Gotta build a smoker...

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since I scored this 100 gallon propane tank. My old one has gotten too small for us. A friend who owns a farm was taking it to the scrap yard.My plan this time is to build a reverse flow cooker. That's after I figure out how to make it safe to cut. I'll be using a sawzall rather than a torch. Any advice will be welcome. I'll be asking a hundred questions I know. Attached Images
Reply:Is it empty now? i would take those valves off blow it out with compressed air and let it sit for a week or two then cut it with a torch. You could also try blowing CO2 into it or something. Cutting that with a sawzall will be hell on earth for 2 days of your life.Miller Dynasty 300 DXMiller CST280Miller Maxstar 150 STH
Reply:A technique I've used is to remove all the bungs/fittings and just let it vent for a few days.  Then purge it with water (fill it up and let it sit overnight), then blow it out thoroughly with compressed air before cutting it.  It will have the nasty "gas smell" even after all the gas is gone, due to the chemical residue you'll find inside.  After opening it up, build a  hot fire in it to burn out the chemical residue before proceeding in order to get rid of the smell.Disclaimer:  As stated, this technique has worked for me... Others may have different techniques, and some will tell you it can't be done safely.  Proceed at your own risk... and don't blow yourself up!P.S.  Those tanks are pretty thick... I agree with Silverado on the Sawzall.  Plasma or OxyFuel would be quicker and easier.  If you insist on the Sawzall, stock up on blades and pack a lunch! Last edited by Leadhead1911; 07-15-2010 at 01:14 PM.Work HARDER, not smarter! ------------------------ Miller Bobcat 250Millermatic 251Lincoln Precision TIG 185Hypertherm PM 600Hobart 135 HandlerOxweld 400 FlameMaster
Reply:We went ahead and removed the bungs. Gawd, what a smell! Filled it full of water and plan to let it sit awhile. I don't have oxy/acetylene anymore since I just didn't use it enough to justify keeping it around.  That's how I got to the sawzall phase. I read in a bbq forum where some guy used water for a couple of days and then hooked a hose from his truck exhaust to the tank and let it run. He said that purged it.He cut his with a plasma cutter.  The scrap yard man here in town told me he  just removes the plugs, let's the tank sit a day or so and then sticks his torch to the opening and lets it pop. I ain't doing that.Here it is off the trailer and filling with water. Attached Images
Reply:Try a abrasive blade in a skill-saw. That will work better then the saw-z-all.
Reply:Most people add soap to the water they put in the tank to help loosen up the slime in the tank..The best way to get rid of the smell is to just pour a bottle or 2 of bleach in the tank and let it sit for a day or 2.  This will react with the sulfur compound causing the stink and change it to something that is odorless.If you are paranoid about cutting into it, go pick up a few lbs of dry ice.  Smash it up and dump it into the tank once about 1/2 the water has been poured out.  This will form co2 gas which is heavier than both air and propane and displace any that remained in the tank.
Reply:Originally Posted by GabZipTry a abrasive blade in a skill-saw. That will work better then the saw-z-all.
Reply:I have never cut a propane tank! I have however, welded on live gas lines. But, A good friend of mine (who owns a propane company ) told me to remove valves and fill with water and build a fire under it. Then let the water boil and thus remove all old propane.. This is just another option for you.
Reply:I prefer cutting them as full of water as I can get them.  Less volume for gas+air mix means less boom.  You'll probably have a 2" diameter hole once you remove the valve.  If you do have any residual gas and you get it ignited, the pressure trying to shove 1 gallon of burning gas+air through that 2" hole will be much less than trying to shove 100 gallons of burning gas+air through the hole.  Once you get a larger hole cut (1 sqft area maybe) I'd be comfortable emptying the tank to allow you to cut other holes, doors, etc.My choices on cutting methods:1) plasma (starts cutting without preheat, fast cutting, easy)2) O/A torch (fast cutting, easy)3) abrasive cutoff wheel (slower cutting with some elbow grease).4) sawzaw (even slower and more elbow grease)5) hacksaw!!!! (slowest and most painful)Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Thanks for all of the great input. I'm a newbie at this. Right now it's just sitting full of water, but man does it stink. The bungs are on the top of this tank and it has four feet welded to the bottom. I think they show in the photos. I plan to mount it on pilings since I really don't have anywhere to tow it to. I have an old Ford 8N that will pick it up if it needs to be moved. What I wonder is, whether I should cut off the feet and weld them on the top side so I have a smooth surface for the door. In other words, just flip it upside down.  The four holes are a lot to fill, and would show, but removing the four feet and getting them back right would be hard too.
