Ideas on cleaning a Mastercool 30# DOT carbon steel recovery tank?

So far, I’m not happy with what the isopropanol is washing out. Red/orange tinted with black sediment of some kind…

I feel like continuing to wash my be futile and just picks up more rust/debris. I bought it new from BVV, and it did come fully charged with what was allegedly nitrogen. It didn’t blow anything up when I discharged it to atmosphere so there’s that… At any rate, any ideas to clean this any better than alcohol rinses?

Any thoughts on mitigating this by distilling (butane cans) to an intermediate 304 ss tri-clamp holding pot at the top of every run?

I’m researching now if that will leave any kind of heavy metals and other common contaminant behind. I know it’ll clean up most other undesirable organics that would appear but not so sure about heavy metals. Will also be ordering a molecular sieve filter can to put inline on the return line for recovery.

Bonus points if anyone knows this as well: What are the dip tubes made of? Of course, after already receiving the product it dawned on me that I wasn’t sure and am curious about solvent compatibility. It would stand to reason it is compatible, but it may not be to a food-grade standard since these are for HVAC.

This is to displace the atmosphere and avoid moisture (which will lead to rust) when storing an empty tank.

Sounds like rust may already be an issue if you’re seeing

Unless it’s oils that you’re seeing.

Definitely not sanitary welds. Black flakes can be from carbide precipitation, due to not back purging the weld.

It depends…

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If you’re going to use isopropyl, it should be anhydrous, or at least 99%. I personally wouldn’t put anything other than butane (free of moisture) in a carbon steel tank.

Definitely worth investing in a stainless steel tank. A similar size non-jacketed tank is only a few hundred dollars.

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Yeah it was 99% and then I let it drain/dry overnight upside down before pulling vac to let it sit. I realized after posting that if heavy metals from the tanks were an issue it would be in the distilled butane (like when people buy 20lb bottles and distill in the CL) too so that put my mind at ease. I will distill from this recovery tank before running with it first time to see if it adds any mystery oil/crud back into the solvent after being distilled the first time.

I’m definitely eyeing an ss jacketed recovery tank that is outfitted for long-term storage as well but that will have to wait until I am employed again :expressionless: (it’s only a hobby for me to get cheap concentrates). Just didn’t want butane sitting around in a container with pretty much zero safety features and no way for me to lock up outside.

Unless you can open up the tank and take a good look inside with a camera to make sure it’s really clean and safe for continuing use, why would you ever trust that tank again?

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Necessity, for now. I’d rather store it safely without explosions and have to do extra filtering/distillation steps than to risk fire/explosion. Ultimately it came down to, this is the same state that butane tanks come in from suppliers so if distillation mitigates that, then I would imagine it mitigates this situation too. Especially since it’s a new tank I’d hope it’s only manufacturing contamination.

Do you think that’s insufficient? I only need this to last until I can afford a proper stainless tank.

Why don’t you put a “want to buy” ad here on the forum and try to get your hands on something you can trust and that will last… And more than likely more functional than what you are using

I’d say If anything red came out of your tank. It’s cooked.

You don’t wanna risk your health or someone else health for $100. You can buy another carbon steel tank brand new off Amazon if money is an issue. Otherwise you really should upgrade to stainless.

This is the reason we never sold carbon steel tanks. You run no sieve for 5-10 runs and you have enough moisture in your solvent to rust your tank. Trust me. I learnt this the hard way too.

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damn, I may need to try an RMA then. It was definitely reminiscent of rust color and they definitely sell them as new. Thank you for the caution.

I will try that. New to the forum and didn’t even think to look for a marketplace. Thank you!

it very well might have been new. but maybe over time some of the nitrogen was released which allowed part or all the tank to rust on the inside.

there is no cleaning agent that is red so there should be no tint of red in the tank. these tanks are relatively cheap and if you need to question it at all… it needs replacing.

