracks, pressing between paper or foil and perspex to make sure the edges all line up nicely. You don't want to go shaping the outside if you can help it. Epoxy would be fine and fill any gaps nicely.
Then I would use say a 4mm piece of guitar top as a patch material and fit that to the inside of the top. You'll have to see how best to get a really good fit. Heat blanket and sandbags might do it. or you might need to chalk fit a bit. You can do it in two halves if that's easier. Go edge to edge between the FFs. Glue with whatever you like. I have used just radiata pine to patch a ply bass top before. It works fine. you do need to get a good fit though.
Then i would plane down the edges of the patch, leaving a nice flat bit where the soundpost will go.
I cant really tell from the pics but if the edge of the FF is misaligned this is most likely because the top is deformed. Much less likely someone has inserted flat ply in there (although i could be wrong) To get the top back into shape you need to press it back out to the right curve using heat and weights AFTER you reglue the crack but BEFORE you put in the patch.
Also check the ply at the back where the soundpost sits. if it is bulging you may wish, while the top is off, to add a veneer patch there too to spread the load. tis often done.
Hope this is useful.
There may be other repair methods, like pouring in bondo from the back, or falcate bracing, or magnets, or fibreglass, and these may work just fine, but it's not what I would do.
You have a pile of firewood there, you can rescue it with some time and care, and then you will have a cheap ply bass (about the cheapest money can buy) if the neck doesn't snap. Check the scroll chin and pegbox before you do any top repairs. If you have cracks there, yu'll need to fix them before its even worth having a go at the top. Is the fingerboard ebony? Hope so. Check by scraping at the cut end of the fingerboard with a chisel. If the paint comes off, its not ebony. Another thing you're going to have to deal with :-/
Have fun!
Rocket, if you did that, you would have to support the bass. top down. for quite a while, that fingerboard is really going to get in the way . But with the top off, you can throw the bass in the corner, do the top repair on your bench, and bring the rest out when its time to glue up again. Don't take the fingerboard off.
A double bass has very deep ribs and to do any useful work on the top you need to remove the top, as working any other way leaning into the instrument is really difficult. Plus, the back is usually glued on with stronger glue, and has a functional (and decorative) attachment to the neck at the button, even on cheap junky instruments. That is why i would do what I do on every instrument that comes in needing top repairs; remove the top. And yes, I only do double basses and cellos. You will need to remove the top to be able to remove all the bad repair wood, back to the original. Yes you will find yellow glue white glue and God knows what inside. Yes you will likely damage the ribs and the edges of the top when you remove it. But the top glues along a flat surface. So provided you can restore a solid gluing surface to the edges and the rib linings, its all good. (this is another reason for not removing the back; a back often has a bend at the upper bout and this makes it harder to get a good fit to reglue). I'd try a kitchen knife with a curved blade, dry, work it into the seam slowly and if you're lucky the seam will pop open. look for places where the seam may already be giving way ... good place to start the knife.
You'll need to work the knife, or knives, around the perimeter being carefully to only separate the joint, not cut into the top of the ribs. Heat may help. At each of the corners and at the top and bottom there's a block, but as its a BSO they probably won't be glued up all that well. But you will need to work the knife in carefully around the neck joint to get that area to release easily. take your time. You will damage the edges in places. But you just have to repair them again. Standard procedure.
I would repair the edges where the ply delaminates with good strong glue and any wood you care to use. Its only plywood. plane back to shape.
I would then remove all the bad repair wood on the plate with a chisel and a plane, and perhaps soak off the last .5mm. But you could just sand it out too. This is not a valuable instrument yet
Then I would reglue the top cracks, pressing between paper or foil and perspex to make sure the edges all line up nicely. You don't want to go shaping the outside if you can help it. Epoxy would be fine and fill any gaps nicely.
Then I would use say a 4mm piece of guitar top as a patch material and fit that to the inside of the top. You'll have to see how best to get a really good fit. Heat blanket and sandbags might do it. or you might need to chalk fit a bit. You can do it in two halves if that's easier. Go edge to edge between the FFs. Glue with whatever you like. I have used just radiata pine to patch a ply bass top before. It works fine. you do need to get a good fit though.
Then i would plane down the edges of the patch, leaving a nice flat bit where the soundpost will go.
I cant really tell from the pics but if the edge of the FF is misaligned this is most likely because the top is deformed. Much less likely someone has inserted flat ply in there (although i could be wrong) To get the top back into shape you need to press it back out to the right curve using heat and weights AFTER you reglue the crack but BEFORE you put in the patch.
Also check the ply at the back where the soundpost sits. if it is bulging you may wish, while the top is off, to add a veneer patch there too to spread the load. tis often done.
Hope this is useful.
There may be other repair methods, like pouring in bondo from the back, or falcate bracing, or magnets, or fibreglass, and these may work just fine, but it's not what I would do.
You have a pile of firewood there, you can rescue it with some time and care, and then you will have a cheap ply bass (about the cheapest money can buy) if the neck doesn't snap. Check the scroll chin and pegbox before you do any top repairs. If you have cracks there, yu'll need to fix them before its even worth having a go at the top. Is the fingerboard ebony? Hope so. Check by scraping at the cut end of the fingerboard with a chisel. If the paint comes off, its not ebony. Another thing you're going to have to deal with :-/
Have fun!
Last edited by matthew on Tue Aug 12, 2014 9:42 pm, edited 2 times in total.
- matthew
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Re: Double bass resto/repair
... you'll need a few dozen quick release clamps, or 10" spool clamps to reglue the top. there's a trick to that. do the repair and then i'll tell ya what it is.
