Welding end caps on a Aluminum pipe?

by Kevin
(Florida)

How would i weld end caps on a aluminum pipe? The pipe needs to be completely sealed. Everytime I get down to the last spot to weld, the weld will not take and is pushed out by the pressure inside. Any recommendations?

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this is where threaded plugs come in handy so that you can leave a vent hole and then screw in a plug with teflon tape when you are done welding.

either that, or leave a small hole and wait till it cools and hit it quick.

or......heat the piss out of the whole thing before welding the last little bit.

threaded plug sounding pretty good huh?