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Originally Posted by dolphinboy400  correct me if i'm wrong ( which is often :P ), ANY liquid is denser than air so therefore, if it doesn't leak with an air test then it should hold any liquid ( apart from extreme tempretures like liquid nitrogen ) . I test heating systems on copper/plastic/steel at only 20 mbar but those systems can run at 3 bar, not sure what that is in old money but it's way more than 25 psi, right?
The pressures that these tanks hold are minimal and i cant see why an air test wouldn't pick it up , unless i missread something and what your saying is the fuel corrodes the weak part of the weld over time, which would be a worry for everyone  |
Aluminium welding is very critical about clean materials. When welding cylinders or sealed containers it is best to purge the inside of the tank with Argon to prevent contamination getting in the weld pool on the reverse side of the weld. obviously not possible until you have a sealed container to work with!
If there was any oils or contaminates on the opposite side of the sheet these may get into the weld pool then cool down and seal the hole. Oil or grease will melt in petrol however showing a leak.
Maybe the air test needs to be revised but testing with fuel would mean they couldn't send it by parcel delivery.
If I was Dax I would have stuck with the easier to make and cheaper option of a steel tank. Weight difference would be minimal as steel sheet can be thinner than the aluminium needed for the tanks.
I guess they have to go with what the customer demands though.
Does any other kit use aluminium tanks?
Craig.