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Old 10-20-2015, 08:48 PM
crystallographic crystallographic is offline
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Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
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Default Dirty fuel gas -what to do? (sticky?)

I thought I would post this because of a long-standing problem with dirty gas from fuel-gas suppliers that does not seem to be going away.

Dirty fuel gas on aluminum is very evident, but is also seen on steel. Hydrogen does not seem to suffer from dirt as much as acetylene, although propane, propylene, chemolene, and etc also suffer from dirt, contamination, impurities.

If your aluminum gas weld is rough, bumpy or wrinkly, this can be caused by contaminated fuel gas. Just like water and dirt can be found in gasoline, so also are contaminants found in fuel gases. For many decades the gas has been delivered in a very clean state, but this seems to be changing.

One solution is to ask for a "re-purified" bottle of gas, if available. And this is about double the price.

The second solution is to add a filter, like this ($135. or so):
http://www.perkinelmer.com/catalog/product/id/n9301399
Available for atomic absorption processes, the filter element is easily replaceable, and the flow rate is very adequate for welding.

Looks like this next to a gasaver:
acet filter.jpg

The fuel gas comes out clean and your welds show the improvement in quality.

I had some weld samples around here for the last class series .... have to dig them up and photo them to show dirty aluminum welds vs clean.

Hope this helps,
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Kent

http://www.tinmantech.com

"All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919.
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