Cutting USED and NEW Propane tank? How?

[psychbiker]

I have a used propane tank upside down with valve and bleeder open currently. From my research, cutting in half is a **** shoot. The water method isn't 100% safe.

What about NEW empty bernzomatic tanks inside homedepot? They say pre-purged. Does this mean with inert air and not gas?

I'd feel much safer cutting that tank open even if it costs $40.

[98neon]

I am in the lp business. Most new tanks are vacuum purged so they can be transported without hazmat. We dispose of bad tanks by first airing them out then filling with water. After that they are cut up with a sawzall. Little chance of ignition as tanks still have water in them while cutting.

[ReloaderFred]

I've cut three old propane tanks to make smelting pots. They work great, by the way!

With all three, I first took them to the range and ventilated them with several .44 caliber holes in the top part, which I recycle with other scrap metals. Then I let them sit outside for about a week upside down (propane is heavier than air) until I'm in the mood to cut them open. I've used a metal cutting wheel in a sidewinder grinder and haven't had a problem yet. It takes a whole wheel in a 4" grinder to do one. I did squirt water in the first one and then drained it, but not the second two.

Don't make your pot too deep or it will be hard to dip the molten lead out with a ladle. On a 20 pound tank, just above the weld worked best for me, but if you get too close to the weld, you'll be cutting a double layer of steel.....

And don't forget to put handles on it. They're hard to get hold of with any amount of lead still in them. The paint is also the toughest I've ever encountered. Even after multiple smelting sessions, it's still powdery and gets all over everything if you rub against it. If you have a sandblaster, I'd use that to remove it, but I don't have one....

Hope this helps.

Fred

[country gent]

I did mine simply. I vented for a period of time. also pressurized and bled out several times with compressed air, then soap and water wash. I decided where I wanted the cut at and carefully wrapped 2 wraps of heavy masking tape around at edge with no wrinkles and edges matching, this gives a straight true cut around tank. I did the cut simply with a hand hacksaw. Started at a spot cut thru and worked around following tape line carefully. Once cut grind or file to tape edge. I also cut a 3" ring and welded it to pot for a bigger dia support ring and heat shield. a 1 1/2" hole saw is handy to cut 8 or 10 half holes around the top of this ring so heat can flow up and thru. I cant wont recomend cuttoff ginder wheels, tourches, or spark producing tools as any failure to completely clear the used tank can be hazaedous. Pick up a good hacksaw and some medium to fine toothed hack saw blades it dosnt take that long or hard to do.

[bdicki]

What about the stink? Doesn't the smell linger after the tank is empty? A friend was doing some scrapping and cut a tank in half and put it in the back of his truck with the other scrap, it smelled so strong that somebody called the law and they got pulled over thinking it was a propane leak.

[bstone5]

Have cut several 20 pound tanks, take the valve out, fill with water, pour water out and cut after letting set for a day or two.

Use a cut off wheel in an air grinder for cutting around the tank.

[dragon813gt]

The mercaptan will dissipate. The smell is only temporary.

[Mike W1]

What lingers after you fill with water and empty is the additive for smell, not gas. Used an electric angle grinder with I believe was a .045 disk. Not a problem but cut either above or below the weld line which is actually close to 2" overlap.
Did mine above and then cut it below later as I decided it didn't have to be that deep. The smell will vanish when you heat it up and it's no big thing.

[Tailhunter]

Grinder with a cutting blade.

My pot is able to do 150 pounds comfortably.

[NavyVet1959]

I empty it as well as possible via the valve and then when I'm sure there is no pressure left in it, I drill a 1/8" diameter hole either near the valve with an air drill to relieve any pressure that is left in there. I then drill another hole on the other side of the tank. I use these as pilot holes to drill a larger holes that are the size of whatever air fitting that I have handy. I hook the tank up to my air compressor and let it flush any residual propane with the air coming in one hole and the exhaust going out the other hole. You could also put water going in one hole until it comes out the other hole if you orient the tank correctly. I then mark a line around the tank by sitting the tank on a flat surface and then using a board of the appropriate length as a spacer and working my way around the tank and marking a line on the tank at the top of the board. I then take an air powered cut-off tool and lightly score the line. This gives me a bit of groove to follow and it seems that I am more likely to keep a straight line this way. The finished edge is pretty smooth, but I make it slightly better by turning the tank upside down on a concrete slab and then "sanding" the top with the concrete surface. Then just weld on a couple of bent pieces of rebar for handles and a wider base so that it will be more stable. This also works with air-conditioner refrigerant tanks, but I don't bother flushing them out.

