Homemade Casting pot

[wv109323]

I know several people have made their own casting pot. I was wondering what the expenses involved are? Are you satisfied with your pot? Would you do it again? What are the pitfalls? Is insulation actually needed if casting sessions are kept around 2 hours at a time? Mine is so poorly insulated I question if it is efficient at all.
I have a Lyman 20Lb. that is PID controlled. I just think there could be a lot of improvements in the mold guide and the bottom pour valve. I would like around 30 pounds that would come to casting temperature faster. I am just thinking a larger diameter (than the Lyman) and more shallow would be easier to flux>

[OnceFired]

I bought an old steel pot from Goodwill for a couple bucks. Hard to beat that price, even with home made. That said, if I came across an empty used / damaged propane tank, I'd hit up a buddy to cut it in half for me, and convert to bottom pour. Can't justify buying all the torch equipment etc to cut one tank in half, myself.

[3jimbo3]

I bought an old steel pot from Goodwill for a couple bucks. Hard to beat that price, even with home made. That said, if I came across an empty used / damaged propane tank, I'd hit up a buddy to cut it in half for me, and convert to bottom pour. Can't justify buying all the torch equipment etc to cut one tank in half, myself.

Just curious......how did this work for you? I'm considering the same type of project, I just don't know about the spout.

[dikman]

I think we're talking cross-purposes here. The OP is asking about casting (30 lb. pot), whereas people usually use large pots/propane tanks for melting to make ingots. While it would be possible to make a casting pot out of a propane tank, in my opinion it wouldn't be very practical.

[OnceFired]

Ah yes. I shouldn't read forum posts when I am tired. Or at 1:53AM right now.

Smelting is my steel pot & turkey fryer burner. Casting is my 20lb bottom pour store bought furnace.

[grumman581]

I bought an old steel pot from Goodwill for a couple bucks. Hard to beat that price, even with home made. That said, if I came across an empty used / damaged propane tank, I'd hit up a buddy to cut it in half for me, and convert to bottom pour. Can't justify buying all the torch equipment etc to cut one tank in half, myself.

Actually, a wide shallow pot will result in more surface area for the molten lead and thus more oxidation. You will probably lose more of your alloy that way.

You don't need a cutting torch to cut a 5g / 20-lb propane tank in half. You can do it with a circular saw with an abrasive blade installed. The abrasive blades are currently $2.49 at Harbor Freight, but I've seen them cheaper.

http://www.harborfreight.com/7-inch-cut-off-wheel-for-metal-39679.html

Of course, if you don't have any idea of how to prep the tank before cutting on it, you might want to get someone to help you. What part of Texas do you live in?

[rodsvet]

How about a quick tutorial on prepping before cutting a propane tank.

[kbstenberg]

The stickies already have one.

[grumman581]

How about a quick tutorial on prepping before cutting a propane tank.

Depends upon what sort of tools you have available to you. Here's what works for me:

1. Empty the tank of the pressurized propane. Plug a grill or something into it and let the last bit of gas get out of there.
2. Purge the non-pressurized propane from the tank. This could be accomplished by unscrewing the valve or even drilling a small hole in the tank. If drilling a hole, I use an air powered drill, not an electric. You can then either fill the tank up with water or run an air hose into the tank and flush it with plenty of air. If you had to drill a hole in the tank, you will need to drill another hole for the air to come out and size your hole to whatever air hose size you have available. If you used water, drain it and let it dry out. The water needs to displace all the gas in the tank, so you should fill it all the way up and not just put a little bit in there and swish it around.
3. If you did it right, you can now put a lighter to the hole and nothing should happen. If you didn't get the last bit out, you might get a "whoosh" as the propane burns. This is where Darwin could raise his ugly head. :)

Propane needs a certain percentage of air mixed with it before it will burn (2.2-9.6% propane concentration) (http://www.propanecouncil.org/what-is-propane/facts/). If you have too much air or too much propane, it will not burn. It is actually a pretty safe fuel to work with (especially compared to hydrogen).

[el34]

If you didn't get the last bit out, you might get a "whoosh" as the propane burns. This is where Darwin could raise his ugly head. :)



Live fast, die young, leave a cute widow...

[rodsvet]

Thank you!

[dikman]

Don't sweat it, OnceFired, I think we're all guilty of doing the same at some point (I certainly am!).

Thin cut-off wheel in an angle grinder works well on a propane tank. The hardest part is removing the valve fitting - they are glued in tight!![smilie=b:

[CastingFool]

Live fast, die young, leave a cute widow...

n make sure you have your lead all labeled so we won't have to guess what kind of alloy you left.

[grumman581]

n make sure you have your lead all labeled so we won't have to guess what kind of alloy you left.

