Double Bass Can you help an idiot fix his own crack?

[Muddytone]

Hi there kindly experts

I need some help/advice with a small but slowly growing crack on the button/edging/(not really honest to call it purfling) of my (cheap, £330 with crack, Gear4Music) upright bass (see photos). It's maybe 35mm in length total and slightly reducible with light pressure. It's grown 10mm over the past three months (away from the button) with the change in season, but otherwise hadn't changed in over six months. Here's why I'm posting here and not taking it to a luthier in person: there isn't a luthier near me (there is a violin maker not too far away, but ...), I'm far from flush with cash (struggling nurse), I'm not too happy about carting it around in a taxi (won't fit in my car), it doesn't seem like a take-the-back-off job, and I do have some hide glue. And duct tape (joking - kinda). I'm also keen to learn if I can do it. Only thing I'm anxious about is clamping it whilst the glue cures (if I need to do that), and I do not have much experience with hide glue. There is no movement of the neck, nor any resonance issues - as far as I can tell no problems (yet) at all other than the darn crack! I think the crack originally is more likely due more to cheap construction than having taken a bad knock at some point in the past. However, the previous owner was a psychobilly drinker ...



Many thanks for any advice!

 

[Clark Dark]

If it moves with light pressure I would take it to have it repaired by a pro. I'm thinking that a rattle or buzz due to the corner unsealed could develop.

 

[JBarz]

Here’s what I’d do, but I’m a hack beginner (and also and idiot!).. buy a hot hide glue pot and the strongest glue you can get ($150), some solid long strong locking clamps ($20x2), and a syringe ($3)... mix up the glue kind of thin, insert in crack liberally with syringe, clamp for 24 hours, done deal. No sweat. Have confidence - cheap basses are made to futz with!

 

[bherman]

I do alot of woodworking, but not to my bass (its not a cheap one). There are two key issues to repairing cracks 1) getting glue into the crack, and 2) clamping it while it dries. The second part is pretty straightforward looking at your bass - you need a bar clamp that's long enough to span from front to back (see photo below). In the US, we have an outfit called Harbor Freight that sells cheap tools - a clamp like this can be bought for around $6. Pro-level clamps are much more costly, not sure if you can find a cheap one (or borrow one).

Getting the glue where it needs to be is trickier - you need to get the crack open enough to get glue onto the two surfaces to be joined, but obviously you don't want to make the crack worse in doing so. You might be able to use a very thin putty knife to gently separate the crack, and squirt in some hide glue. Don't give in to temptation and use super glue, it'll flow in fine and will work, but will make it harder to separate if down the road, it needs a more substantial repair. At least from the picture, this all looks doable.

 

[Keith Rawlings]

Here’s what I’d do, but I’m a hack beginner (and also and idiot!).. buy a hot hide glue pot and the strongest glue you can get ($150), some solid long strong locking clamps ($20x2), and a syringe ($3)... mix up the glue kind of thin, insert in crack liberally with syringe, clamp for 24 hours, done deal. No sweat. Have confidence - cheap basses are made to futz with!

This guy knows what he’s doing. Listen to him.

 

[David Potts]

Is the crack just on the one side that you are showing or does it go right the way around the join between the top of the back and the neck heel? It looks like the scroll has taken a knock that started the crack which looks more like a delamination of the ply back. Yes, getting glue in far enough without doing more damage will be tricky. A very thin artist's palette knife or a very thin old table knife may be able to wedge the crack open enough without breaking a chunk out of the back. You might be able to hold the crack open by making some little fine wedges from match sticks then use the same knife to work hot hide glue in quickly before clamping then sponging off any glue that is squeezed out.