Reply:Water is not the safest way. The metal is porous and holds the gas in it. this is why you will smell the gas. Take a hose and run the exahaust from your vehicle and let that run in there for at least a half an hour. This will take out all of the oxygen and the heat from the exahaust will help boil the gas out of the pores. Keep the gas running while you start cutting.Yes I can tack it for you.    I know that won't hold but that is what you asked me to do.  Millermatic 350P XR Aluma-Pro push/pullMillermatic 185/spool gunMiller Dialarc 250 HF Water cooledThermal Dynamics Plasma
Reply:Originally Posted by got aluminumWater is not the safest way. The metal is porous and holds the gas in it. this is why you will smell the gas. Take a hose and run the exahaust from your vehicle and let that run in there for at least a half an hour. This will take out all of the oxygen and the heat from the exahaust will help boil the gas out of the pores. Keep the gas running while you start cutting.
Reply:I left the "feet" on mine and used them as mounts for my trailer. I also cut the tank heads off each end and built fire pits out them, of course I had enough plate to use for both ends so that worked out pretty good for me. I mainly did it that way just so it wouldn't look so much like an old Propane tank when I was done.
Reply:Have any argon?
Reply:Nah. Got a little left in a tank but not near enough. I drained the tank today and was surprised to find almost no odor. Just a faint oil smell. I'm thinking I'll let it sit empty a couple of days, maybe longer, then fill it again with water and cut it.Marcus, what did you do about the bung holes on your grill? If I leave the tank right side up I was planning to cut them off and weld up the holes. There are four holes in the top of this tank. That was why I thought originally that I'd just flip it.
Reply:i always fill with water and soap rinse it out then let it dry get steel wool unroll it and make a fuse. attach a + and - wire to your 6" fuse and touch the wire to a car battery if it dont blow its good to cutLincoln Power Arc 4000 Thermal Arc Fabricator 252 iThermal arc 186Thermal Arc 26 tigTweeko 200 amp spool gunHobart AirForce 400WP-17V-12R
Reply:I realize now there must be as many ways to cut these tanks as there is people who've cut them. I thought about your way assassin, and it's a good one,  but I'll probably chicken out on fire. I remember the scrap metal guy telling me he just sticks a torch to the valve hole and "pops" them. I can only imagine what that means.
Reply:Originally Posted by hvwMarcus, what did you do about the bung holes on your grill? If I leave the tank right side up I was planning to cut them off and weld up the holes. There are four holes in the top of this tank. That was why I thought originally that I'd just flip it.
Reply:Honestly, If you fill the tank with soap and water, the propane will come out. It does not bond or stick to the insides of the tank. The smell may remain, but that's not an indication of the presence of propane, rather its a chemical oil like substance that does the "smelling up" of propane.  It can remain around, but that won't make it blow up or anything. You can get it on your clothes and after several washings, they will still smell like a visit to the hog parlor, but that doesn't mean it will blow up in the dryer.  Propane volatizes and becomes a vapor when the tank is opened.  It will leave eventually.  Definitely though don't cut it where you drained it, because the vapor can hang around like a low fog for a while...Move it and wash it out.If you aren't sure, fill it up and drain it twice...won't hurt, but if you let it open up for a few days and then water it up and drain it there shouldn't be any propane left.Still, any advice isn't legally binding...  You cut at your own risk and peril.  But cutting propane tanks has been done safely many times.  Look at the bright side, you won't cut unsafely but one time....after that, if you survive, its a piece of cake.Last edited by lugweld; 07-17-2010 at 01:58 AM.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Originally Posted by hvwI realize now there must be as many ways to cut these tanks as there is people who've cut them. I thought about your way assassin, and it's a good one,  but I'll probably chicken out on fire. I remember the scrap metal guy telling me he just sticks a torch to the valve hole and "pops" them. I can only imagine what that means.
Reply:Originally Posted by hvwNah. Got a little left in a tank but not near enough. I drained the tank today and was surprised to find almost no odor. Just a faint oil smell. I'm thinking I'll let it sit empty a couple of days, maybe longer, then fill it again with water and cut it.Marcus, what did you do about the bung holes on your grill? If I leave the tank right side up I was planning to cut them off and weld up the holes. There are four holes in the top of this tank. That was why I thought originally that I'd just flip it.
Reply:As far as the bungholes, on my tank I have the fire box and on the other end I put a large smoke box, so I had plenty of scrap to use to fill in where I cut out the bung holes. I just cut around them so I could lay a piece of scrap over the hole, traced around it and cut it to fit.
Reply:Well, you guys were right. Cutting  this with a sawzall was a non-starter. I wore out three blades in about 45 minutes and had cut only 13 inches. About 180 left to go. Only other tool I had for the job was a skil saw. Got it and within an hour the rest of the door was cut.Pookie was right about the pucker factor too.  Real high when you first make sparks. It goes away after a while and I think that's because you're too tired to care if it blows up. The tank is in great shape inside. I'm glad this phase is over. Attached Images
Reply:The skill saw does make a nice cut doesn't it?
