Word of Warning on Thumpers

[SmokyMtn]

I've been actively stilling for a few years now. But only recently experienced the enjoyment of running a thumper. My recently built all copper still included a thumper made from 20 oz copper sheeting. The top has a 4 inch fill port and the obvious in and out for vapor. Completely flat across the top.

During my cleaning runs yesterday I was quite surprised by how loud the top sheet of copper was sounding off. With its name "thumper" I expected some light bubbling sounds. Maybe something so soft you would have to put your ear close to even pick up. WRONG! Think sticks and metal trash can, given to a drummer.

I only share this for people planning on building, and have neighbors nearby. Building out of thinner gauge copper sheets is not going to be stealthy. Luckily I live in a remote area.

Thumper sound and audible detection isn't mentioned much here. When you're planning a build, think of nosy Nancy next door.

[S-Cackalacky]

Don't know how you have the end of your input tube vented, but that can contribute to the noise level. Try a few holes near the end. The sound is created by the collapse of the hot vapor entering the cold thumper liquid and suddenly condensing. By the time you start producing output at the takeoff, it should have quietened down. You can also make it a little quieter by starting off at a lower heat rate in the boiler until the thumper reaches a good level of heat.

[SmokyMtn]

Unless there's a performance issue later, I'm probably not going to mess with it. The 4" fill port limits access, definitely not desoldering. Maybe dremel and a cutoff wheel, cut slots.

The tube is just cut at 90°, a v notch or holes would have helped. I honestly didn't think about at the time.

[Twisted Brick]

Welcome to the club, SmokyMtn. When I first tested my keg thumper in the backyard I was wary what the neighbors might think but got over it and the clatter soon subsided. Some insulation might help reduce the volume of your 'thumpin' copper kettle drum'.