How to Repair a Gong
By Kent White
Click on each image for a larger view. See our TM Technologies Air Power Hammers.
This gong is 6ft in diameter, is made of bronze, and was rescued from some artist trying to re-work a water feature into it. The new owner sent it to me asking if I could take the dish-shaped depression out of the center of it and make it back into a nice-looking gong.
The straightedge shows how deep the dish is and a bit of the rough surface. This thing is .100" thick and is really hard.
"Rough" is a gentle description of this piece.
Yes, the gong was made of 3 pieces and welded together. I spent some time figuring how bad it would oil can and if the welds would come apart. It did and they did and I still won the match.
I keep a nice weed burner handy, along with a stout supply of "propain." Heating bronze to a dull red in the dark does not look the same to the camera, but after a water quench the proper softness was achieved. Yes, that flame does look three feet long and it does sound like a dragon with garlic-grapefruit heartburn.
I set up my Air Power Hammer with the Super Thumper air unit, and had a go at shrinking the dish down. The heat-affected area is visible in the center of the gong, along with the wrinkles left from shrinking. The old arms got heavy after an hour of this clattering so I had to find a solution for that.
Handling a 100lb chunk of bronze seemed like a good Tom Sawyer moment, so I enlisted a helper and wore his arms out - but we got the surface worked well - after ringing some long sustained notes for the neighbors.
Several types of compounds were employed to bring up the finish without sanding. I like the 9" wool bonnet for heavy work, especially when cranked by a good air motor.
The surface seemed an improvement over the original. I added the "Eastern percussion look" to the center because I could not planish out the ferocious hammer marks left by the "dish-maker" and so "camouflage" seemed the best ticket out.
This little image was sent to me by the company I did the job for. They made a nice circular saw blade rack for the gong that probably also keeps unclothed people back a safe distance.
Kent