Before you start make a wedge to tape to the fingerboard that will neutralise the backwards angle of the fingerboard and stop the clamp foot from slipping when tightened. Also tape a piece of cardboard to the top of the back to protect the wood and varnish from the other clamp foot. An emergency glue pot is an old tea cup standing in a small saucepan of hot water. You do not have to make up much glue, probably a teaspoon of dry to which is added a little cold water to just cover, stand and absorb for a few hours before melting. Use a small throw away stick to stir as it melts, adding a few drops at a time of hot water from the sauce pan if too thick and treacley, ending up with something like hot thin honey As you heat the water it does not take a very high temperature to melt the glue so do not over cook. Heat your knife in the hot water before dipping in the glue to help work the glue into the crack as far as you safely can before it starts to gel. You can also quickly follow up with the hot wet blade to refresh the glue if necessary before quickly clamping. Leave the clamp on for about 24 hours.

Al the above presumes that you have never used hide glue before. If too daunted take the bass to the luthier. Please do not resort to wood screws or other glues no matter how cheap the bass. Fix the crack ASAP because the strength of the overall neck joint to the bass body relies heavily on the leverage provided by this area.

Best wishes, DP

 

[1st Bass]

What David said!

 

[unbrokenchain]

I'm not helping anyone get a crack fix

 

[james condino]

"Crackalachia"....

You can make your own hot hide glue pot for $3 worth of parts available at any thrift store in the US. The prices that they charge for those things in the big supply houses is obscene!

H#!!, I've cooked it in two stacked beer cans (double boiler effect) on top of a juniper fire while living with a hippee chick in a teepee in the high desert back in the day....

 

[GretschWretch]

How can anybody not like a thread whose title is a masterpiece of ambiguity, and by post nine we are into imagery that is . . . troubling. To me, high desert, sand, and crack does not sound like a marriage made in heaven.

 

[Muddytone]

If it moves with light pressure I would take it to have it repaired by a pro. I'm thinking that a rattle or buzz due to the corner unsealed could develop.

A rattle or a buzz are fears. I guess scientifically there must be a tiny one already that I can't hear (might even be fairly obvious on a better instrument)

 

[Muddytone]

Here’s what I’d do, but I’m a hack beginner (and also and idiot!).. buy a hot hide glue pot and the strongest glue you can get ($150), some solid long strong locking clamps ($20x2), and a syringe ($3)... mix up the glue kind of thin, insert in crack liberally with syringe, clamp for 24 hours, done deal. No sweat. Have confidence - cheap basses are made to futz with!

Man, not a word I didn't want to hear! Thanks - I will futz away happily

 

[Muddytone]

I do alot of woodworking, but not to my bass (its not a cheap one). There are two key issues to repairing cracks 1) getting glue into the crack, and 2) clamping it while it dries. The second part is pretty straightforward looking at your bass - you need a bar clamp that's long enough to span from front to back (see photo below). In the US, we have an outfit called Harbor Freight that sells cheap tools - a clamp like this can be bought for around $6. Pro-level clamps are much more costly, not sure if you can find a cheap one (or borrow one).

Getting the glue where it needs to be is trickier - you need to get the crack open enough to get glue onto the two surfaces to be joined, but obviously you don't want to make the crack worse in doing so. You might be able to use a very thin putty knife to gently separate the crack, and squirt in some hide glue. Don't give in to temptation and use super glue, it'll flow in fine and will work, but will make it harder to separate if down the road, it needs a more substantial repair. At least from the picture, this all looks doable.


View attachment 4282867

Thank you very much! I have a couple of cheap clamps like the one you describe, I'm just worried about over tightening them - they use a trigger mechanism instead of a screw - but Mr Potts below helps with this. Working in a hospital I can get my hands on some fine syringes and scalpels etc. but will clearly have to practice with the glue first. And I will be strong, and resist the superglue. Thanks again!

 

[GretschWretch]

A point about clamps and hide glue: you do not want to crank the clamps down as far as they will go and generate a lot of squeeze out; just clamp down until you feel some resistance. A property of hide glue is that as it cures it will draw the two glued surfaces together. When you go to remove the clamps they should be looser than you left them, because of this adhesion process.

Also, remove any squeeze out after clamping with a moist cloth. Don't wait until it dries and above all, do not peel dried squeeze-out from the bass. You will remove the glue, but also you risk removing the finish. Ask me how I know.