You mean that there is another alloy other than "lead"? :)

I also have "linotype", but that's easy to determine since I leave it in the type format and put it directly in my casting pot. No reason to smelt something that is already that uncontaminated.

I've seen welders just cut directly into propane tanks without doing anything more than just emptying the tank. They get a flame jet come out when they pierce the tank, but it burns off quick enough. The flame never gets inside the tank because the propane concentration is too high to support combustion. I prefer to at least flush it with air for awhile. The first time one goes "whoosh" on you kind of gets your attention. Kind of like starting up your gas grill or burner and turning on the gas for too long before you ignite it. Yeah, I have burnt a few hairs from my arms doing that over the years too... :)

[3jimbo3]

Don't sweat it, OnceFired, I think we're all guilty of doing the same at some point (I certainly am!).

Thin cut-off wheel in an angle grinder works well on a propane tank. The hardest part is removing the valve fitting - they are glued in tight!![smilie=b:

A 3 pound hammer does wonders in this area. Get a buddy to hold the tank, position yourself to the
valve so you get a clear shot and let-er-rip. Oh yeah, safety glasses are a good idea here. After a few good swings it will loosen up enough to use a pair of channel-locks to finish up the job.

[el34]

Thank you!

I borrowed that from another esteemed member here, just gotta squint your eyes to see it. Maybe it was a test to see who has the squintiest eyes :grin:.

[grumman581]

I borrowed that from another esteemed member here, just gotta squint your eyes to see it. Maybe it was a test to see who has the squintiest eyes :grin:.

Well, all of us True Texans are "esteemed", it just our nature...

[MrWolf]

I used a plastic dead blow hammer to remove the valve. I had also made a mixture of 50/50 acetone and tranny fluid and let that sit on the threads for a few nights. Actually did that to two tanks, flushed them with water and let sit for awhile. I still need to cut the tanks one of these days..

[Down South]

Cutting propane tanks, I've cut a number of the 250-500 gal tanks to make BBQ pits when I was young. It still makes my exhaust pucker up thinking about it. I always filled them with water but I don't want to ever cut another one.

Oh, on Edit: I would never take a torch to an empty propane tank. The torch can introduce oxygen into the tank. Bad Karma....

[Jon]

A sawzall works pretty well for cutting up a tank. Cutting disks on a grinder get eaten up pretty fast, and a jigsaw is way too slow.

http://i625.photobucket.com/albums/tt332/somephotoguy/Casting/IMG_0147_800x600_zps6b3ba5b7.jpg (http://s625.photobucket.com/user/somephotoguy/media/Casting/IMG_0147_800x600_zps6b3ba5b7.jpg.html)

http://i625.photobucket.com/albums/tt332/somephotoguy/Casting/IMG_0149_800x600_zps1a10a3d4.jpg (http://s625.photobucket.com/user/somephotoguy/media/Casting/IMG_0149_800x600_zps1a10a3d4.jpg.html)

http://i625.photobucket.com/albums/tt332/somephotoguy/Casting/IMG_0157_800x600_zps7e66061a.jpg (http://s625.photobucket.com/user/somephotoguy/media/Casting/IMG_0157_800x600_zps7e66061a.jpg.html)

[double bogey]

I cut the bottom out of a 30# refrigerant 22 tank which I have lots of. Problem is the bottom is rounded, with 4 feet dimpled out and it isn't stable on the burner. I have thought I need to weld a ring around the bottom to fix this, and add handles. Is's been to windy and too cold lately and I have been busy. If you look into this the R410A tanks are twice as thick as the R-22 tanks.

[grumman581]

I cut the bottom out of a 30# refrigerant 22 tank which I have lots of. Problem is the bottom is rounded, with 4 feet dimpled out and it isn't stable on the burner. I have thought I need to weld a ring around the bottom to fix this, and add handles. Is's been to windy and too cold lately and I have been busy. If you look into this the R410A tanks are twice as thick as the R-22 tanks.

Looking at the vapor pressure charts for LPG and R410A, it appears that for a given pressure R410A will definitely have more pressure, thus the tank will have to be stronger (thicker). For the 20-lb LPG tanks, I seem to remember them being good for around 300 or so psi working pressure and quite a bit more for the burst pressure. It looks like the R410A tanks would need an even higher working pressure.

At 110F, propane has a vapor pressure of 197psi and R410A has a vapor pressure of 364psi.

Definitely looks like it has the potential to make a better tank than the 20lb LPG tanks.

[dikman]

Talking to a chap today and he mentioned the LPG tanks used in auto conversions. Besides being bigger, I would assume that they are thicker than a normal LPG tank? He said he may be able to get me a used one, so I said I'll take it if he can. I'm sure I'll find a use for somewhere.