-
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Re: Double bass resto/repair
I am definitely no expert...but why not take the challenge of making an entire new soundboard? I have seen a cheap plywood bass with a damaged top rebuilt with a King Billy or Huon pine top (not sure which) by Wooragee violin maker Kevin Williams. Sounds great and much improved. By the way, Williams was an apprentice of A.B.Smith, a famous Australian luthier renowned for his violas. Kevin's apprentice Warren Fordham is now a very well known maker living, I believe, in Tasmania.
"Everything I say on the topic is based solely upon inexperience and assumption!"
- rocket
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Re: Double bass resto/repair
Well i suppose if i screw up this repair job on the belly without ruining the sides making a new top is an option!!
Rod.
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
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- matthew
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Re: Double bass resto/repair
not a bad idea to make a new top if you feel up for it. but not Huon pine or King Billy. you need a slab 45mm thick ... what if you screw up?
western red cedar works really well but you need to hunt for some nice thick quarter sawn bits.
western red cedar works really well but you need to hunt for some nice thick quarter sawn bits.
- rocket
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Re: Double bass resto/repair
It's been a while but i've finally started on this repair job, some pics to follow ,,, but the top really is in a bad way, it's a laminated top and when it was impacted part of the lamination layer has been ripped off inside for about 600/700 long, the original repair was a very bad attempt, 3 or 4 layers of ply wood and a coat of plaster filler.
I'll take some pics and get them on here soon!!
Cheers
Rod.
I'll take some pics and get them on here soon!!
Cheers
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
www.octiganguitars.com
www.octiganguitars.com
- rocket
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Re: Double bass resto/repair
i am open to any technical advice that anyone may have in regards to procedures that might be adopted here!!
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
www.octiganguitars.com
www.octiganguitars.com
Re: Double bass resto/repair
Take it to the home renovation forum buddy!!rocket wrote:....... the original repair was a very bad attempt, 3 or 4 layers of ply wood and a coat of plaster filler.
I'll take some pics and get them on here soon!!
Cheers
Rod.
Martin
Re: Double bass resto/repair
Simply a graft needed
- matthew
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Re: Double bass resto/repair
forget repairing that top. I promise you it will not work out. make a new cedar or pine top and it will sound fab.
- rocket
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Re: Double bass resto/repair
Thanks for this very good advice Mathew, i thought i'd follow this with a bit of a variation rather than invest more time and money on building a new top for it.matthew wrote:Proper way to do it:
Take the belly off. Knife, wedges, steam. patience. All needed.
repair the broken areas - glue them together. You may have to press the belly curve out a bit. yes you can use epoxy on a ply bass
reinforce the whole belly area between the FFS with a spruce or pine veneer or patch. I'd use HHG.
plane down the edges of the patch.
Repair the edges of the plate damaged when you remove the top. Yes you can use epoxy to put new wood in there.
Clean up the rib edges and linings for new glue-up
Check bassbar is glued proberly and in OK shape. if not, plane it out and replace it with a new one.
Check the back and blocks for splits
you only want to remove the belly once.
replace the belly with HHG
refit new soundpost.
Away you go.
I got the top off ok but did damage it a bit, fixable though, fitted a patch, replaced veneer inside and reinforced with c/f tape. i still need to replace some damaged bits, some by me and some by others, looks like it,s been stood on, edges of middle bout are damaged a bit.
Cheers
Rod.
Like I said before the crash, " Hit the bloody thing, it won't hit ya back
www.octiganguitars.com
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- slowlearner
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Re: Double bass resto/repair
You're a better man than me Gungadin...
What a huge mess you've had to clean up there. Well done.
What a huge mess you've had to clean up there. Well done.
Pete
- rocket
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Re: Double bass resto/repair
Clearly not a hot topic this one, some might think that it's a time waster but i took it on as a project for some experience and it's proving to be just that.
I had a little trouble maintaining an even margin from the top to the sides but i managed to get it back on ok using hhg, refitted the bridge and sound post and strung it up, i intend to keep it strung for a few weeks and inspect for any signs of failure in the belly, and if it stands up to the test i'l then proceed with the new finish.
Cheers
Rod.
I had a little trouble maintaining an even margin from the top to the sides but i managed to get it back on ok using hhg, refitted the bridge and sound post and strung it up, i intend to keep it strung for a few weeks and inspect for any signs of failure in the belly, and if it stands up to the test i'l then proceed with the new finish.
Cheers
Rod.
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Like I said before the crash, " Hit the bloody thing, it won't hit ya back
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- matthew
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Re: Double bass resto/repair
Looks like as respectable a repair as you'd hope for on a bass like that!
Aligning the overhangs is a lot easier of you place the bass top upside down on some trestles, then fit the body over it. You can see the overhangs clearly and adjust the clamps all around till its right. Then loosen a few clamps at a time and work the glue in on a spatula, and you don't get any drips on the inside.
And that patch doesn't look too bad from the outside. Well done!
Aligning the overhangs is a lot easier of you place the bass top upside down on some trestles, then fit the body over it. You can see the overhangs clearly and adjust the clamps all around till its right. Then loosen a few clamps at a time and work the glue in on a spatula, and you don't get any drips on the inside.
And that patch doesn't look too bad from the outside. Well done!
Re: Double bass resto/repair
No such thing as a time waster, everything we do teaches us new things, even if we have done it before we learn more by doing it again.
Clearly you have learnt a lot in this repair, it will be good when all the finish lacquer work is done
Steve
Clearly you have learnt a lot in this repair, it will be good when all the finish lacquer work is done
Steve
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