Reply:looks like you ended up with the four holes on the bottom..rememeber   you gonna need  drains and a cleanout to move all that ash and pigfat out of the box.....Yeah, there are four bungs in the bottom. I'll probably cut three off and use the largest for a drain. The gauge hole is not threaded, just a very tight sleeve fit.  All the bungs are welded inside the tank and outside. And I mean big welds. I may just buy threaded plugs.You're right Marcus, the skil saw makes a good clean cut. Much better than I could do with a plasma cutter or torch. Either of those would be faster but like someone on here said, you gotta make do with what you have. This is going to be a low budget deal out of necessity.I was surprised that the door weighs 71 lbs. Since I don't want to use counterweights I'll need to have more than one door. Looks like more skil sawing on the horizon.
Reply:We made a little progress but in this heat it's tough to think about a smoker. I don't know why stuff like this always sounds fun until you get into it. We made the hinges from 1/2" tubing and 3/8ths rod. The little hole is for oiling. The middle door was an afterthought that turned out to be a pretty big job. It opens when either of the other two doors are opened. Or you can open it alone if you just felt like sticking your hand in there for some reason...or a very small chicken. I decided to make the middle door so we wouldn't lose all the heat every time the doors were opened. Firebox is next up. Attached ImagesLast edited by hvw; 07-24-2010 at 07:47 PM.
Reply:I finally finished mine up Friday.  Painted it mid afternoon, and seasoned it that night.  Cooked on it yesterday.  The heat index has not been below 105 here in a week.  I have another one to start for the camp, but I just can't get interested in it with the weather like it is.  You are progressing nicely.
Reply:Interesting Thread...However, if the 'simplest' of cleaning methods and purging methods will allow the tank to be cut will little or no issue at all....  This is one reasons why the individual at the metal yard is able to 'POP' the tanks.  However, I wouldn't want to be NEAR him if he was popping the tank shortly after removing the bung or valve....  Propane will 'Pool' around the ground until it is 'dispersed'.Contrary to popular belief (and most Hollywood Movies), propane Tanks DO NOT explode but can and will travel decent distances if FULL and punctured.  Throw it in a Fire, Burn it with a Torch, it does not matter....  The tank will rupture at the safety valve, and if the valve WILL not do what it's supposed to, then the tank will likely 'rupture' eventually and react somewhat more violently (not as bad as a CO2 tank either..), but it WILL NOT explode.  The ONLY tank to have ever done that I know of, was an actual TANKER and EVERYTHING has to be 'just right' for that to happen.  Fire, leaking and fractured tank and perfect 'atmospheric' conditions that allows the gas to remain in the vicinity, 'pre-ignition'.Cheers,Miller Diversion 165120 amp Buzz BoxVictor Oxy/Ace Oxy/LPGSmith "Little" Oxy/LPGHypertherm Powermax 30Lot's of Misc. tools n' crap....
Reply:Progress is slow mostly because of the heat. But we're getting there. This has been a fun father/son project. Just hope the thing works! It's been a make it up as you go deal. Attached Images
Reply:What I can see of it looks pretty good. Be sure to post some pictures of it when finished.That "terrible smell" isn't propane. Propane has very little odor and it is "stenched" with ethyl mercaptan (I think that's how it's spelled) so you will know immediately when you have a leak. It takes a very minute amount it is so strong. Just a few cc's per 1000 gallons although I've forgotten how much. It is the same substance that a skunk squirts on you if you stir him up.  About 45 years ago I spent a year in a gas plant and got to hook up 55 gal. barrels of it on the loading racks. The barrels even had a picture of a skunk on them. The concentrate REALLY stinks.I've never cut into a propane tank but have cut into many crude oil vessels and the same procedure would work with any container that has contained flammable liquids. I won't elaborate except to say water was always involved. Sometimes just water and sometimes in the form of steam. It all depended on the circumstances and we had written procedures to follow. Loved filling out those hot work permits.A word about using engine exhaust. I've used it in some smaller containers in conjunction with an explosion meter. Ever time when the engine was run at an idle the exhaust from the container would check "hot". By running the engine at 1200 or so rpm the exhaust would clear out and show zero on the meter.Last edited by Oldtimer; 08-06-2010 at 06:54 PM.
