High Action after glueing back together

[Oli Emmett]

So unfortunately my mandolin was sat on and snapped in half.
Luckily it snapped along where it had been glued before. I had a friend who had instrument glue and vices. We glued it back together, but now the action is really high. On the advice from 2 different people who've worked with luthiers, I've sanded down the bridge, but the action was really high. They suggested a couple millimetres, I've probably lowered if by 4 now and it's still a problem.
Is it a good idea to keep lowering the bridge or am I going to ruin it at some point?

[Nevin]

Pictures would be a big help.

[Oli Emmett]

There's not an option to add photos and I don't have another website or something to link them from, :/

[pops1]

There's not an option to add photos and I don't have another website or something to link them from, :/

If you look when you respond to a thread the third from the right image is for inserting a photo or image, just click on it.

[Oli Emmett]

The option doesn't show up on the smartphone site, so took me a while to find. I didn't really know what to photograph, but this shows basically whats going on.

[Oli Emmett]

The option doesn't show up on the smartphone site, so took me a while to find. I didn't really know what to photograph, but this shows basically whats going on.

[bernabe]

If the photos are after the "repair'. The neck is set at a different angle due to the gap between the heel and body. The neck needs proper resetting.

[multidon]

What kind of mandolin is it? It looks like some type of pancake flat top. What kind of neck joint does it have? When you say it "snapped" was it just a butt joint at the separation, or was there some sort of tenon, dovetail, dowels or bolt? If one of those was present and it snapped through, you are screwed. Glue alone will not hold against the pull of the strings.

I would not have tried to fix something that major myself. You should take it to a real luthier, not a friend with glue and clamps. Possessing glue and clamps does not make one a luthier. If it's worth fixing it's worth fixing correctly. If it's not I would take the loss and move on. If the dovetail/ tenon or whatever is broken it might need a new neck (expensive, perhaps 500 dollars or more).

I bet the neck angle was not set THAT incorrectly. Rather, the joint shows evidence of failure and movement post-"repair". Evidenced by the dried glue visible in the gap that developed.

[Oli Emmett]

The friend is an amateur luthier which is why he had the kit. He built himself an acoustic bass guitar among other things and it was an inspiring peice of work which is why I let him try. I've showed it to a luthier and he says the repair job looks to be well done, and advised me to lower the bridge, but I can't tell if it's getting worse.

[Oli Emmett]

It's an Ozark army navy mandolin. When it broke there were three bolts cut from the wood that had corresponding holes, and it had snapped pretty much as it had been glued originally, so we just glued it back the same way, it was perfect at first and became worse in the next days, but like I said, I don't know if it's getting worse

[Folkmusician.com]

Hey, it looks like your friend can get some more lutherie practice!

Unfortunately, that is going to need to be taken apart and redone. It will be an ordeal to get the glue off and prep a clean surface.

Lowering the bridge reduces the string tension, causing less downward force. You do need some break angle to hold the bridge down and drive the top. lowering it more may or may not cause an issue. before lowering it more, I would make sure the neck is stable and not going to pull off. If it is solid, lowering the bridge may work for now. Ideally, the neck needs to come off and be attached correctly.

[multidon]

I am still not getting a clear picture of the neck joint itself. You say it has "three bolts cut from the wood" that have "cirresponding holes". What does "cut from the wood mean, exactly? My belief is that those three bolts were doing the real work of holding the neck on, not the glue. If you just stuck the bolts into their "corresponding holes" and the threads in the wood of the neck were stripped as a result of the trauma it received, then nothing was holding the joint but glue and failure of the joint was a predictable certainty. There must be some kind of mechanical joint there- dovetail, dowels, tenon, bolts, whatever. You will have to take it apart and start over as Robert says. All the old glue will have to be removed. All of it. The holes in the neck for the bolts will probably have to be filled with glued in dowels so they can be re- drilled with clean holes so that the bolts can cut new threads. I would recommend making sure everything lines up correctly with the bolts alone before using any glue. Hot hide glue would be great if your friend knows how to use it but otherwise Original Titebond (red) would be the way to go. Properly done, this repair requires no clamps. The bolts are also the clamps. Hope this is all helpful.

[sblock]

Maybe the OP thought that a dowel was a "bolt cut from the wood."? Or maybe "cut from the wood" just means that a metal bolt has stripped out of the wood?

[multidon]

I would imagine it was the later. My estimation of the situation is the metal bolts pulled out forcibly from their holes during the incident, stripping the threads. The OP's friend just stuck the bolts back into their stripped holes and glued it. Glue alone has no hope whatsoever of holding that joint against the pull of the strings. The holes would have to be plugged and redrilled for new threads as stated above. With no dovetail or tenon the bolts are doing the real work, not the glue.

Doesn't matter, really. The OP has disappeared, as sometimes happens in cases like this. He was a new member who joined specifically to have this particular problem addressed, evidenced by the fact that he has not started any new threads other than this one and has not commented on any other threads except this one. And most likely he didn't like the answers he got so he may not be back. I've seen it happen more than once.

We now know that it is an Ozark Army Navy Style, which tells us that this mandolin cost £175 new (about $230 US) and a proper professional repair would exceed the value of the instrument by a considerable margin. So it is a total loss unless a talented amateur luthier takes it on as a learning project. Clearly the friend in this case was not aware of the proper repair technique. Just putting on a bunch of glue and keeping your fingers crossed is not the way to go. I bet that, minus the bolts, it's just a butt joint.

Sometimes, it's better to just walk away.

[kkmm]

The center photo of post#6 tells the real reason: with a gap like this, the neck angle is not proper and cause the high action. Just that simple. Maybe the OP got that from this thread and is working on it.