Sousaphone Repair

[Rick Denney]

Bondo?

Not recommended. Bondo uses a polyester resin filler that is neither waterproof nor strong. It works because it it applied in a very thin skin over metal--thin enough to remain flexible--and then it is painted. I have used it for filler that is loaded only in compression. such as for patching holes in floors, but not for skin structures that are loaded in bending.

The epoxy that Joe mentions should work fine, but so will any good waterproof epoxy, such as the West System materials made for boat-building. The different mixes and hardeners are to control the set time, so get the slow-setting stuff and don't worry about it.

Rick "who has a fiberglass project in the works" Denney

[imperialbari]

When the cohesion has been compromised, then a repair will be followed by a new crack. That appears to be the lesson of this thread.

One way to go would be the Jupiter-emulation and put on one of the brass bell floating around after loosing a working body.

If such brass bell has its own problems like a compromised or non-fitting collar, it still may be of help. At least in my imagination, as I haven’t ever had a fiber bell in my hands. What about cutting a broad garland out of the brass bell and glue it to the back of the fiber bell? The same brass bell might even help more than one fiber bell as the garland doesn’t necessarily have to sit along the bell rim.

Klaus

[ken k]

white duct tape???
isn't that in every handyman's tool kit?
k

[windshieldbug]

white duct tape???
isn't that in every handyman's tool kit?

No, that's silver Duck Tape

[J.c. Sherman]

God I hate these repairs!

First, if you have a King or Jupiter, buy a new Jupiter Bell. You can get a good bell and the Jupiter fits the King, and the cost is minimal and it looks and lasts good/well.

Second - I'm going to try a different technique next time - using sheet metal (brass?) over the crack as part of the fiberglass and resin application. Try to make it stronger at the crack, with room enough in the crack for the epoxy to set against itself through the crack. Probably won't work, but I'll try anything.

Beware the Plastic bells vs. Fiberglass! Nothing fixes them, ever!

Third, eBay can also be your friend!

Replacing a chip from a Sousa bell is a heck of a lot easier to fix than a crack or large broken section. Sometimes it can work quite well!

As always... your mileage may vary...

J.c.S. (who wonders if anyone else is having weird scrolling issues in the message field!)

[Rick Denney]

Beware the Plastic bells vs. Fiberglass! Nothing fixes them, ever!

With plastic such as ABS, you can use ABS cement and cement a patch. ABS cement is a solvent weld and as durable as anything.

Likewise PVC, but I'll bet they aren't PVC.

Polypropylene and polethylene can't be glued successfully because nothing sticks to them. But they can be welded if you have some filler material made of the same stuff. A big soldering iron will work as will a plastic welder that uses a low-pressure stream of very hot air. As with welding metal, the key to strength is complete penetration.

Any thermoplastic can be welded with heat. But resin-set plastics like some acrylics, epoxy and polyester fiberglass fillers are thermosets, and can't be softened with heat successfully.

Rick "who bets those non-fiber-reinforced bells are ABS because it's cheap and easy to vacuform" Denney