Cool. Just had cyclic vibration stress in mind on those welds. I'm sure you you'll keep an eye on it.Hi Azwad, Thank you! Those chambers are specifically sized to target 100 to 110hz range, the low boom tone.
They are empty and not weighty, I did think about adding a support at the end of the canister, but the weld around the neck is strong so it more than supports it's own weight.