re-sticking hide glue

[Len Biglin]

Hi Guys , I have an old italian mandolin with some loose joints , will Titebond restick hide glue ok ? or should I cook up some hide glue ? and is it advisable to sand or scrape the old glue out? PS I dont need to tell you it's pretty pokey inside the bowl-backs.Thanks Len

[Pierre-Antoine Roiron]

I won't use Titebond for that kinf of repair. Adding some hide glue would remelt the old one. Be sure to clean the joints before.

[Len Biglin]

Ok thanks Pierre , I will try to run some sandpaper through the gaps then use hide glue , also do you know about the neck joint on bowl-back mandolins ? it has some cracks around the neck/body joint , and it's a mystery because they are lined with paper .Len

[Pierre-Antoine Roiron]

Follow Jim's advice below for joints' cleaning. I have no idea for you neck joint problem, I'm not familiar with mandolins, so I'd have to look carefully a guess if I had to work on it. Maybe some pictures would help.

[Jim Bancroft]

Hide glue is the only glue to use and you don't need to remove the old glue from the joint before regluing. If any dirt has entered the joint that needs to be cleaned the best you can.

You don't want to run sandpaper through the joint and change the joint contact. 

 

To clean the joint I'd first use compressed air and then clean with water and a toothbrush.

 

Jim

[Len Biglin]

OK thanks Jim and Pierre.

[Pierre-Antoine Roiron]

You're welcome. No pictures for your neck joint needing some thought?

[Len Biglin]

I will try to remember to snap some pictures thanks for the reminder Len

[Ned Knepp]

I have a bowl back mandolin  that I disassembled for the rosewood (patch material) but I won't have time to take and post any pictures until tomorrow afternoon at the earliest.

 

In a nut shell. Think of it as extending the heel shape on into the body for about 1 to 2 inches then cut a rabbit into it so the bowl material will lay flat with the heel and you have the basic idea. There isn't really an "joint" as we usually think of a dove tail or a head block separate from the neck. Overall, the design makes a lighter joint than separate block and neck but it also means that any bad glue at the joint where the staves meets the neck practically guarantees that the instrument will start to fold up.

 

I will try to get some picture tomorrow if no one else comes up with some.

 

Ned

[Eric Steven Johansen]

I am currently in the process of just such a restoration and have many photos. The head block is part of the neck as Ned pointed out. Here are some pictures. On most of the bowlbacks I've restored there is usually some mastic filler run around the neck to body joint to clean up any gaps between the ribs and neck heal. Mix some rosewood dust with hide glue for this. Work clean and use as little as possible.

[Eric Steven Johansen]

Also for reconstituting a hide glue joint I like to run a bead of boiling water through the joint first and follow that with some fresh hide glue. Here's a couple more shots of the restoration in progress.

[Len Biglin]

Thanks Eric , very helpful.Len