Smelting pot question

[Tazlaw]

Hey all!
I have a chance to buy a rather large cast iron pot. 21” wide, 14” deep. I can possibly get it for $45. BUT IT HAS A LARGE CRACK. I can weld a little and could possibly fix it. I currently have a range berm that I can mine my lead from. I wouldn’t really NEED the pot but it would be better than mine. I can only do about 50lbs at a time with the pot I have.

Any thoughts?
Repair ideas?

[Dapaki]

I have been welding professionally for 30 years and I have yet to see cast iron welded that did not crystallize and break. You really need to braze the crack (TIG or Gas) with 77-Electrode (my fav) or another high heat brazing rod.

Keep in mind that cracks in cast iron are very hard to see at times and pots will hold water without leaking when cold. I like to warm the pot up on a stove and hit the inside with a thin oil like WD-40 or similar. The oil will show you the end of the crack.

Use a small drill such as a #60 or 1/16" bit and drill a hole just past the end of the crack or it WILL be coming back!

As far as paying $45.00 for a broken pot? It should be free to you, there is no way I would purchase it as a good dutch oven at Goodwill will run about $10.00 in good shape.

Good luck, this will be a learning experience for you!

[kevin c]

A pot that size with cylindrical walls has a theoretical capacity of over 850# of lead. A few questions worth considering:

Are you ever going to process that amount at one time?

Do you have a stand that can bear the weight?

Do you have a heat source that will melt that much lead?

Do you have ingot molds and ladles to match that capacity?

How are you going to get lead out of the lower half of the pot? In ladles big enough to deal with that capacity, say a Rowell #5, the bowl top is in the same plane as the handle; dipping at an angle with that set up gets very little fill, and a ladle with an angle still won't get the bottom couple inches unless very small and shallow - an exercise in frustration (and if you leave the last couple inches in the pot during storage you're talking about moving around 120+ pounds of lead plus the weight of the pot).

To get all the lead out, are you going to make it a bottom pour? Do you have the fabrication skills available?

And perhaps most pertinent, are you willing to stand in front of (or, with a bottom pour, almost under) a cracked pot filled with 800# of molten lead, repaired or not?

[Winger Ed.]

I'd pass on that deal.

[redhawk0]

I'd pass too. IF that weld doesn't hold...you could be looking a some pretty serious burns when it lets loose full of molten lead.

Get a propane tank and cut it in half. It will hold over 200 lbs....its certainly enough.

redhawk

[ReloaderFred]

A cracked cast iron pot is only good for display purposes, such as an antique display. If cast iron was easily repaired, they would have fixed the Liberty Bell.

I use cut off propane tanks for smelting, and they work about the best of anything I've tried, so far. Just shoot a few holes in the top half with something powerful enough to go through it, let it air out for a day or so, and then cut it off at the weld.

Hope this helps.

Fred

[Tazlaw]

Thanks guys. You have talked me out of it. That’s why I like this group. Safety first.

[Hossfly]

Old discarded Freon tanks work also they wont blow up but do give off bad gas when cut with torch, you’ll need to cut with a saw.

[country gent]

Cast Iron is tricky and requires some special techniques to weld. Pre heat, finding ALL the cracks and drilling small holes at each end, veeing out for the filler.slow cooling, Then when all done you still arnt sure you got all the cracks and how well they are filled.

I will also suggest you pick up an out of date 25lb propane cylinder. pull the valve and wash out several time with soap water. Then run an air hose down in and let it run for awhile. When done cut the top off carefully. Tanks barrels are dangerous to cut so be very careful. I mark the tank where I want the cut and 2 wraps of masking tape around tank make sure the tape lays flat with no wrinkles and ends meet even. this gives a true cut mark all the way around I use a hand hacksaw and cut around following the tape line. A long 3/4" pipe nipple in the valve thread allows it to be held in a vise.

[nccaster77]

Cast Iron is tricky and requires some special techniques to weld. Pre heat, finding ALL the cracks and drilling small holes at each end, veeing out for the filler.slow cooling, Then when all done you still arnt sure you got all the cracks and how well they are filled.

I will also suggest you pick up an out of date 25lb propane cylinder. pull the valve and wash out several time with soap water. Then run an air hose down in and let it run for awhile. When done cut the top off carefully. Tanks barrels are dangerous to cut so be very careful. I mark the tank where I want the cut and 2 wraps of masking tape around tank make sure the tape lays flat with no wrinkles and ends meet even. this gives a true cut mark all the way around I use a hand hacksaw and cut around following the tape line. A long 3/4" pipe nipple in the valve thread allows it to be held in a vise.

