Smelting pot question #2

[Tazlaw]

So consensus says get a propane tank, cut off the top, and use it for smelting pot. Previous question got many responses saying this was the way to go. Hope this question and explanation helps others as well as me!

Ok, I got a 20lb propane tank and cut the top off, above the weld line. I also fabricated (like a kindergartener) some rebar handles. I saved the top and cut small slits along the rim and bent out the tabs, so the top will fit back over the bottom half of tank while smelting. Thought was to trap the heat.

Question—is the bottom ring too tall?, should it be removed?, thus lowering the tank closer to the turkey fryer, which I added additional legs and surface rods to. The bottom ring could be removed and cut in half and put back on, any benefit to that? That is cut in half along the circumference. If I removed the ring it may make the pot unstable-don’t want to go there! I am wondering if I’m losing too much heat with the pot being lifted from the flame. It seems as if the pot were closer to the apex of the flame, it would be hotter. Please advise. Am I over thinking this?

The pot works as is. It smelted about 150 lbs of range lead, but took a long time to get started. At least 90 mins. Once it got going, it went quick. The bottom ring turned red hot so I know my turkey fryer is putting out enough heat-just is there a way to maximize this?



To purge, I opened the valve and depressed the center to let all remaining gas pressure escape-wasn’t much at all. Then removed the valve assembly. Then filled and flushed with water a few times and let it set for 15 mins upside down after the water drained the last time. Passed a blow torch over the top to see if any remaining gas present and there was none. I then proceeded to use cut off wheels on grinder to cut tank into.

Someday I may sandblast it and paint it to make it prettier! Maybe a Ford tractor blue?

[Tazlaw]

Ps. If anyone can tell me how to rotate pictures I’d appreciate it.

[kevin c]

I have a propane tank pot with an intact bottom ring. I'm actually thinking of adding a wider ring to make the base more stable. I also have a high output double jet burner that is rated at over 350K BTU's, but, like you, it took a long time to melt scrap.

There are a few reasons I can think of that can affect melting time. One is that, for any scrap inside the pot, only what touches the inside of the pot gets conductive heat transfer. The scrap inside the outermost scrap only has partial contact with the scrap at the edges and is also slow to heat, and so on into the middle of the pot. Warming scrap by heat radiation from the sides and bottom is also slow because the stuff next to the sides blocks radiation into the interior. This is the reason a lot of casters leave a fair amount of alloy in the pot for the next melt: the molten metal solidifies in intimate and maximum contact with the pot, so it heats faster the next time. Extra scrap or ingots can be put on top of the solid alloy before it melts, allowing it to sink into the metal when it reaches liquidus and then get heated and then melted by being completely immersed in molten metal. This creates a bit of a problem though if you want to mix an alloy different from what's in the pot.

Another problem is the range scrap. It often contains a lot of debris like dirt, sand and gravel that acts as insulation, dramatically increasing the time and amount of heat needed to melt the lead.

But, besides all that, probably the best things to do are blocking wind and insulating the pot. Any wind at all is going to blow heat away from the pot, so a good wind screen will probably make a bigger difference than lowering your pot one or two inches. You can put the screen around your work area, but it'll probably work best being around burner, shielding the area from burner level up to pot level.

The sides of the pot can be insulated to hold a lot more heat in the pot. I use a sandwich of sheet metal bent around the pot, filled with fiberglass insulation (others use rock wool which is rated to higher temperatures). It sits on top of the burner's pot support and isn't attached, making the pot easier to pick up with vise grips when necessary.

Those last two things made the biggest difference for me. The first issues I deal with by adding a lot more BTU's with a weed burner.

[kevin c]

And I basically gave up trying to rotate pictures. I find it usually works if I shoot in landscape orientation (image wider than tall).

[fivegunner]

Nice pictures anyway, looks like you have a nice lead pot .

[Mal Paso]

I left the bottom ring for stability but added a wind screen. I bought a long handle 4 inch diameter stainless frying strainer from Smart and Final restaurant supply for $4 and roll the jackets against the side. As the lead melts out the jackets rise to the top and can be removed.

[Hossfly]

I haven’t melted any range scrap, yet because I’m still filling my berms with lead alloy. So when i melt ww it takes about 30 mins. At 150# with some melt in bottom from last time. Wind shield helps a lot. Insulating upper part of pot with (kaowool) helps also, and put lid on check @ 30 min. Put top back on. Cut a few slots in base ring will give heat a chance to sort of flow better, getting flame closer will also help with btu efficiency. Good luck, be safe, and remember every thing is hot all the time when dealing with 750’ alloy. Wear your safety gear.

