Alternative to filling propane tank with water ?

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mayberrysmoke

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Original poster
Dec 19, 2024
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1
I've seen a guy hookup a shop vac to one bung hole on a take on blower setting to push out any vapor in the tank before cutting. Is this a viable/safe option compared to filling with water? I don't think HOA or wife would be happy about me dumping the mercaptan water in lawn, not sure how long smell would linger and also just a lot of water depending on tank size.

Also, how do you clean out leftover mercaptan residue in tank?

Thanks!
John
 
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I've seen a guy hookup a shop vac to one bung hole on a take on blower setting to push out any vapor in the tank before cutting. Is this a viable/safe option compared to filling with water? I don't think HOA or wife would be happy about me dumping the mercaptan water in lawn, not sure how long smell would linger and also just a lot of water depending on tank size.

Also, how do you clean out leftover mercaptan residue in tank?

Thanks!
John
You should be able to pump Co2 in it to make any propane inert. Do your homework to be safe.
 
Just remove the valve and leave the tank open awhile. Any propane left will evaporate.
 
If you have an air compressor do what DougE DougE posted then push your hose down to the bottom and blast as much air as you can into it to displace any gas.
 
A radiator shop owner I use to know would run exhaust fumes into gas tanks while he welded them up if he had to patch a leak. I ain't that brave but he died at a very old age and it wasn't by blowing up :emoji_laughing:
 
A radiator shop owner I use to know would run exhaust fumes into gas tanks while he welded them up if he had to patch a leak. I ain't that brave but he died at a very old age and it wasn't by blowing up :emoji_laughing:
Gasoline evaporates very quickly so if you leave the tank sit awhile with an opening for the fumes to gas out, there is really no danger.
 
Propane will lay in the bottom and might take quite awhile to leach out of the tank, propane is heavier than air.
 
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A radiator shop owner I use to know would run exhaust fumes into gas tanks while he welded them up if he had to patch a leak. I ain't that brave but he died at a very old age and it wasn't by blowing up :emoji_laughing:
Have seen this done as well! Was on a diesel tank but same concept.

Ryan
 
M mayberrysmoke , I've always had the luxury of leaving them for an extended time (sometimes years...) with all the bungs and fittings removed but have still filled them with water and a good dose of Dawn dish washing liquid and let them soak for a week or two before cutting them. I've never had an issue with the smell.

So, I can't speak to cutting into a tank newly removed from service but if it has sat for a while with the fittings removed you should be fine.

Where are you?
 
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M mayberrysmoke , I've always had the luxury of leaving them for an extended time (sometimes years...) with all the bungs and fittings removed but have still filled them with water and a good dose of Dawn dish washing liquid and let them soak for a week or two before cutting them. I've never had an issue with the smell.

So, I can't speak to cutting into a tank newly removed from service but if it has sat for a while with the fitting removed you should be fine.

Where are you?
SE WI. I'd be looking to do either 80 or 120 for first smoker. Maybe am better off finding an air compressor.
 
Propane will lay in the bottom and might take quite awhile to leach out of the tank, propane is heavier than air.

Just turn the tank upside down.

SE WI. I'd be looking to do either 80 or 120 for first smoker. Maybe am better off finding an air compressor.

After seeing "Mayberry" in your forum name I asked about your location as we live in the land of Andy Griffith in Pinnacle, NC. We're four miles from Pilot Mountain (AKA: Mount Pilot) and a few more miles from Mount Airy, NC, (AKA: Mayberry). If you'd have been local I'd have been glad to help you cut your tank. Heck, I have some well vented and ready-to-cut tanks in the woodline awaiting conversion and you could have had one of them.

Personally, I'd make sure a propane tank is vented and empty of pressurized propane before picking it up and after bringing it home I'd dump in a big bottle of Dawn, fill it up and wait a few weeks.

A stiff dose of Dawn dish washing detergent in the tank left to sit for a few weeks will tame the ethyl mercaptan so don't worry too much about that.

For what it's worth, a lot of knowledgeable folks think that 24" diameter is about the smallest that fits a truly useful second rack. It's also worth noting that air compressor tanks trend a good bit thinner than propane tanks so they may be a bit harder to hold steady temperatures in, particularly on cold or windy days. I know that propane tanks are hard to come by in some areas and we have to use what we can get but before choosing a compressor tank I'd hold out for a propane tank if possible.

A lot of vertical 120 gallon tanks (typically 4'6" tall and 30" in diameter) have been made into top notch smokers but my personal preference would be to try to find a horizontal 120 gallon tank (typically 5'8" long and 24" in diameter). That will be harder to find but, to my mind, it's a better shape for a mid size horizontal smoker than an upright 120 gallon tank .

If you have anyone around you specializing in converting trucks to LP gas you might get a deal there on a tank removed from a big truck. I have one awaiting it's rebirth that's around 23" in diameter and 6" long that's about 3/8" thick that came off a retired concrete mixer truck. I haven't yet decided whether it's going to be a trailer mounted smoker or get whacked in half to make a pair of patio size smokers with warming boxes.
 
So I made a video back in the summer of me cutting a propane tank with a plasma cutter, using less water, not filling it all the way up, putting it up on end. Maybe this will help someone.

Mercaptan smell in the lawn isn't a big deal, not going to stick around in open air after being mixed in water and Dawn dish soap.

This was my first real attempt at editing video, so I hope it isn't too annoying. I'm not a tech genius.

 

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As mentioned above but not together - flip it upside down and then dump your biggest air compressor into it, wait a day and have at it.

The explosive range for propane in air is around 3%, and propane is heavier than air - just letting it air out or flushing upright can lead to a situation where you went past a "safe" fireball that will require new pants and into a ddt that will require very good health insurance before the last bit is gone.
 
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