MIMF

A friend of mine contacted me a little over a year ago about how to fix a bad break head stock that had already been re-glued at least twice before he bought it. It's a 1921 Gibson A mandolin, with a truss rod. He got a great deal on it but was unsure of how to proceed with a headless mandolin in one hand and the head stock in the other. The original break was already bad, being a mostly an end grain break. I coached him over the phone, as he lives a few states away, and went over how I would approach it. He got things nicely cleaned up and glued it up with epoxy, which I told him to use, but he got hardware store epoxy and not the West System epoxy I told him to get. Once he got it strung up, it didn't last but a few days and the crack started to open again. He was in my area this past August and left it with me to see what I could do.

Epoxies are not all the same and if he would have used the West System epoxy, I wouldn't be posting this. West System gets very hard unlike regular two part mix that dents easily with a finger nail and can creep under tension. When Colloidal Silica is added to the mix, it also provides gap filling strength. It can also be tinted with Trans tints, which helps the finished job look better. If there are equals to West System, I am not familiar with them and will only use the West System for any instrument work where epoxy is determined to be the best choice.

I took images along the way to share with the mandolin's owner and thought I would post my process for anyone interested. I didn't take any before images but the only thing relevant I can add is that the entire head stock, front, back and sides, was sprayed out rattle can Black.

I heated the once again failed repair and it rather easily came back apart. The next step is to use dental tools, Exacto knife, whatever to mechanically remove as much glue as possible. This step is important to not only get the parts to fit back together correctly but also to ovoid gluing glue to glue as much as possible. You can see that there isn't much to work with...
I think I only get 5 attachments per post, so will have multiple posts to put all of this up.

The parts lined up well enough and stayed in place well enough to only require a very simple clamping strategy. The West System epoxy has been thickened with Colloidal Silica and tinted Brown. Where wood was missing and I didn't want epoxy fill to show I pieced some bits of Mahogany.

Pieces have been added, I do some sanding and then get set up to reinforce the head stock with carbon fiber rod. The router jig board is a piece of 1/2" MDF, laminated both sides with plastic laminate. Double stick tape holds quite well to the laminate, keeping my setup simple.

The carbon fiber rod is glued in with West System epoxy. Epoxy is the best adhesive for carbon fiber and bonds well with it. Next step is to make an Ebony face plate to cover the reinforcement work and also add additional strength to the repair. I ordered a stock face plate from LMI and thinned it with a router set up. I plotted the approximate truss rod hole location and roughed it out so I wouldn't have work so hard at final shaping, a time saver. The face of the head stock is routed down the thickness of the face plate that will be added.

The Gibson mandolin head stock face would have originally been painted Black but the repair is all about making it a player again.

The overlay is glued on with hot hide glue, shaped and tuner holes drilled though.

I stained the bare wood and sprayed it with lacquer.

The decision to reinforce with the carbon fiber rod, is the main component that will make this repair enduing. There was quite a bit of wood missing and as can be seen in my images, there was precious little wood to bond too that wasn't end grain. Carbon fiber is pretty easy to work with and is a good, light weighty solution when a little extra structure is needed.
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Wow! I don't know why I am just now seeing this, but nice job. looking at the first picture would have been enough for me to decide to make a new neck. Good save.

Thanks for posting! Like Bryan said, that’s a great save!

Thanks guys. I'm a bit of a sucker for a hard luck case and not afraid of challenges. This one took right around 14 hours, start to final set up but turned out really well. It set up easily and plays quite well, sounds great too! My friend that owns it took up banjo building and I'll likely barter for some nice instrument wood, tooling or something else instrument related for compensation.

Wow! My hat is certainly off to you. Thanks so much for an extremely informative post. I've got an early Gibson F-2 Triple point with a broken headstock and will certainly steal some of your technique for that repair. Nothing as radical as your's, but I can see I need to get some West Systems Epoxy in the shop!

Thanks Chris,

You should check this out too. I posted a few images of my project over at the Mandolin Cafe and John Hamlett, a skilled builder and repairer, responded with this link of a very similar process of an F2 repair.

https://www.mandolincafe.com/forum/thre ... -F2-repair

Pretty, pretty, pretty good!

Hey Paul, I just got back on the site and looked at the video you posted. Thanks!

Paul, very nice job, on a difficult repair! It's always nice to see a damaged, good instrument brought back to playing condition.

Thats so much better than the typical horrible splines on the back of the headstock

Very nice job!

Any reason you didn't put a veneer on the back of the headstock?

Keith Howell wrote: ↑Sun May 09, 2021 4:46 am Very nice job!

Any reason you didn't put a veneer on the back of the headstock?

Yes, did this project close to give away for a friend feeling a financial pinch from the pandemic. Had enough time invested already!

Thanks all for the replies.

Thought about this after I posted that, to answer your question better, I should have mentioned that I did consider an overlay on the back of the head stock. The carbon fiber splint repair and head plate overlay is strong enough without doing the back. It didn't need it and didn't have one originally...

Good job Paul! Very interesting to read through and great pictures of the process. Thanks!