ANY Second guessing should automatically result in changing the item. This isnt a game. Safety is the number one. Im not saying your tank is compromised but rust compromises the structural integrity of metal. We deal in pressure vessels… which can be deadly. Its $100. please make the right decision.

happy holidays

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Hope you had a good holiday! If I may pick your brain a little further… if sudden depressurization could be ruled out (im only speaking hypothetically for my edification) is there any danger from the container material itself in contaminating the solvent or would that all be left behind upon distillation?

Originally, I was going to use this only as a storage tank in between runs. I have a stainless steel welded bottom spool i use during operation to hold the solvent and recover it. I’ve since found out about the possibility of lead in the brass fittings… but I can’t seem to find anything that indicates that lead is soluble in LPG. I see a LOT of people using these tanks with their CLEs… is there just that much lead contaminated extracts out there? kind of scary if so.

Brass valve assembly on your source tank isn’t going to be an issue. That carbon steel refrigerant tank is likely trash.

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okay, that makes sense… yeah I have my recovery pot going into a regulator and bunsen burner to just burn off the solvent when I’m done. It sucks, but the system is only meant to run .7 Lbs max so it’s just the cost of a can 420-540ml of butane basically. I only need to run it about every 3-4 months as I harvest my autos.

Part of why I got the carbon steel recovery was that it has a pressure relief valve. I was worried about storing solvent just in a welded spool with a single ball valve keeping it in. Seems far too easy for someone to accidentally hit the valve lever or if it overpressures from temp or something there’s no relief valve. Even with a stainless tank I’d then have to worry about theft from my outdoor storage area. (I live in condos but I extract on a friend’s rural property)

And thanks everyone who’s shared advice and knowledge. It is much appreciated

I wrote about this once on a safety thread. I can’t help but mention it here.

Savant, don’t put too much faith in the PRDs on these units. The PRDs on the valves were not meant for use with flammable solvents. They were designed to be used with non-flammable refrigerants. Only one company lists this:

https://www.vevor.com/recovery-cylinder-c_10322/vevor-refrigerant-recovery-reclaim-30lb-cylinder-tank-with-floating-switch-p_010977352965

LPGs should have spring loaded PRD’s that release vapor from the container if the pressure gets too high.

The valves on these refrigerant recovery tanks might be compatible with hydrocarbons and other flammable solvents, but who knows for sure. They have burst disks that rupture and immediately release all contents, vapor & liquid. Fires are bad, but explosions / bleves are far worse.

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You can install your own PRV on a stainless tank, or any spool/vessel.

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You should really have PRV’s at all isolated locations on your system. CRV’s (Cryogenic Relief Valves) would be even better.

Generant is a good brand, they make cheaper ones in brass as well.

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If this is your 45g extractor, you should upgrade to high pressure clamps as well. I honestly can’t believe they’re still selling systems like this.

When making future purchases, I’d suggest going larger. It’s better to have the capacity and not need it, than to need it and not have it. You can always run that smaller amount in a larger extractor and not have to worry about over recovering with a tiny spool.

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That’s the one. You actually saved me a future post. I was going to ask about what people thought would be a good upgrade other than a recovery tank. I’m seeing that there is a lot of exploitation in this gray area seemingly aimed at home growers and hobbyists. I’ve noted the sizing tip. Now, I assume you mean replacing the clamps with the high pressure brass bolt kind? I’ve been reading that… would you say it’s an immediate danger and I should not operate until replaced or is it because these wear quicker only having those pins carry most of the load? I see they are typically rated 250-300 psi operation… not enough overhead?

Any other recommended vendors? I noticed the marketplace here too. I started with BVV simply because I had bought a vac chamber from them and noticed they did this other shit.

FWIW, I do pressure (100psi compressed air) and vac test it overnight before every day I’m going to run it and I do a quick 10 min one anytime I disassemble anything more than a JIC hose during runs like if I recharge the material column. In the three runs I’ve done so far I’ve always topped out at around 40psi in between the collection and recovery phases. I use dry ice on the solvent container and the material spool (little DIY jacket).

Sorry If I’m long winded… I’m full of questions as a newb.

Oh wow… thank you very much for that. I hadn’t come across that in my research. Between this and other concerns I’ve definitely benched the carbon steel tank. It’s a lesson learned in an expensive paper weight lol.

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