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dmccarver1
11-06-2008, 08:07
This is what is looks like: 100-3AA 2250 (thats the top line). Can anyone help interpret this? The tanks have been painted in the past, so the other markings are hard to read. Its also smaller than my AL80's. Thanks.

monant
11-06-2008, 08:40
I went to this link, Tank Markings identified, what do they are all mean? (http://www.underwaterdivingequipment.com/tank-markings.html), but it still doesn't fully explain your tank's markings. How old is it?

I believe it is a steel tank with a working pressure of 2250 PSI. Not sure what the 100 means, maybe it is for cubic feet.

To ensure it is a steel tank, see if a magnet sticks to it.

TommyB
11-06-2008, 08:47
LP steel tank. Might be a LP 72 ??
DOT 3AA 2250 is a marking for steel tanks
pressure rating = 65 cft at 2250 (or 72cf)

Just a guess though :)

Prolly a US divers steel LP 72 with a first hydro around 69 or 70 making it a vintage tank

in_cavediver
11-06-2008, 18:46
Its steel with the working pressure of 2250psi.

Not sure about the 100 though. Best bet is to call a hydro shop.

captain
11-06-2008, 21:23
I think you are misreading 100 for ICC which is the Interstate Commerce Commission which was the for runner to DOT. It is more than likely a steel 72 from the 1950's or 1960's. I don't recall exactly when the DOT stamp replaced the ICC but it was around 1967.
I have a couple of tanks stamped ICC both are from the 50's, All the others are from the 70's and are stamped DOT

Bluemax
07-04-2010, 09:26
3AA is the type steel the tank is made of. 3AA is the older type steel, thicker little softer. 3A is the new steel, thinner harder. 3AA steel tanks are great. Burned three 72's yesterday. Had a great time!!!

chilly willy
07-04-2010, 10:35
Definitely a low pressure steel, great tank.

Jack Hammer
07-04-2010, 12:31
I'm sure the OP is thankful for the contributions, even if they are a little over a year and a half after he asked...:smiley2:

vegas911diver
07-04-2010, 13:11
I'm sure the OP is thankful for the contributions, even if they are a little over a year and a half after he asked...:smiley2:

LOL YEP! At least the old posts still are being read.

chilly willy
07-04-2010, 19:08
Aw s**t, I normally look at the OP date.:smiley9:

captain
07-06-2010, 09:18
3AA is the type steel the tank is made of. 3AA is the older type steel, thicker little softer. 3A is the new steel, thinner harder. 3AA steel tanks are great. Burned three 72's yesterday. Had a great time!!!

You have it backwards. 3AA is is 4130 chrome molybdeumn high strength steel. The steel race car and aircraft frames are built from.
3A is lower strength 1020 plain carbon steel found in older low pressure tanks of less than 2015 psi.

Mictrik
08-25-2010, 03:30
I think that 3A is Carbon Steel and 3AA is Chromoly Steel a lighter stronger alloy.