A Small Confession

[jabbo]

Okay, I spent 13.5 years in the Army and have seen and done many things.  These days, only 3 things make me nervous, not including my mother-in-law.  Electricity, car batteries, and flammable gasses.  I can usually muster up the stuff to work with them, but I must say, I would rather be back in Afghanistan taking incoming fire.  Of those three, the gasses scare me the most because I have used them the least.  It's funny I was a combat engineer and have no problem with C-4, but I get as nervous as a long tail cat in room full of rocking chairs around a propane tank.  If you guys can manage to stop laughing long enough, I would greatly appreciate some info on the safest way to evacuate and cut into my future TBS maker.  Feel free to get it all out of your system first!!!  

  

 

[jarjarchef]

Thank you for your service.Lots of info on the site in cutting tanks. I am not an expert by any means, hopefully some of the metal working experts chime in. Below is just a couple things I have seen.My brother in-law used to work on gas stations and when he and I were discussing the cutting of propane tanks he told me how they cut fuel tanks in the field. They did not have the time to soak and rinse out. They would put dry ice in the tanks and let them sit for a short while so the CO2 would push the O2 out of the tank.What I have seen most on SMF is people filling the tanks with water, then draining and refilling with water some Dawn Dish Soap. Partially draining the tank and then cutting.I have also seen where they do the water filling and while they are cutting the tank they have a blower or air hose pushing air into the tank as they cut it.But I agree. The thought of blowing myself or others up with compressed gas freaks me out a bit too...

 

[jabbo]

Thanks Jarjarchef.  The method I have found that makes me feel the most secure, thus far, is filling once with water, filling again with water and dish soap, and then again with TSP and water.  Letting it sit for a few days with each step and then cutting while still full from the last step.  Although, with a cutting wheel that brings up the electricity and water problem.  That just doesn't seem very safe either.  I feel like I am missing something that should be obvious.  I am sure one of the guys here has a very clear explanation and doesn't mind helping me out.  I don't want to sound overly cautious, but I think it would suck to survive 4 tours just to get blown up by a damn propane.  I can see my 1st Sergeant shaking his head, now.  

 

[ribwizzard]

I'll be honest with everyone......

I actually duct taped a torch to a 10ft section of angle and stood behind my forklift counterweight and blew the flame into all of the open fittings before I ever got near it with the plama cutter.

Better safe than sorry, right?

 

[jabbo]

RIbwizzard,  that is too funny.  Mostly because I was thinking of a set up just like that!!

 

[05sprcrw]

I have only cut one, but I took a co2 tank that I have around for welding, and just adjusted my flow meeter down pumped the tank full of co2, and then left the co2 running while I was cutting it and didn't have any issues. This is after I cracked all valves to make sure it could air out for about a month before I was ready to start.  I do like the idea of dry ice however it would be much cheaper if you don't have a co2 tank around. Just give the dry ice or co2 tank some time to evacuate the o2 in the tank.

That is why if I can I prefer to get NH3(anhydrous ammonia) tanks when possible. If you crack the valve and make sure its empty *wear gloves long sleeves, mask and face shield I crack it on a windy day and make sure no one is down wind. From there once NH3 hits water it becomes completely inert and safe. So all you have to do is fill the tank up one time with water and your safe to cut. I then do a good hot burn out fire before I weld in my baffles and grates.
[h3] [/h3]

 

[crazzycajun]

A 30-06 at 150 yds preferbly no tracers

 

[sound1]

Go with what you know, tape some det cord along your cut line and ,,,,,

...RUN

Seriously, I found that a good soak with simple green and water cleans the inside of most fuel/gas/propane tanks to almost shiny new. The Co2 thing and/or dry ice and a little water would be added security, 

 

[jabbo]

Thanks guys.  I still think Ribwizzard had the best response.  I laugh each time I read it.  I like the CO2 and dry ice ideas but CO2 can be costly and I have no idea where to get dry ice from.  Simple Green idea is a good one, especially since I use purple stuff for cleaning everything.  Sound1, if I had some det cord, I would need to get another tank because I would blow it just to see how big of a boom it made.  

 

[rustybones]

Wondering about the dry ice trick. Thinking I might give it a try myself.
 

 

[jabbo]

It would be awesome if I could fill the tank with water and then freeze it.  The There would be no doubt about the gas being gone and it would be easier to cut!  I wonder how much dry ice it would take to freeze the take?  This is turning into an experiment, but safety is still the number one priority!!!

 

[jarjarchef]

Since there have been a couple comments on the dry ice. I asked my brother in law more about it. This is what I got....

Make sure the tank is empty of any fuel.