 

[Muddytone]

Is the crack just on the one side that you are showing or does it go right the way around the join between the top of the back and the neck heel? It looks like the scroll has taken a knock that started the crack which looks more like a delamination of the ply back. Yes, getting glue in far enough without doing more damage will be tricky. A very thin artist's palette knife or a very thin old table knife may be able to wedge the crack open enough without breaking a chunk out of the back. You might be able to hold the crack open by making some little fine wedges from match sticks then use the same knife to work hot hide glue in quickly before clamping then sponging off any glue that is squeezed out.

Before you start make a wedge to tape to the fingerboard that will neutralise the backwards angle of the fingerboard and stop the clamp foot from slipping when tightened. Also tape a piece of cardboard to the top of the back to protect the wood and varnish from the other clamp foot. An emergency glue pot is an old tea cup standing in a small saucepan of hot water. You do not have to make up much glue, probably a teaspoon of dry to which is added a little cold water to just cover, stand and absorb for a few hours before melting. Use a small throw away stick to stir as it melts, adding a few drops at a time of hot water from the sauce pan if too thick and treacley, ending up with something like hot thin honey As you heat the water it does not take a very high temperature to melt the glue so do not over cook. Heat your knife in the hot water before dipping in the glue to help work the glue into the crack as far as you safely can before it starts to gel. You can also quickly follow up with the hot wet blade to refresh the glue if necessary before quickly clamping. Leave the clamp on for about 24 hours.

Al the above presumes that you have never used hide glue before. If too daunted take the bass to the luthier. Please do not resort to wood screws or other glues no matter how cheap the bass. Fix the crack ASAP because the strength of the overall neck joint to the bass body relies heavily on the leverage provided by this area.

Best wishes, DP

I cannot thank you enough - I will no doubt be re-reading this dozens of times. The crack doesn't reach the very too/pinnacle nor the other side, and I think you are spot on about the delamination. And my ignorance of hide glue ... Your advice will be invaluable and relieves many of my worries about damaging the thing further when I clamp it. I will get wedge cutting. And ASAP!
Thanks again.

 

[Muddytone]

A point about clamps and hide glue: you do not want to crank the clamps down as far as they will go and generate a lot of squeeze out; just clamp down until you feel some resistance. A property of hide glue is that as it cures it will draw the two glued surfaces together. When you go to remove the clamps they should be looser than you left them, because of this adhesion process.

Also, remove any squeeze out after clamping with a moist cloth. Don't wait until it dries and above all, do not peel dried squeeze-out from the bass. You will remove the glue, but also you risk removing the finish. Ask me how I know.

many thanks - I did wonder that about the hide stuff. You may have saved me again there. But I think I might hold off asking you how you know until after I've had a go at this

 

[Muddytone]

Update for the interested:
Performed as above a few days ago, with (some?) success. However, I think perhaps my glue was a little too runny; it went through a very small gauge syringe, and although the crack is no longer moveable (can't squish it anymore) and sounds solid when I give it a little tap, it's still very much there with no glue obviously visible - and I'm torn between accepting that it is fixed and applying a little varnish, or applying more, thicker glue at the risk of damaging what is already probably fixed. I guess if left for a few more days or so whilst I grow confident with it I'll still have these sweaty palms, vacant eyes and preoccupied shuffle, will still mumble about crack when people ask what's wrong with me ... but most likely it is job done. And I know what to do if it ain't. Thanks!

ps that hide glue smells awful melting, somebody could've warned me about that ...

 

[David Potts]

"Perfection is within my reach but slightly out of my grasp" said some wise owl. You might be able to fill and colour the still-visible crack line before touching up with varnish and a fine brush. Then you will see if it starts to happen again.

Well done!

 

[Muddytone]

"Perfection is within my reach but slightly out of my grasp" said some wise owl. You might be able to fill and colour the still-visible crack line before touching up with varnish and a fine brush. Then you will see if it starts to happen again.

Well done!

Thanks! Again! Will happily do so today.