Automotive Air Conditioning Information Forum (Archives)

James89dx on Mon January 12, 2015 2:04 PM

Year: 1989
Make: Honda
Model: Civic
Refrigerant Type: R12

Does anybody know definitively what the weight of an old DuPont 30 lb r12 tank is? I don't have a picture of my tank offhand but it's identical to this listing I found on ebay:

DuPont r12 ebay listing

I bought the cylinder about a year ago just intending to get enough out of it to do my Civic (~ 30 oz) when I overhauled the ac system. I finally got around to that this weekend and am trying to figure out how much r12 I have left in the tank now after doing my car. I figure if I know for sure the weight of the tank itself I can deduce how much r12 is left.

Thanks

HECAT on Mon January 12, 2015 2:36 PM

DOT 39 jugs (one way-disposable) that hold 30 lbs. of refrigerant; will weight 7-9 lbs. empty, depending on the manufacturer.

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emsvitil on Mon January 12, 2015 8:17 PM

Not dupont, but my empty 30lb R12 cylinder weighs 5.010 lbs according to my digital scale (max 11lbs)

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Ed
SoCal

James89dx on Mon January 12, 2015 8:53 PM

Hmm well I got home from work and weighed mine and it's weighing in at exactly 7.03 pounds. I can feel it's got a decent amount of r12 in it (I can kind of "feel" its density move around), but I just wish I knew for sure how much.

If the empty tank weighs 5 pounds that would be ideal because that means I'd have just enough r12 left over to do another Civic should I ever need to.

Using the 30lb tank is exponentially easier than the little cans (of which I have about 20) because charging by weight takes all the guesswork out of it. Last time I did this car a few years back I charged it with the cans and was never quite confident the charge volume was totally correct.

Anyway, thanks for the replies. Hopefully somebody sees this who has (or could find) this exact tank and could post the exact weight.

HECAT on Tue January 13, 2015 3:07 PM

Quote
Originally posted by: James89dx
Hopefully somebody sees this who has (or could find) this exact tank and could post the exact weight.

There are about 2500 registered DOT cylinder manufacturers globally (not all make DOT 39). There should be a Mxxxx number on the collar that might help identify the manufacturer, who could then be contacted for the empty tare weight info.

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emsvitil on Tue January 13, 2015 6:56 PM

ok, my 5.010 lb tank has

DOT-39 NRC 260/325 M 1079

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Ed
SoCal

James89dx on Tue January 13, 2015 8:38 PM

Hmm mine is DOT-39 NRC 260/325 M 1005

I did some Google searching and found lots of guys trying to repurpose these tanks but no tare weights listed. Also even found a thread from this very forum about a guy who called DuPont directly and even they couldnt tell him with any certainty. So I may be SOL

mk378 on Tue January 13, 2015 9:31 PM

It is likely that DuPont subcontracted or licensed the filling and distribution of the 30 lb tanks. It doesn't make sense for a huge chemical plant to package and sell product in retail quantities, they just ship it out in tanker quantities to someone else. The subcontractor would have bought empty tanks from various sources.

Edited: Tue January 13, 2015 at 9:35 PM by mk378

HECAT on Wed January 14, 2015 7:16 AM

Both M1079 and M1005 belong to two different US manufacturing locations of Worthington Cylinders a.k.a. Worthington Industries. I would contact them for a definitive answer.

Or, since same manufacturer verified, go with emsvitil's provided figure of 5.1 lb.

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emsvitil on Wed January 14, 2015 7:51 AM

5.010lb

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Ed
SoCal

James89dx on Wed January 14, 2015 12:26 PM

Well I contacted Worthington and was told they "don't have tare weight on our drawings or brochure" and then they e-mailed me a copy of their brochure which, just like they said, does not have tare weight listed. I don't think they're too eager to figure this out for me lol.

I found a guy on eBay selling an empty orange Helium tank with the exact DOT-39 NRC 260/325 M 1005 number as mine and messaged him and he said his empty tank weighs 8 lbs and 6 oz. Obviously that can't be the same tank as mine.

I guess I will just go with an optimistic 5.010lb tare weight. Same manufacturer verified thanks to HECAT really makes me pretty confident. This means I should have 32.48 oz of r12 in my tank - enough for one more Civic charge should I need it in the future

Thanks guys

James89dx on Wed January 14, 2015 12:52 PM

Well the rep at Worthington must have felt bad for me. She just e-mailed me back and said she did some more checking for me and that the tare weight is 5.2 lbs

5.010 lbs vs 5.2 lbs, either way I've got right about 30 oz left which is just enough I was hoping for