vega VIP banjo shell crack

[Lee Gendvilas]

Hello everyone. I'm looking for some direction in how best to approach fixing the crack in this banjo shell from a 1958 Vega VIP 5 string banjo. Please take a look at the pics and let me know your thoughts. I'm considering using hide glue but the crack through the label brought up concerns I had on how best to approach fixing this. Looking forward to your comments and thanks very much in advance.

[Frank Ford]

I think I'd use cyanoacrylate, thin soaked in first, followed by medium, clamped up well with curved cauls. There'll be some finish damage to contend with, but I think the CA would fill gaps and adhere better than hide.

The Martin decal and serial number of 1958 puts it in the late 1970s - most likely 1978

[Lee Gendvilas]

Hi Frank, thanks for the reply. Is this one of those jobs where I need to work fast in getting the cauls clamped on? Or should I do this in steps-use the thin CA to get into the small cracks and then medium CA to get the big one? Also, based on your knowledge, what type of finish did Martin use on the shell? And, do you think the decal will possibly be damaged more than it is?

[Paul Hostetter]

I certainly agree about the use of CA for this, exactly as Frank described, but would advise protecting the decal. My favorite substance for this is called Micromask, a blue waterbased rubbery paint that, once applied, CA can't touch or get under. Apply it very carefully with a brush, let it dry for half an hour, then cover it with waxed paper before tightening the caul. Once you're done, it rubs off like rubber cement, or wipes off easily and completely with a damp Q-tip. Make the inside caul as precise as possible.

That poor thing must have taken quite a whack to break through those plies!

[Lee Gendvilas]

Hi Paul, unfortunately the banjo wasn't whacked! I was trying to put in a pickup and noticed the crack right away. I took the banjo apart last summer and have not been able to get to it until now. BTW, where do you get Micromask? Also, I've never done this procedure before and am unclear of soaking the CA first then following with medium CA and clamping. Would you mind helping me understand? Thanks.

[Paul Hostetter]

Here's Micromask: http://tinyurl.com/3yvcquu There may be other places to get it cheaper, Google is your friend.

OK, step by step, here's how I would do it, but if you're at all uncomfortable doing this, turn it over to Frank!

1) take out the screw and bracket that are adjacent to the logo and the crack.

2) make the cauls, inside and outside. The inside one wants to be precisely the radius of what the broken-in surface was before the accident. It needs to be about long enough to fit between the two shoe nuts on either side of the one on the crack itself, the one you took out. The inside caul should be smooth, hard wood. The outside one needs a bunch of cork padding, but the fit needn't be precise.

3) Do a test run with them. Put a piece of plain paper between the caul and the inside surface. Use a good stout C-clamp right on the crack area. Make sure they compress just right, and the crack closes completely.

4) Paint on the micromask. Fine artist's brush, paint everything you don't ever want to CA to touch, which means everything that had lacquer on it. Don't let it go down into the crack. It goes on blue and dries clear, and it's rather hard to see after it dries, so use good light and pay attention.

5) Now put a piece of waxed paper between the caul and the inside surface and get the cauls loosely clamped into position, just enough to hold together but leaving the cracks open. Have Q-tips and paper towel handy. Use gravity to drizzle the thin CA into the opening in the six or so plies that are breached, and as it wicks down in there, chase it with a bit of the medium stuff and then carefully tighten the clamp. These two steps should take at most 45 seconds. And pay attention as the CA squeezes back up as you're tightening the clamp. Dab it, wipe it, don't let it run down the outside or anything! And pay attention because it might leak all the way though the entire rim and drip out the bottom. Tighten until the damaged area is all closed up. Let it sit overnight. Then take off the clamp, the cauls, the waxed paper, and clean up the micromask. If you got that part right, it should be really clean. Not as good as new, but as close as you'll hope to get.

[Lee Gendvilas]

Hello again Paul! Thanks so very much for taking your time to write the step by step instructions. After reading what you have written I feel confident I can do this. Just need some time to get the Micromask, make the cauls and do a few practice runs to get the timing down.

[Paul Hostetter]

Keep us posted. I think it'll be fine. Good luck!

[Lee Gendvilas]

Hi Paul. I just received two bottles of MicroMask yesterday and I'm planning on getting it done within the next week. Hopefully I will have a night open to get it done since as of August my district put me in a high school position (for the last 17 years I've been teaching elementary band) and now I teach band, strings, vocal music, and remedial classwork using computer software on the internet. So, when I get it done I'll let you know and post a photo.

[Paul Hostetter]

Carry on! And do keep us posted. (You're lucky your district still offers all that music!)

[Lee Gendvilas]

Hi Paul,

I was getting ready to practice the gluing procedure on the banjo shell and I noticed a few more separations in the laminations. None of them looked anything like the crack thru the decal so I took one of the cauls I made and tried to see if the caul was the same arc as the decal crack. The answer was no. I did try just clamping the cauls on the shell to see how much it would close the decal crack and it did very little to close it. I then took a piece of threaded rod, 2 washers and 2 nuts and tried, very carefully, to see if I could make the crack close and return the shell to having the same arc all the way around by exerting pressure from inside the rim (see pics). I was able to get it close but it is apparant that some wood is missing. I got to wondering if the shell was more oval than round. So I traced the inside diameter with the threaded rod in place and then without the threaded rod (see pic). The arcs are different. So my questions are: After I've glued the separations, I believe the shell will continue to collapse inward, so will the glue fail to hold against the force of it collapsing? Or, do you think once the glue is set it will keep it from collapsing? There is a metal ring on the outside of the shell. Will it make sense to put a similiar ring on the inside of the shell to help prevent it from collapsing? If I put a metal ring on the inside, will it alter the tone enough to notice? Or should I consider having a new shell (one piece instead of laminant) made? Or am I making to big of deal and glue it the best I can and call it done? Looking forward to your thoughts.

[Frank Ford]

I never expect a banjo shell to be perfectly round after it has been in service for a while.  The thinner the rim, the more oval it tends to get, and I've seen them much farther out of round than yours.

 

I'd put it back together and set it up. . .

[Lee Gendvilas]

Thanks very much Frank for your reply. I had a feeling I was thinking too much about getting it done. Happy Holidays!