Sunday, February 6, 2011

Adventures in Fiberglass Sousa Repair: Bell breaks

above: a Conn 36K bell with a chunk missing from the bell flare
I have seen Sousa bells hit the trash heap because of damage like this. It is true that this example isn't severe, it just happened to be the one I was working on. It is possible to give new life to bells missing material. The repair for this isn't the same every time. It changes depending the severity of the damage and the particular horn I am working on. Here is how I did it this time.
The first step I took was to use a dremel cut off wheel to cut channels into the flare. This is so I can lay down steel wire to add strength to the graft I will create later. A picture of the wire is below.
Next, I use epoxy putty to create the missing material. I form it on the bell and shape with a razor as it sets up. Due to the width of this missing material, the putty developed cracks because of the flex in the bell flare material. Because of this, I used an additional layer of bondo fiberglass strips to give strength to the new piece. The blue marker lines mark the small breaks in the original piece. They can be seen under the bondo patch.

After the bondo patch sets up, I sand down the high spots as much as I can to attempt to blend in the repair. I cannot make it perfect or completely disappear. This is because I don't want to lose the strength of the patch. Truth be told, I could have went further with the repair and made it look better, but for time reasons, I decided to stop.

Below are pictures of the bell after repainting it. Up close you can see the high spots from the fiber repair. It isn't perfect, but it is durable.

 The final product looks pretty good. What do you think? Let me know!


  1. I have a crack in the bell of my fiberglass Conn. It's only about 6 inches long right now, from the outer rim of the bell going inwards. How would you recommend I repair something like this?

  2. Still up for repair suggestions if the blog is still active!

  3. use fiberglass epoxy with cat hair glass making sure to get it into the crack sand smooth with fine grit sand paper 300 grit prime and spray your good to go

  4. Thanks for sharing wonderful information with us. Really Like the information.
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