Small home made reusable refrigerant tank

Well a good number of us use old green propane tanks as a container for scavenged refrigerant or to recover into, but to do so we have all ways have had to mod a torch head or messily braze in a schrader. Most of thees solutions have left much to be desired and all have perspective reliability issues.

After trying to figure out a better method it struck me, why not use a can tap for it? So I set out and checked the threads as luck would have it I found the exact tap needed, so off to try it out!

First thing you will need:

- 1/2" UNF tapered thread tap.
- a 27/64th Drill and a 29/64th Drill bit.
- Access to or have a drill press with a cross vice preferably.
- A thread sealing compound rated for gas use at the temperatures it will be exposed to.
- A can tap (You can get them from frosty freeze cheap)

Get an old EMPTY propane bottle and use a valve core remover tool to take the schrader out of it, then blow some low pressure air through it for several minutes to purge out any remaining gases. Cut off the thread leaving as much of the stem as possible.

Drill the hole out first with 27/64th drill taking it slow and steady, then ream out further with the 29/64th bit ensuring a slow smooth bor hole.

Dip the taper tap in oil and cut a 1/2UNF thread, take your time to ensure it is aligned right and straight, you want a good quality thread!

Once the thread is cut wash the inside of the cylinder with methyl alcohol (IT IS TOXIC & FLAMMABLE so don't touch it if you don't know how to use it safely) and then dump out and dry the inside of the cylinder.

After drying out and cleaning the cylinder take your can tap valve & remove the pin and O-ring off of it. Clean the threads with a good quality degreasing agent and test fit to the propane tank to ensure a smooth tight thread and fit.

Allow all parts to throughly dry and then apply thread sealing compound to the upper half of the threads and bold on tightly and then torque it a bit to ensure the thread is 100% engaged and the sealing compound has effectively coated all the thread gaps.

Allow sealing compound to cure for the night and half of the day (24Houres) then vacuum out the bottle to the usual 500 Microns or better for minutes or so, then break vacuum with N2 or refrigerant. Pressure test it for the day to ensure it is adequately sealed.

The burst valve in a propane bottle is set from 250 to 300PSI I have yet to actually see it go when recovering R-22 into one so it must be the upper 300 range.

SPECIAL NOTE: Do not forget to relabel the bottle and or repaint it to match the refrigerant inside and never put any refrigerant that will exceed 300PSI at 40C(105F) into it.

thats good! what is the point though? sorry im new to phase

The point is that it is a much more reliable method of storing home recovered refrigerant from small systems that we are modding as the valve is rated for refrigerant usage and is much more durable then a modded torch head. For thoughs who are limited to using air duster as refrigerant they can now make an easy re-usable cylinder to store it in when they mod their system as well.

How much time did this take you (excluding the time waiting for pressure etc), Xeon? I think you could amass a small fortune selling these things to noobs, if you were so inclined! ;)

Ah legalities though, can't sell this sort of stuff. It took less then 30minutes to do the purging, drilling, tapping, cleaning, it is the curing time of the sealing compound that takes the time 24H then rest is fairly quick.

Nice job! I love those little green tanks.

That's really too bad, but I can understand the legal constrictions. Really, the hardest part of the process is acquiring the tools, like the drill press and tapper. Assuming I can find them, I've give this a go over the summer, and save some money on a recovery tank!

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Originally Posted by Starkiller42

How much time did this take you (excluding the time waiting for pressure etc), Xeon? I think you could amass a small fortune selling these things to noobs, if you were so inclined! ;)

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Even though I'm sure they would hold up to their rated pressure beautifully, I wouldn’t sell a modified non-refillable LPG cylinder for any uses other then its sole intent. It looks like a great little tank, and I may make one in the future for my self, but I would haste on selling due to liability issues.
Lets say someone filled it with a higher pressure gas and the safety popped and hit that person in the face, the liability would come back on the person that changed the tanks functionality. and I really don’t want to sound like I’m wineing but in the EPA section 608 certification litiature, I read that one of the main reasons that non-refillable cylinders are illegal to refill is because:
say the tank was left open for a long period of time, or it got water in it somehow. The integrity of the cylinder walls would be compromised, thus the cylinder "could" fail under pressure before the safety had a chance to relive the pressure. That really only applies to the carelessness of people that would leave this thing sitting for a few years in a humid area, but they are out there...

Still I like the idea, who makes that valve?