Reply:looks great.  I'm in the middle of a smoker project myself.  I'm making mine out of a 60 gallon air compressor tank.  From the pictures, it looks like there's a little rust inside the tank, is that gonna be a problem?  or will you be removing the rust... if so, how?  (crossing my fingers, hoping its not sanding wheels and a respirator mask)
Reply:Getting the rust out is definitely the pits. I've been using a wire wheel to get the flaky stuff off along with a shop vac to keep most of it off of me. Someone suggested seasoning it by burning cardboard in it. I think it was Pookie. I'll probably try that. As of now, the firebox is finished and mounted, the two cooking grates are in. What I have left to do is make a latch for the firebox and handles for the main tank. This is a tunable plate smoker so I have to install the plates. Oh, I don't have the stack in yet. And it's going to be mounted on concrete blocks which I haven't laid yet. I guess I'm not almost done after all. But I'm a lot closer than I was.
Reply:Getting closer. Still a lot to do, front shelf and paint at least,  but we decided to go ahead and season it. Used cardboard and maple logs. Hope to be cooking next weekend. I want to put a propane starter in it but haven't figured out how yet. The thermometer is just there temporarily. It's going to end up in the door but I had a convenient hole to put it in from a mistake. One of many. Attached ImagesLast edited by hvw; 08-15-2010 at 07:39 PM.
Reply:Forgot one I wanted to include. It burned in good. Attached Images
Reply:A done deal, finally. I had to get this out of my system and now it's out. I doubt I'll be doing it again. Now, if the rain will let up we'll give it a go. Attached Images
Reply:Sorry to revive a thread that's been idle for 2 months but I had a couple of comments, one of which is quite important.Firstly and most importantly, I didn't want this comment to go unchallenged for the obvious safety reasons, lest somebody do something foolhardy based upon it:Contrary to popular belief (and most Hollywood Movies), propane Tanks DO NOT explode...  Throw it in a Fire, Burn it with a Torch, it does not matter....  The tank will rupture at the safety valve...
Reply:Originally Posted by AquafireSorry to revive a thread that's been idle for 2 months but I had a couple of comments, one of which is quite important.Firstly and most importantly, I didn't want this comment to go unchallenged for the obvious safety reasons, lest somebody do something foolhardy based upon it: Quite wrong! As a firefighter, one of my biggest fears was a BLEVE (pronounced like Chevy).  BLEVE's aren't imaginary or a creation of Hollywood- firefighters and others have died as a result.    There are lots of videos out there of LPG vessels exploding and many more of the devastation that resulted.  I won't split hairs about the types of explosion or differences between rapid combustion/explosion and detonation, but suffice to say that all it takes is for the internal volume of gas in the vessel to increase faster than the safety valve can release it and you can have an explosion.  If you combine an ignition source and an "explosive" gas inside the vessel, you may have catastrophe.I agree that the result may not necessarily be a 'fragmentation effect' and shock-wave/fireball that many expect based on movies; and yes, conditions do have to be "right" for it to happen.  I've seen occasions in which intact propane tanks survived some pretty big conflagrations very close-by, even direct flame impingment without any issue (it happens all the time without mishaps).  That said, they still deserve a great deal of respect.  I'll bet there are members on this board that know of someone that is no longer with us because they thought "Awww, it can't explode!" or didn't treat an LPG vessel with the respect it deserves.Finally, and come to think of it, maybe THIS is more important :  You ended up with a pretty nice smoker, HVW!  Great work, and thanks for sharing it with us!
Reply:Your smoker looks good. I have a question about the placement of your exhaust.It has been my experience in cooking on serveral different smokers that the stack should be at the opposite end of the smoker from your firebox. This draws the smoke (and heat) throughout the smoker.If you want to change this, just put a "lid" of some sort on your existing stack and make a new one at the other end. On my smoker, the "lid" is made from 3/8 plate cut to be just a litle larger than the pipe and attached on a pivot point. I use it in conjunction with the incoming air vents to help in regulating the temp.Just my 2 cents.Happy smoking!
Reply:Originally Posted by adelgado7Your smoker looks good. I have a question about the placement of your exhaust.It has been my experience in cooking on serveral different smokers that the stack should be at the opposite end of the smoker from your firebox. This draws the smoke (and heat) throughout the smoker.If you want to change this, just put a "lid" of some sort on your existing stack and make a new one at the other end. On my smoker, the "lid" is made from 3/8 plate cut to be just a litle larger than the pipe and attached on a pivot point. I use it in conjunction with the incoming air vents to help in regulating the temp.Just my 2 cents.Happy smoking!
Reply:Thanks for the thumbs up, guys. We built a small smoker a couple of years ago with the exhaust on the opposite end from the firebox. It worked fairly good but not nearly as good as this plate smoker.  The firebox side was always hotter than than the exhaust side.  So on this one, rather than weld in a solid piece like the traditional reverse flow smoker, we use removable plates which allow for easy temperature adjustments. Both ends stay within a few degrees of each other.  It also allows the smoker to double as a huge grill by removing the plates.  This thing has cooked some delicious food for us. I've been real happy with it. It ended up costing about $300.00 which was a pleasant surprise.