[merlin101]

Instead of drilling the holes in the tank it's more fun to shoot em!
The stink hangs around for several days even after filling with water, don't worry just go ahead and cut it and start smelting

[Three44s]

.............................. I hook the tank up to my air compressor and let it flush any residual propane with the air coming in one hole and the exhaust going out the other hole. ...............................................


Spot on!

Three 44s

[MrWolf]

I cut mine with a sazall. Was easy and fast ( after being upside down and then filled with water).

[dolfinwriter]

Ok, I got this set up with a bunch of WW ingots.

152920 152921 152922 152923 152924

Anyone recognize this? I'm thinking this was something somebody made from scratch, from assorted parts. But if by chance this was some kind of common set up years ago, maybe somebody has already engineered some kind of adapter or conversion for it. That valve and stem on the bottle are the problem. There is still a good amount of propane in it, but I don't know what good the thing is after that.

I only see it continuing to be useful if I can come up with an adapter to connect a new type bottle to that fitting where it screws into the old rusty bottle. The top crown/handle part on new bottles is about twice the diameter of the crown on this old bottle, so that's a non-starter.

I've spent enough time in shipyards that I would never try to even drill a hole in this thing without purging it. I spent some time today trying to find an outfit that would be able to purge this old bottle when it's empty, either with nitrogen or with CO2, and that seems to be a non-starter also.

My thought was that if I could at least purge the bottle, I could cut some openings in the old bottle and continue to use it as a stand for the burner, and then rig up an adapter to a new bottle. I have a couple of old brake rotors around here that I could toss into the bottom of it to give it more stability with the bottle empty and cut open.

Seems like a lot of trouble though, to save how much $ on some new kind of rig that I don't have to re-engineer. I love to tinker and I have quite a knack for jury-rigging things, but I really am kind of attached to all my body parts, and my eyes, and I'm quite averse to having burn scars, or worse...

[waltherboy4040]

Ok, I got this set up with a bunch of WW ingots.

152920 152921 152922 152923 152924

Anyone recognize this? I'm thinking this was something somebody made from scratch, from assorted parts. But if by chance this was some kind of common set up years ago, maybe somebody has already engineered some kind of adapter or conversion for it. That valve and stem on the bottle are the problem. There is still a good amount of propane in it, but I don't know what good the thing is after that.

I only see it continuing to be useful if I can come up with an adapter to connect a new type bottle to that fitting where it screws into the old rusty bottle. The top crown/handle part on new bottles is about twice the diameter of the crown on this old bottle, so that's a non-starter.

I've spent enough time in shipyards that I would never try to even drill a hole in this thing without purging it. I spent some time today trying to find an outfit that would be able to purge this old bottle when it's empty, either with nitrogen or with CO2, and that seems to be a non-starter also.

My thought was that if I could at least purge the bottle, I could cut some openings in the old bottle and continue to use it as a stand for the burner, and then rig up an adapter to a new bottle. I have a couple of old brake rotors around here that I could toss into the bottom of it to give it more stability with the bottle empty and cut open.

Seems like a lot of trouble though, to save how much $ on some new kind of rig that I don't have to re-engineer. I love to tinker and I have quite a knack for jury-rigging things, but I really am kind of attached to all my body parts, and my eyes, and I'm quite averse to having burn scars, or worse...