Length X Width X Depth X .25 = The pounds of dry ice needed
8' x 2' x 2' x .25 = 8# of dry ice

After adding the dry ice to the tank allow to sit for 15 min before cutting.

Hope this helps.

Jabbo not sure if you could freeze all of the water, but that would be one big ice cube....

 

[jabbo]

JarJar, thanks for that.  That would be a big ice cube, but I have to say it's got my curiosity up!

 

[jarjarchef]

When you try for the ice cube. Let me know. I have a couple bottle of tequila that goes great with ice.....

 

[jabbo]

After searching for what seems like forever, I finally have found what I believe is the only method actually written and approved.  Basically, after removing all valves and and purging with either an inert gas or water, it should be checked with an explosive gas detector.  These things are expensive but the local fire department should have one and will be happy to check it for you.  If anything is detected, repeat the process until it is safe.  Adding some type of soap, such as dish soap or powdered laundry soap, should make the process much faster because the soap breaks the surface tension of the water allowing it to penetrate every possible nook and cranny, even the pores in the metal.  The same source also assured me that if I was still nervous after these steps have been taken, I could refill the tank with water.  As long as the tank is completely full of water, it is impossible for it to explode.  The reasons for letting the tank sit with water for several days is so the escaping vapors have time to dissipate from the area.  My source was my brother who is a FF and learned this in a class he had to take recently.  He said he would give me the manual with the regulation printed but it is a long read and the only part I really needed is the part I put here.  So I will be doing this as follows.  

1) Relocate the tank to an open area and remove all valves, plugs, etc.

2) After allowing it to air for a few days, I will fill the tank with a solution of water, powder laundry detergent, and TSP.

3) Empty the tank and take it to the FD to be checked for any remaining gasses.

4) Repeat steps 1-3 until tank is safe.

5) Refill tank with water, allowing it to overflow.

6) With water running just enough to keep the tank full, 

and while praying harder than ever before in my life

, I will cut the firebox opening out.

7) Just in case I still can't muster up enough intestinal fortitude to do it myself, I will have my brother do it for me.  He is my younger brother and has always been a pain in the butt, so it will be a win win for me.  Just kidding!!  

 

[thechuck]

Maybe ask the local bomb squad if you can borrow a bomb suit... JUST KIDDING!... but it's a good idea isn't it (and you're thinking about it aren't you?! 

)  

You got this no problem Jabbo

 

[ribwizzard]

I filled my 120 gallon tank with water and dawn dish soap. let it sit for a week, dumped it and filled it again and let it sit another week.  I had to move it into the shop to cut it with the plasma, so I emptied it and did not fill it again before cutting on it. Like I said, I used a 10' section of angle duct taped to a cutting torchand stood behind the counterweight of the forklift and blew flames into it and nothing happened, so I felt confident after that.

I dont really like the ideal of using dry ice alone. Filling the tank with soapy water, your assuring that all propane is pushed out of the tank by the water, and like you said, the soap will help work it out of the pores of the metal. Repeating the step a few times seems like it should get it all out.  Honestly, pulling the valves wondering if there is any propane or presure still in the tank is what made me the most nervoise. Propane is heavier than air and will settle in any low spot like a ditch or sewer until either the wind blows it away or something ignites it. Didnt like having that safety risk on my hands. Luckily, my tank was empty.

Im already thinking about another build, and the option of having some steel rolled to skip that whole step. Its just that I like the shape of the rounded ends on these tanks. Wish I could get my hands on a unused 250 gallon tank.

Thinking about using a trailer like this and mounting it inside, cut the sides so that they are dooors that raise into an awning.....what do you guys think about that??/

 

[mike johnson]

I think that would look GREAT!!

 

[jarjarchef]

I am with Ribwizzard with this one. Even thoe it was my brother in law who told me about the dry ice, and he told me about some very interesting solutions they have used on the field for the gas stations. I would still flush the tank a couple times with water and soap. Then add the dry ice to the tank to form the CO2 Gas inside it before cutting.

I like the trailer. That will be a nice rig.

 

[jabbo]

Ribwizzard, you always know just what to say to make a guy feel better.  I still think the image of you hiding with a torch rigged up is funny as hell, though.  I like the trailer.  I have been tossing around the idea of a concession trailer build myself.  Only much bigger and much later on down the road.  

Chuck, I actually had already thought of the bomb suit.  I just knew better than to ask.  

In all seriousness, I am feeling a lot better about this whole thing.  The less I think about it the more my rational side can kick in and look at it logically.  It really is a common sense issue.  The vapors are a gas.  Gasses are lighter than water.  1+1=2.  So as long as the tank is full of water it is perfectly safe.  Cleaning out the residue with the soap is just extra precaution.  I will get this done and hopefully, soon!!