Luxfer S67 tank alloy

[guruboy]

i have a Luxfer S67 3AL tank made 86

8" Dia and about 20" tall

Does anyone know if this is 6351 alloy? This model doesn't show up in the published list.

 

[runsongas]

you have to call luxfer to confirm, but chances are good it is 6351 as the changeover didn't start till 87.

 

[guruboy]

you have to call luxfer to confirm, but chances are good it is 6351 as the changeover didn't start till 87.

except it's not in their list

 

[snowdog61]

yeah - odd....no S67 in the listings I have. Looks like you'll need a VE stamp and a knowledgeable fill station as it's likely the 6351 alloy. Sadly more trouble than it's worth IMHO since I'll venture it's just fine

 

[Charles2]

This quote is from Luxfer Dates when Luxfer changed its aluminum alloy from 6351 to 6061 : "Between 1987 and 1988, Luxfer Gas Cylinders discontinued use of 6351 aluminum alloy and began using a proprietary version of 6061 aluminum alloy for all its aluminum cylinder models manufactured in the United States. Listed below are the dates by model number when the transitions to the new alloy occurred. Any current Luxfer models that do not appear on this list were never made from 6351 alloy in the first place and have always been made from Luxfer's proprietary 6061 alloy."

Sounds like you are safe, although there still may be some shops that will not fill. Also, I am not sure of this statement, but I was under the impression that cylinders stamped as conforming to 3AL specification were 6061 alloy. I could be wrong.

 

[runsongas]

the s67 is not a current model

 

[runsongas]

except it's not in their list

it was discontinued by the time the list was released i believe, that is why it was omitted

 

[guruboy]

@Charles2 good catch. I missed that part you emphasized.

 

[Charles2]

Also, I think that all cylinders manufactured to the DOT-3AL specification (such as the one pictured) will be of the 6061 alloy. It is my understanding that the use of the 6351 alloy was identified by the specifications DOT-SP6498, DOT-E6498, DOT-E7042, DOT-E8107, DOT-E8364, and DOT-E8422.

 

[runsongas]

https://www.phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/3al_advisory.pdf

Includes 3al tanks prior to 1990. 3al spec was amended to prohibit new 6351 tanks but there were some 3al tanks made with 6351 by Walter Kidde and luxfer