It is a plumbers furnace, sounds like they make adapter kits for it.

http://castboolits.gunloads.com/showthread.php?8817-Saving-an-older-plumber-s-furnace

Probably could just sell the plumbers furnace to someone who wants it and buy a byou turkey fryer from home depot for $45

[dolfinwriter]

Probably could just sell the plumbers furnace to someone who wants it and buy a byou turkey fryer from home depot for $45

Thanks for that. Did I see a thread where some guy was having trouble getting his lead to melt in a turkey fryer? Would I need any other special pots for that? I can't imagine a turkey fryer would be very thick stuff and burn/melt through quickly?

[country gent]

You need to watch turkey friers pots as most are aluminum and not heavy strong enough for heat and wieght of melting lead. Alot cut a propane tank to make the pot or use a cast Iron dutch oven. If using the cast iron dutch oven. Start flame low and warm pot some first bring up in increments to temp. FAst expansion of full heat on a cast iron pot can cause it to crack. A steel pot cast iron pan, pot, dutch oven, or cut down and repourposed 25LB propane tank works well. Avoid aluminum as at lead temps it softens or weakens to much.

[waltherboy4040]

Thanks for that. Did I see a thread where some guy was having trouble getting his lead to melt in a turkey fryer? Would I need any other special pots for that? I can't imagine a turkey fryer would be very thick stuff and burn/melt through quickly?

yes I believe they sell a high pressure and low version of the same turkey fryer so get the high. I don't believe it comes with a pot, but never use aluminum pots for melting lead use ss or cast. I use a 7 quart stainless steel pot from good will with a top on a old bbq grill side burner.

[dolfinwriter]

Is there a thread where there are photos of what different guys are using to melt their lead, pewter, zinc, etc.?

I have another burner that I could use with the green camping type of bottles, or an adapter that would connect one of the bigger bottles that can be refilled or exchanged. BUT it's kind of a funky two legged contraption that would suit at an angle under the pot, and I would still need some kind of stand strong enough to support the melt pot full of lead.

If I see what other guys are using, then I can get some ideas for my own.

[wistlepig1]

I opened the valve on empty tank, turned upside down, walked away. A few days later removed the valve {the hard part of the whole job}, filled tank with dish soap and hot water, set out in sun and walked away. A few days later I dumped soap/water, filled with fresh water, got out 4" grinder, dumped water and cut it below weld. No problem and great smelter.

I did add handles and a wide base, the is a good idea, no one wants to spill 100 lbs of lead on their new boots.

[lightman]

Dolfinwriter, there is a sticky at the top of this page that shows a few smelting set-ups. Here is mine;

http://i788.photobucket.com/albums/yy164/PTheodo/smelting/038.jpg (http://s788.photobucket.com/user/PTheodo/media/smelting/038.jpg.html)

The burner is a high pressure and homemade. The pot is a recycled cover from a railroad tank car valve, about 14 in diameter and 12 inches deep. I can do 350 to 400# and it will be liquid in around 20 minutes. I've added a base plate and wind sheilds since this picture was taken.

[MrWolf]

Here is a link to my converted Weber grill to my smelting station:

http://castboolits.gunloads.com/showthread.php?240632-Weber-Smelting-Station

[45-70 Chevroner]

I've cut three old propane tanks to make smelting pots. They work great, by the way!

With all three, I first took them to the range and ventilated them with several .44 caliber holes in the top part, which I recycle with other scrap metals. Then I let them sit outside for about a week upside down (propane is heavier than air) until I'm in the mood to cut them open. I've used a metal cutting wheel in a sidewinder grinder and haven't had a problem yet. It takes a whole wheel in a 4" grinder to do one. I did squirt water in the first one and then drained it, but not the second two.

Don't make your pot too deep or it will be hard to dip the molten lead out with a ladle. On a 20 pound tank, just above the weld worked best for me, but if you get too close to the weld, you'll be cutting a double layer of steel.....

And don't forget to put handles on it. They're hard to get hold of with any amount of lead still in them. The paint is also the toughest I've ever encountered. Even after multiple smelting sessions, it's still powdery and gets all over everything if you rub against it. If you have a sandblaster, I'd use that to remove it, but I don't have one....

Hope this helps.