Aye, I realized the folly of my ways shortly after posting. The irony is that the biggest market for these things would likely be the relatively inexperienced builder, whom only intends to make a couple units, and whom therefore is most likely to screw up with this thing.

Let's just call it a brain fart and leave it at that ;) .

Technical Chemical Co. "Professional Dispensing Valve"

I get them from frosty freeze and their dirt cheap, the mode to the valve is super easy the Oring can be pulled out if you have finger nails and the pin a good pair of pliers and a strong grip it slides out.

http://cgi.ebay.ca/R-12-Pro-Dispensi...QQcmdZViewItem < This is a great starter kit

http://cgi.ebay.ca/R-12-Professional...QQcmdZViewItem < For thoughs who all ready have tons of hoses.

For the newbs that attempt this project is why I was so specific as to the limits of it and what would be a safe pressur / temp range.

A modern recovery machine will pump up to 525 to 550 psi high limit, recovery tanks are 350psi normal or 400 psi for R410a and they are much thicker than propane tanks.

exactly this is NO substitute for a proper recovery system, this is simply a stop gap to allow recovery of low pressure refrigerants such as R-290, R-22, R-134a, and such.

I do like where you are going Xeon. I think you should have installed a T though with a pressure relief. Possibly a pressure cutoff that plugs into your home made recovery. I like that your looking to help the environmental problems that XS does produce in small quantitys.

Not DOT approved and way aginst the law as far as EPA regulations! (sect - 608)

big $$$$ fines involved, so id say watch out for the men in suits,


very nice $ saver if every thing works out :)

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Originally Posted by V2-V3

Not DOT approved and way aginst the law as far as EPA regulations! (sect - 608)

big $$$$ fines involved, so id say watch out for the men in suits,


very nice $ saver if every thing works out :)

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You do realize the irony in this statement? Albeit true it is all so true be making these units AT ALL is a violation of the law in of its self. So in the end any thing goes. BTY DOT is just for transportation, just don't take them any where ;)

DOT says you cant transport them, EPA (THE FEDERAL GOVERNMENT) says you cant use them. it is a huge violation that they will fine/jail you for. the EPA has really stepped it up on section 608 violations (refrigerants)


making these units is not a violation of any law unless you posses refrigerants and do not have an EPA 608 license to handle refrigerants. not sure about how many people on the forums do or do not have their certs. I doubt any one would actually be pwnt by the EPA unless they posted pics of them dumping 4000LBS of R12 into the air :D
A good rule of thumb: if they wont let you buy it with out a license its illegal for you to handle it.
(if you want to stay legal) you do not need a license for some very useful refrigerants here are a few off the top of my head. most of them can be purchased from places that have alternative uses.

R290
R600a
R600
R744
R50
R702
R704
R717
R718
R720
R728
R732
R1270
R170

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Originally Posted by V2-V3

making these units is not a violation of any law. :D

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Yes it is every unit must be certified by epa and dated, older units before 1993 iirc get a gradfather clause and only need to evacuate to 10hg vacuum.

New units need to be pulled down to a 300 Micron Vacuum
and must have UL equipment or its your neck when anything bad happens

I could be wrong, so im going to look at the 608 codes again. :P

Unless you have your system commissioned it IS illegal.

V2-V3: throw up R410A on that list :D .

now to use this all i need is the tank and my manafold right because it is low psi's

Why not just use a empty refrigerent tank? I have about 10 of them I was going to use them for an onboard air setup for my truck. I think I can spare 1 or 2 for recovering.

sure but one thing where do you live because i live in canada

Quote:

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Originally Posted by Starkiller42

That's really too bad, but I can understand the legal constrictions. Really, the hardest part of the process is acquiring the tools, like the drill press and tapper. Assuming I can find them, I've give this a go over the summer, and save some money on a recovery tank!

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you can drill ith hand drill and tap with tap and tap holder wrench, but remember you must only fill to 80% and do not put high pressure gas in them. recovery machines can pump to 525 or 550 psi and that may bepast rupture point. best to spend 60 to80 dollars and buy a recovery tank that is dot approved and 410a models can have 400psi in them.

nevery fill any tank over 80% by volume, not all gases weight the same as water,which you scale is calibrated by. water has a denisty of 1 and air has a density of 1 in imperial system of measurement.

http://www.r22.org/prod_list.php?mai...Recovery-Tanks
$80 delivered ;)