I tried repeatedly to solder the broken margins but even expensive solder supposedly just for pot metal would not stick at all. I finally repaired the breaks with epoxy, which is holding up well. I tried replating it with no success. First, you must coat pot metal with copper so the nickel plating can adhere. The copper plated out well in some spots but in other places the plating solution turned the pot metal into a black, chalky residue. Repeated attempts began to etch the flange so I had to give up. I painted the flange silver and sealed it with several coats of lacquer. It is not as sophisticated as I might have liked but at least the corrosion is arrested for a while.
For reasons I don't understand, the inside diameter of the flange is about 1/4" larger than the outside diameter of the bottom of the rim. The former owner had the neck mounted such that it pinched the flange all the way back against the rim. I centered the flange on the rim and held it in place with some wooden shims. Later, we'll see that the heel had to be cut to fit the rim properly.
The original hoop was quite stout, being slightly less than 11/16” tall by 3/16” thick. I bought some brass strip stock from Online Metals (http://www.onlinemetals.com/), a good outfit that has a large variety of brass stock at reasonable prices. The closest available size is 5/8”(0.625") by 3/16”(0.1875"). This is a good match – the height difference of less than 1/16” was not a problem. The next trick was to bend this into a hoop.
I used a “ring roller” for this task. These gizmos are hard to find but Harbor Freight Tools (http://www.harborfreight.com/) sells a Chinese-made one for about $50. Two of the knurled knobs are geared to turn together, powered by a hand crank. The third knob is free-rolling, but its distance from the other two is adjustable. You crank the brass in horizontally and it is bent slightly. You get the diameter you want by adjusting the third roller up (smaller diameter) or down (larger diameter).
Above are some photos of this Medieval-looking device. It is easy to operate with a bit of practice. The photo below shows it in operation – I'm running a piece of mild steel stock through it (moving left to right) for the photo. Slick, huh?
I ran the 36” piece of brass bar stock through several times to get the diameter as close as possible. It looked like this:
Note that the knurled rollers dig into the brass, otherwise it wouldn't feed through the machine. The marks were not difficult to remove with the sanding drum on my generic Dremel-type tool.
Next, I beveled the ends and soldered them together. I measured the notch spacing from the flange and cut the notches. I made the first vertical cuts with a razor saw, filed out the material between the cuts, and finished shaping the notches with a Dremel tool to match the size and profile of the originals. I did a trial fit using a Mylar head I had handy. Looks like the fit is OK. I then plated it with a Caswell nickel plating kit, available from Caswell, Inc. (http://www.caswellplating.com/) They have lots of great stuff for metal plating for the hobbyist or small shop. A little buffing, and you have a handsome, heavy tension hoop that will last a very long time. Here it is on the finished instrument. I forgot to take a picture of it before putting it on the rim. D'Oh!
3. Rim/Tone Ring.
The rim just needed a little lacquer touch-up here and there. The rim has a simple tone ring made of steel rod. This required only rust removal with some steel wool.
4. Head/Flesh Hoop.
I put on a new good-quality calfskin head (photo shows mounting in progress). Mounting skin heads seems to be a mysterious, arcane art these days, but it is fun and interesting, really. One of these days, I'll do a pictorial “how-to” on the topic.
The banjo has a very pretty brass flesh hoop with a square in cross section. It also cleaned up nicely with steel wool and Brasso (a brass polish). Here's a close-up of a small segment of it:
I removed the rust with Rust-Oleum "Metal Saver" Rust Stripper and replated them, again with the Caswell nickel kit. A little buffing and they look pretty good. The nuts were OK. They are the only parts that didn't need any work except cleaning.
hammered out the dents and polished it up a bit.
It looks OK and is definitely DIFFERENT.
One nice thing is that it is easily removable with no tools and is quite
light. It is held in place by four spring-loaded
clips. Here they are all polished
up (left) and one mounted in the resonator (right) .
The fret wear was corrected by a light dressing and polishing. The heel plate was missing so I made a new one out of rosewood (visible in first photo in this section). The ivoroid binding needed re-glued at one place near the nut.
I cleaned up the plastic “Luxor” logo and re-glued it with tiny dabs of cyanoacrylate.
9. Tuning Machines.
I only needed to clean and oil them. I pirated replacements for the missing screw and bushing from an old junker in the back of the closet.
I rehabilitated the plating a little. I replaced the missing adjustment screw with a hardware store item. I chose the black anodized one to indicate that it was not the original.
I filled in the chip at the 1st string notch with gel-type cyanoacrylate glue. The repair is not very noticeable.
The string notches were worn too deeply, resulting in a nasty buzz, so I glued a thin wooden shim to the bottom of the nut.
Assembly and Set-Up.
A trial fit of everything revealed that the action would be a little too high. I enlarged the rectangular opening for the dowel stick in the rim slightly. This lets the neck move up and down relative to the rim. I also elongated the hole in the rim where the dowel stick ends. This allows the neck/rim angle to vary slightly. These two minor modifications give the action some adjustability without altering the basic integrity of the rim-neck structure.
As you recall, way back in the flange section, I talked about realigning the flange on the rim. This moved the flange forward (toward the peghead). The neck then hit the flange before the rim, so I had to remove a little wood from the heel. This was done with an ordinary razor saw. I used the sanding drum on the rotary tool for final shaping and fitting. The photo below also shows the new heel plate I made.
With several trial fits and fiddling with the neck angle and neck height, I got a good, solid neck-rim joint with the action at the 12th fret set at about 3/16".
Finally, I put on a new set of GHS bronze-wound light gauge strings. The banjo is hefty, weighing in at 7.0 lbs. Here it is, ready to go:
After all this work, it sold on eBay (August 9, 2003) for a lousy $80! The good part is that I learned a lot on this project.
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