Quote:
Originally Posted by sandmanred
This one has never had anything in it. I have the stuff I need on the way to purge so I might as well. Just didn't think it was necessary with aluminum.
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Hi Jeff, It could be argued that it isn't necessary as it's easy enough to make a tight tank without purging but as these are welds you can't get onto from behind once the job is done I see no sense in allowing the back side to burn away in an oxygen rich environment potentially causing problems that can be avoided, especially with aluminium because it likes to absorb all sorts of nasties when hot and you get more complete penetration with a back-purged weld so no leaks to chase out. I would normally spot the parts together then close the seams with making tape then purge gently as I weld, removing the tape as I go and wiping down with isopropanol to remove any residue. I stuff a wad of paper towel into the filler with the hose through the middle.
Will