Fred
The paint on propane tanks is probably epoxy based. I worked for Chevron for 30 + years ( tanker driver ) and for at least 25 of those years the trucks were painted with epoxy paint.

[ReloaderFred]

You're probably right about the paint. It sure is tough stuff. I just need to take a wire wheel to it, but I never think about it until I'm ready to smelt another batch of lead, and then it's too late (again).

Fred

[iraiam]

I bought a warped Lodge cast iron dutch oven at a thrift store for a few bucks, it had already been mistreated so it was a little warped and the lid didn't fit like it should. works great for smelting.

If your set on cutting the tank, fill it with water, that will guarantee any gas is forced out. when the water is emptied it will be replaced by harmless atmosphere.

[psychbiker]

My dad (65 year contractor of 30 years) was losing my his patience with me being overly cautious with cutting the tank. When I was at work, he hacked the brass valve off, drilled through it (***!!), filled with water a few times then cut it when it was filled with a grinder I think.

I currently use the top half as a lid. Melted through 200lbs of wheel weights Wednesday. Not bad.

http://i.imgur.com/sf66DxLl.png

[Tazza]

Nothing wrong with being overly cautious :)

I drilled and welded a big household LPG (propane) tank years ago to use as a water separator for an air compressor. I removed the valve and inverted it to allow any gas drain out. I carefully drilled a hole in the base to for a water drain valve. I think i used more air to purge it (been a while), then drilled a hole in the side for air to come in and welded a nut to it.

Nothing caught fire, i still have all my fingers.

Skip forward to about a month ago, i cut this tank up with a plasma cutter and turned it into a wood fired melting pot. As it ran as an air tank, there was not a drop of gas in it still, so the plasma cutter was safe to use.

[NavyVet1959]

Nothing wrong with being overly cautious :)

I drilled and welded a big household LPG (propane) tank years ago to use as a water separator for an air compressor. I removed the valve and inverted it to allow any gas drain out. I carefully drilled a hole in the base to for a water drain valve. I think i used more air to purge it (been a while), then drilled a hole in the side for air to come in and welded a nut to it.

Nothing caught fire, i still have all my fingers.

Skip forward to about a month ago, i cut this tank up with a plasma cutter and turned it into a wood fired melting pot. As it ran as an air tank, there was not a drop of gas in it still, so the plasma cutter was safe to use.

All I can say is that ya'll must have a lot smaller tank size for LPG for a house than we use. Around here, 500 gallon is probably the most popular size and you sometimes see the 250 gallon size up for sale (probably by someone upgrading to the 500 gallon size).

[Tazza]

Sorry, forgot about the fact you guys use tanks that are the size of a small car.

The one i used was a 45kg one, they stand about a metre tall (3 foot)

Think of the lead we could melt using the end of one of the BIG tanks :)

[NavyVet1959]

Sorry, forgot about the fact you guys use tanks that are the size of a small car.

The one i used was a 45kg one, they stand about a metre tall (3 foot)

Think of the lead we could melt using the end of one of the BIG tanks :)

Around here in Texas, some people use the 250 and 500 gal tanks to make into BBQ pits.

We use the 5 gal LPG tanks for smelting pots.

[Tazza]

Must be us slack aussies, the pits i generally see are when somene digs a hole in their lawn and lights a fire and cooks a whole pig in the coles.

I have seen people selling 44 gallon drums cut in half length ways for fire pits too.

[dikman]

Navy, here we're not allowed to buy/own any tank bigger than a 20 lb. bbq tank. The bigger ones (100 lb. up) are owned by the company supplying the gas. (I should clarify, I'm talking refillable tanks here: we can buy an old tank, but it's illegal to refill it). Most houses on LPG tend to use 2 100 lb. tanks, when one is empty the company swaps it for a full one. We actually had one of the big suckers for a while, but unless you're a real heavy gas user they tend to discourage their use.

