First Gibson rebuild

[pianoman89]

So a few weeks back I purchased a Gibson A1 that had been hanging around eBay for a while. The pics in the listing had the mando looking like it had really taken some bad abuse, but I was pleasantly surprised at its condition when I got it got it in. It is currently undergoing surgery, but the main issues were central to the neck only. Anyhow, I thought Id share some pics of the mando when it first came in. Ive taken step by step photos of the restoration process that I may compile into a blog if I get some time, but this semester of school has me deep in my books.

So for the before pics. And yes, that is automotive body filler reconstructing the neck.... some people...





Like I mentioned, the neck had real issues. The middle strip of ebonized wood had deteriorated to a material reminiscent of dried bread crumbs, in some areas just plain sawdust. So a neck removal was in order so I could replace with a much stronger piece of ebony.

[pianoman89]

Here are a few pics of the progress.

A close up of the bondo issue


bondo removed


The fingerboard was removed using alcohol. It popped loose from the neck very easily, but was a real pain were joined to the top...


I wasn't very impressed with the dovetail joint. A large void was filled with hide glue...


As mentioned above, the neck was the reason for disassembly. The center joint fell apart without any effort...


Removal of the center ebony, or ebonized material, before removing the neck made the process of neck removal much simpler as it could be removed one side at a time. This allowed wiggle room to work the neck loose from the joint in place of pressing the dovetail up out of its slot.



Here is a pic of the progress on the neck, also showing the area that was once defiled by bondo.

[Steve VandeWater]

Following this thread with interest. I can't wait to see it as you progress and ultimayely finish. It will be a gratifying experience I'm sure.

[Tom Haywood]

Nice work and pics!

[fscotte]

That's a very good looking dovetail. The void with glue is inconsequential.

[sunburst]

The "void" is the intentional gap at the end of the dovetail, without which the joint will not tighten and work correctly. It was not intentionally filled with glue, but instead glue was squeezed into the gap when the fingerboard was glued on.

[Pete Jenner]

The "void" is the intentional gap at the end of the dovetail, without which the joint will not tighten and work correctly. It was not intentionally filled with glue, but instead glue was squeezed into the gap when the fingerboard was glued on.

Were you there? Wow - you must be really old. Mind if I call you grandad?

[pianoman89]

The "void" is the intentional gap at the end of the dovetail, without which the joint will not tighten and work correctly. It was not intentionally filled with glue, but instead glue was squeezed into the gap when the fingerboard was glued on.

Thanks for letting me know John. I wasnt sure if it was intentional. Very interesting. Mind you Ive always been a violin guy, and Im sure you know how violin makers feel about any gap in the neck joint. However, its a totally different joint style as you know so I'm open to the idea. Is this also how new mandos ar built? I have also never seen a guitar's dovetail with such a void..

Thanks again for the feedback. I was definitely hoping some of the more experienced luthiers here would offer their thoughts.

[sunburst]

Yes, the violin mortise and tenon joint is a different joint from the guitar/mandolin tapered dovetail. The former relies on the side grain glue joint to each side as well as what strength it can get from the end grain glue joint at the end of the tenon. The later is a mechanical, self-tightening joint that uses the wedging action of the taper to draw the neck heel tight to the rim. If there is no gap at the end of the tenon, that can't happen. The difference in the amount of string tension is undoubtedly the reason the guitar and mandolin joints became what they are. The mortise and tenon of the violin holds up fine to the tension of 4 rather soft fiddle strings, but when we tune up 6 to 8 steel strings, the dovetail holds up better.
Except for a few rare cases, guitar dovetails have a gap at the end of the dovetail tenon. It serves, as I said, to allow the joint to tighten, and is also conveniently gives us a place to insert a steam needle to reverse the joint for neck re-sets.

[pianoman89]

Ok here are a few more pics, especially on the process of repairing the neck...

So here is the process of gluing the new ebony strip in the neck. The strip was glued one side at a time, and was thicker than needed when glued to the first side. This allowed me to slowly sand the strip down on a sanding board once the glue dried, and fit both halved of the neck back into the mandolin for fitting. The thickness of this strip was especially important as if it was not perfect, the fingerboard would no longer fit correctly. So it was sanded, placed back in the joint, checked against the fingerboard, and the process repeated until everything came together perfectly.

This is the dry test.


I always have a rule of thumb for glue.. I know there is much debate over this subject, but this is how I do it. If I want a very permanent joit, I use original tightbond. If it may need to be removed later, hot hide glue. When using tightbond, I wet the surface of the wood before gluing. This accomplishes a couple things. It opens the pores in the wood, and at the same time thins the glue a bit. Both of these results allow the glue to penetrate the wood better for a better joint.




Finally I was able to glue the two together. Here, the joint is glued with the neck in the joint. This acts as a clamp for the heel end, and also allows me to make sure the fingerboard lines up correctly. In fact, the fingerboard was clamped the whole time.

[pianoman89]

Next was the process of replace the wood where the bondo was. A block was shaped down to the correct shape fit the neck.



Now double sided tape was used to attach sandpaper to the actual block I would be gluing in. This will allow me to sand the neck to the exact contour of the filler block for a perfect fit.



Here it is just before glue...



And finally glue



Pics to come of how this process turned out!

[Timbofood]

Looking good so far, good luck with the rest.

[Rob Zamites]

Great job so far, I'm learning tons just looking at the photos...thanks!

[Hudmister]

Love the photos and the sharing of all the information. I've said prayers already that when it's all strung up it sounds great.

[pianoman89]

John I some how missed your reply. Thanks for the info. I was kinda thinking that direction. I guess I'll keep the gap there in that case.

[pianoman89]

Thanks to everyone for all the positive feedback. Ill continue posting pics here as the restoration progresses.

[talladam]

Love all the detailed pictures. Thank you!

[David Houchens]

When gluing the neck halves in the final step, were you able to angle clamps to place pressure at the back of the neck shaft? At the tip of the V? Or did the spools at the upper sides close it tightly? It looks closed up nicely.

[pfox14]

Really high quality work. Way to go.

[pianoman89]

Bryce it did close up nicely. I was concerned about that, but when I ran my dry run it pulled it closed so I went with it. It was super flush to begin with so the clamps were really there to keep the pieces aligned.

Thanks fox!