[Wild Bill 7]

I made 2 propane melting pots and made a wind screen for both with the other half of the pots. My Bayou burner is 185,000 BTU's. It works very good but it does take more time to melt from scratch. I also made lids for both with home made handles from a scale cover from work. I do need to brace the burner frame for safety sake. I have a friend that is going to help me on that part since I don't have welding skills of any kind. I'm using bricks for bracing for now because the that's a lot of weight in the pot.

[Tazlaw]

Here is my turkey fryer. I left it stock but added three more legs and three more pot support arms. It appears very sturdy. I had 150lbs in the pot and was able to pretty aggressively stir the pot without tumping it over. Yes tumping is a word !

[lightman]

Nice looking set up. I have not been able to find you a propane tank so I'm glad to see that you were able to locate one.

[Tazlaw]

Nice looking set up. I have not been able to find you a propane tank so I'm glad to see that you were able to locate one.

Thank you for looking. This one only cost me $10. Now for metal to make a wind screen/insulator.

[sukivel]

Thank you for looking. This one only cost me $10. Now for metal to make a wind screen/insulator.

Have you thought about making it a bottom pour? I’ve decided I need to do this, but I want a bottom pour.


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[Cheeto303]

I love this forum, so many geniuses.

[Mike W1]

Ps. If anyone can tell me how to rotate pictures I’d appreciate it.

Save the picture to your desktop and open that with MS Paint. There's an option to rotate the picture and then save that one.

[Tazlaw]

Have you thought about making it a bottom pour? I’ve decided I need to do this, but I want a bottom pour.


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How would I make it a bottom pour? Are you talking the propane tank? I suppose one could weld a piece to the bottom and drill it, lap it, and find/make a rod to go into it. Have you done this? Please add pics. Thanks.

[sukivel]

How would I make it a bottom pour? Are you talking the propane tank? I suppose one could weld a piece to the bottom and drill it, lap it, and find/make a rod to go into it. Have you done this? Please add pics. Thanks.

No I am wanting to make a bottom pour with a propane tank. I have seen a few on the internet but I am concerned with lead solidifying at the ball valve (if I go that way)

I have found several videos on YouTube and the solidifying doesn’t seem a problem. I even found a few wood fired smelters...


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[44magLeo]

I was thinking of cutting up into the bottom ring part way at each support on my burner, this way when you set the pot on the burner the cuts slip down over the supports. If done right the bottom of the tank will be jst a bit above the supports. Don't want the bottom touching, might make it tippy.
I have thought about making a bottom pour out of a propane tank. To do so I would cut the tank off very near the bottom. Just where it starts to curl under from the straight side. Cut the top off the same way, Just as it curls in. This will give me a straight tube.
Get a piece of 3/16 or 1/4 inch flat steel cut in a square a bit bigger than the tank. Then use angle iron to make legs. Weld the angles on at the corners of the flat steel and at the upper edge of the tank. The legs will angle outward for stability. Then angles across the bottom of legs so it won't sink into the ground.
Once this is done weld a bung on the bottom of the tank near the edge between two of the legs. This bung will become the pour spout. Up top build an arm similar to the way Lyman has on their electric pots to open and close the valve. The valve it self is a piece of steel rod with a rounded point to match the hole in the bung. I would even put an adjustable stop on the handle to control flow. The hole in the bung and the end of the rod will be made like most bottom pour spouts. The end of rod would go down into a large hole with a smaller opening in the bottom. This way the rod can't come out of the hole and let the contents of the pot run out.
With it's own legs I could modify my burner so it sets the right height to set under the pot. The burn would not support the weight of the pot.
I could even use an electrical heating element like a stove top burner has. I've looked at these burners at Lowe's The 8 inch with 6 turns of the element is 2350 watts on 240 volts. With a slight alteration of my PID, A 240 volt relay instead of a 110.
I have a Harbor Freight weed burner. Don't recall BTU's but I could use that to start the melt by just aiming it down into the top of the pot. Once it get melted the electric can control the temp.
Close to me is a Steel Supplier. They also make custom thing out of steel. They have a place in back where they put scrap and odd pieces left over from this custom jobs.
I was down there one day and in the scrap box was a 14 or 16 inch square of 3/8 inch thick stainless steel welded to the end of a piece of 3/8 wall 12 inch diameter stainless steel pipe about 6 inches long. The plate had 4 elongated holes, likely for adjustment purposes. I almost took it home. But welding the holes up and getting the pipe welded all the way around so it wouldn't leak was a bit more than I wanted to deal with.
I might just find out if they could build me the kind of pot I described earlier. My welding skills are not that great.
I guess I'll have to
Leo ask sometime.