As for cutting the tanks, there have been many posts about that. The first one I did I vented it, filled it with water, let it stand and then cut with an angle grinder while it was still wet. The next few I simply opened the valve and inverted them for a couple of days, removed the valve (as has been said, the hardest part of the process!) and cut away with the angle grinder. After it's been vented for a while there's little chance of there being a sufficient gas/air mixture to be a problem. People tend to panic because they can still smell the Mercaptan, which will linger long after the gas is gone.

That paint is most likely epoxy, it's really horrible stuff. The first time I tried to remove it with a sanding disc in a drill - a lot of work and messy! The next time I fired up the forge and cooked the pot, the paint then came off with a wire brush.

[Tazza]

Dikman is spot on, over here we have limits on what we can own, even if we own it, that doesn't mean you can find someone to fill the rotten thing either....

We used to be able to buy our welding tanks, now they expect us to rent them, even though you bought them out right 20-30 years ago, they will not honor that now.

The smell sure does stick around. I needed something to hold refrigerant from old AC units that were being scrapped, better that than letting it go into the atmosphere. I pulled a vacuum on the tank before recovery, the tank still stank, even though there was not a drop of air or gas in there.

[NavyVet1959]

Around here, you can buy or rent your tanks. Of course, buying makes more sense financially. Most urban locations will have natural gas distribution pipelines to each house, so propane is normally just used in more rural locations. Propane tanker delivery trucks are usually around 5000 gallons from what I understand.

http://blog.amerigas.com/wp-content/uploads/2012/06/AmeriGas-Bobtail-Truck.jpg

You call your local propane seller and they will send one of these trucks to your property. The driver will run a large hose from the tanker to your tank and fill it up / put as many gallons in as you ordered. It's more expensive per BTU than natural gas, but rural locations don't have natural gas distribution lines.

Propane prices vary throughout the year, so with a large tank, you try to fill it up when the prices are the lowest.

http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=W_EPLLPA_PRS_NUS_DPG&f=W

[dsbock]

I've cut two 20lb tanks using the following procedure.

Vent the tank to release gas pressure.
Remove the valve. (Usually involves profanity)
Fill with water and empty a couple of times.
Leave upside down overnight.
Using a metal cutting blade on my table saw, rotate the tank against the blade, gradually cutting through the tank. (Make sure to wear eye protection and a hat)
I also cut another section from the tank to use as a wind shield.

Works for me.

David

[dolfinwriter]

It is a plumbers furnace, sounds like they make adapter kits for it.

http://castboolits.gunloads.com/showthread.php?8817-Saving-an-older-plumber-s-furnace

Probably could just sell the plumbers furnace to someone who wants it and buy a byou turkey fryer from home depot for $45

I've been checking the plumber's suppliers in the San Diego area, and the retired plumber/pipefitter I got this from has been checking his suppliers, and nobody has this stuff anymore, because "Nobody uses lead anymore" (for plumbing purposes).

Anyone know where to get these adapters and items like the stand that will put the burner closer to the ground and therefore safer?

Tomorrow I'm taking the whole rig to a company that does nothing but propane and tanks and fittings, but I don't have much confidence that they're going to have anything or be able to do anything economically. Maybe it's fair to say these things are dinosaurs, and their extinction is just part of a larger plan to render our guns useless by attacking the ammo supply from all angles? I will post back with what I find out. Maybe what I need is on ebay or something, but I just don't know what to search for.

[NavyVet1959]

I really don't think I would put a large pot of lead on one of those plumber's furnaces. I would make a stand for the pot of lead and leave enough room underneath it so that I could slide the heat source (i.e. plumber's furnace) underneath it. Of course, you could also just dig a hole and put the tank as low as you want. :)

Just looking at your plumber's furnace, it appears that there is not even a regulator on the tank valve, maybe just a volume flow valve. It's a very simple type of burner -- just a small orifice blowing gas up through a large diameter tube/pipe where air gets sucked in due to the venturi effect.

Do you have natural gas at your home? That's going to be a cheaper fuel cost than propane.

[Tazza]

We get propane trucks that deliver to properties that don't have natural gas too, i don't know the price they charge though.