I use an old regulator. Cut off the hose. Open up the valve all the way to purge any remaining lpg and cut with my angle grinder right along the weld. No problems in many cut tanks for various purposes. Tank should be “empty” of course.��

[poppy42]

I would not shy away from a $45 broken cast iron pot, I WOULD RUN! Fast and far. As dapaki posted welding cast iron it’s definitely not for an inexperienced welder! And I certainly would not pay $45 for a broken cast-iron pot ! I have welded cast-iron with about a 45% success rate. You would be much better served by finding an old 20 pound propane tank flush it out and cut it in half

[Chill Wills]

Who ever came up with the steel propane tank, likely more than one person, had a great idea. It is the cheap, strong, safe way to go for home rendering amounts.

For very little money I came up with this after my second cast iron pot in 35 years failed using a plumbers floor furnace.
I put a bail and a small angle-iron tab on it so the last 25 lbs can be poured out. I can melt 200 plus pounds at a time but 150-175 is more comfortable.

[NyFirefighter357]

https://www.agrisupply.com/wash-stew-pots/c/6200020/

[jdfoxinc]

The liberty bell is bronze.

[lightman]

I think you are wise to pass on that pot. I've seen some pretty good welders weld cast iron and it eventually cracks again. A cut off propane tank works well. If you are a decent welder you can make one from a large piece of pipe and a piece of steel plate. Wider is easier to use than deeper. I might be able to find a piece of pipe if you want to go that route. I also saw a propane tank in someones scrap pile the other day that I could ask about.

[Dapaki]

A cracked cast iron pot is only good for display purposes, such as an antique display. If cast iron was easily repaired, they would have fixed the Liberty Bell.

I use cut off propane tanks for smelting, and they work about the best of anything I've tried, so far. Just shoot a few holes in the top half with something powerful enough to go through it, let it air out for a day or so, and then cut it off at the weld.

Hope this helps.

Fred

(Pssst! The Liberty Bell is a type of bronze, 70% copper and 25% tin, with the remainder consisting of lead, zinc, arsenic, gold and silver.)

[ReloaderFred]

I stand corrected. I'm old, but I'm not old enough to have been there when it was cast.......:drinks:

[Conditor22]

https://www.harborfreight.com/12-inch-cast-iron-dutch-oven-44705.html

[redhawk0]

An old propane tank is perfectly safe to use a cutoff wheel on....but ONLY after you've purged it.

Remove the top valve safety cage first (a 3 lb hammer will break the welds)...then use a wrench and same hammer to unscrew the valve from the tank...now fill it with water and turn it upside-down to drain...do this 3-4 times....pass a match over the hole if you want...to test that all gas is removed. (my match didn't even flicker)

Now cut it in half just ABOVE the weld line with a diamond cut-off wheel....and affix a handle if you want.

Its pretty simple...and if you go to a propane fill station...you can likely get an old outdated tank for free.

[EDIT] - I did start a post on my "first caldron"....I took a few weeks to let it purge...I was later corrected that it doesn't need to take that long...once full of water...the gas is displaced.......just an FYI...in case you run across that post.

redhawk

[ReloaderFred]

An old propane tank is perfectly safe to use a cutoff wheel on....but ONLY after you've purged it.

Remove the top valve safety cage first (a 3 lb hammer will break the welds)...then use a wrench and same hammer to unscrew the valve from the tank...now fill it with water and turn it upside-down to drain...do this 3-4 times....pass a match over the hole if you want...to test that all gas is removed. (my match didn't even flicker)

Now cut it in half just ABOVE the weld line with a diamond cut-off wheel....and affix a handle if you want.

Its pretty simple...and if you go to a propane fill station...you can likely get an old outdated tank for free.

[EDIT] - I did start a post on my "first caldron"....I took a few weeks to let it purge...I was later corrected that it doesn't need to take that long...once full of water...the gas is displaced.......just an FYI...in case you run across that post.

redhawk

I find it more fun to shoot a few holes in the top half to let it vent......:drinks::Fire:

[44magLeo]

The place I get my propane tanks filled had old tanks setting around. I asked about getting one to cut up. They said sure and even pulled the valve for me. Didn't even charge me for it.
Once home I flushed it with the water hose a couple times then set it up side down to drain. Propane is heavier than air so it drains out.
After a few days I cut it off with the cutoff wheels I use on my 4.5 inch angle grinder. One of the best tools I ever bought.
I had the propane burner I got years ago for family cook outs to fry fish, cook corn on the cob and such stuff.
Part of what I cut of the top I plan on getting welded around the bottom so it has a larger foot print to be more stable on the burner.
Need to finish that up I guess.
Leo

[Cast_outlaw]

I cut up a 30lber for a wood stove. Rinsed it a couple times, then filled with water to the weld, passed a torch over the hole where the valve was. burning off the remaining gas, witch jetted out the hole, then cut off with plasma cutter or cut off wheels. If your in a hurry this works

[Dragonheart]

I have TIC welded cast iron many times, so if you just want it stuck together I can do that. However, if you want it not to leak that's another story. Problem is cast iron has a lot of impurities that contaminate the weld creating small holes and voids.

I would suggest cutting the top off a discarded propane tank. I did this one about 8 years ago and it has melted down hundreds of pounds of range scrap.
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