Our prices seem to stay pretty steady for the bbq size bottles. There are two main companies that do a swap and go deal, you drop in an empty cylinder and buy a full one. They only fill them to 8.5kg and charge about $22 at the local hardware shop.

[dolfinwriter]

It is a plumbers furnace, sounds like they make adapter kits for it.

http://castboolits.gunloads.com/showthread.php?8817-Saving-an-older-plumber-s-furnace

Probably could just sell the plumbers furnace to someone who wants it and buy a byou turkey fryer from home depot for $45

So how would I find someone who wants it? I can't post on S&S yet. And if they want the tank also, that's probably going to be local pickup only for obvious reasons. Thanks!

[NavyVet1959]

So how would I find someone who wants it? I can't post on S&S yet. And if they want the tank also, that's probably going to be local pickup only for obvious reasons. Thanks!

Place an ad on CraigsList or Armslist?

[dolfinwriter]

Place an ad on CraigsList or Armslist?

Nah, that's too easy! :wink:

Actually, I use Gunbroker. Since I can't post it in S&S here, it's under this same username on Gunbroker.

By the way, since I'm going to sell this one and I'm looking at new ones now, does anyone have any idea what kind of BTU output these old ones have? The one I saw today is $153 and puts out 60,000 BTUs. Seems like an awful lot, but I imagine it takes an awful lot to melt 100# of lead or more at a time.

Just wondering if I shouldn't look for a smaller one and less expensive one. I'll probably be doing 70-80 pounds in the pot at a time. I just did a quick back of the envelope calculation and came up with 1440 BTUs to raise the temperature of 80 pounds of lead from 80 degrees to ~680 degrees ((Specific heat capacity of lead) X (80 lbs of lead) X (600 Degrees Fahrenheit) = (.03 BTU/lbm-Deg F) X (80 lbm) X (600 Deg F) = 1440 BTUs

That must be 60,000 BTUs per hour. That means 1440 BTUs in less than two minutes. I have to be doing something wrong...

[Tazza]

Have a squiz at another thread on this:
http://castboolits.gunloads.com/showthread.php?113638-How-many-BTU-s-burner-to-melt-lead

[rondog]

Jeeze, I just use a rusty old cast iron dutch oven I found at a Goodwill store for a couple of bucks and my old turkey fryer burner/stand.

[NavyVet1959]

That must be 60,000 BTUs per hour. That means 1440 BTUs in less than two minutes. I have to be doing something wrong...

It doesn't take too much of a heat source if you aren't wasting a lot of BTUs due to wind, escaping up the sides of the pot, lack of insulation, etc. The vast majority of us don't have these perfect pots, so we compensate by having a larger burner.

If you have natural gas at your house, it is easy to set up a banjo type burner that will work for smelting lead. Maybe it won't be quite as fast as a high pressure LPG burner, but I find that it is fast enough for my needs. It can be set up cheaply enough that it will probably pay for itself within the first one or two smelting sessions.

[jmorris]

I have never cut up an old one because I can always swap them out for a new one at homedepot, when they go out of cert.

Have cut the fittings off of the 1lb cans before, I just shoot them first.

I cut and welded on hundreds of brand new propane tanks back when I was the only person building these.



http://www.buycorrosionx.com/media/ecom/prodlg/10105.jpg

[Tazza]

Jmorris - is that a sand blasting pot?

I mad a pressure pot out of an old forklift gas bottle, worked very well

[jmorris]

No, you fill them with a corrosion preventative and add pressure to the tank to distribute it. I made 3 different sizes and that was the large one.

The military uses them in conjunction with special probes to prevent corrosion from the inside out on aircraft.

http://www.corrosionx.com/handi-spray.html

[Tazza]

Ahh, that makes sense.

I have small pump up pressure packs that hold a litre for that purpose. I put WD40 or inox in them for corrosion prevention.
Almost like this, only solvent proof (it can handle thinners):
http://www.thegardenparlour.co.uk/shop2/ccdata/images/imageMain_5_22.jpg

[iomskp]

I am also in the LP business in Australia and we dispose of old tanks in much the same way.

[Tazza]

What, shoot them? :P