Building Bottom Pour Smelting Pot

[jeepvet]

I am building a bottom pour smelting pot from a 20# propane tank. I have searched this forum and gotten some great ideas and designs. I have in my head that mine will incorporate many of these designs but be unique in many ways.

My question (to the more informed than I) is about galvanized bolts in the valve. I can not find any bolts that will do what I am planning that are not galvanized. Will there be enough zinc or other contaminates to ruin the lead? Is this even something I should be concerned with because I do not think that the galvanizing will be effected by the relative low temp of the lead?

I am fairly computer illiterate but will try to figure out how to get some pictures of my pot posted when I am done with it. Assuming it works and does not end up in the junk iron pile beside some of my previous projects.

[BACKTOSHOOTING]

From what I have read here a small amount of Zink will not hurt. Up to 1% or 2% and you are not going to get near that from the bolts if any.

[country gent]

You can burn the galvanized coating off with a tourch but be outside and up wind side of work as Galvanized coating give off a poisonous gas when heated or welded.

[MattOrgan]

If you have a cutting torch, just burn the galvanizing off with the torch ( don't breath the fumes or you'll have diarrhea like you've probably never had). Any residue easy brushes off.


What at gent said while I was typing!

[Yodogsandman]

If you feel that you've been exposed to the galvanized metal fumes, drink lots of milk. My dad used to weld on the job and always told us that.

[Faret]

Only 20# that ain't big enough!

[jeepvet]

Thanks. Just didn't know if it would shed enough zinc to be a problem. My dad and I have both welded and cut LOTS of galvanized pipe and diarrhea is the least of your worries breathing the smoke. It will also give you a bad, hacking cough that will last for quite some time. Drinking milk will help some, but the best thing to do is avoid it if you can.

Thought about the cutting torch but I am out of oxygen and they say my bottle is out of date and will not fill it.

Ok Faret, joke, joke (and that is how I am taking it, as a very funny joke). You are dead on right, 20# is not near enough lead. But this is one of those bottles that holds 20# of propane. Should hold 100+ #'s of lead, if not I will have wasted a lot of time, again.

Ok, honing up my engineering skills and going for it. Wooo, Wooo!

[crawfobj]

Please keep us posted!

[dikman]

Half a 20 lb. propane tank will hold about 150 lbs. of molten lead (with a bit of headspace to allow for stirring). Should be a nice little project, have fun.

[William Yanda]

If you can use 3/8-16 bolts, I have access to quantities of stainless hardware. Let me know what you need and I would be glad to offer them on a PIF basis. Although the amount of zinc that would enter your melt from the coating on hardware would probably get lost so quickly as to not be noticeable.
Bill

[jmorris]

I built a 7" diameter pot that will hold more than 60lbs, that I used to smelt with before I decided to use it as the pot for my casting machine.

I didn't convert it to bottom pour until it became part of the casting machine. You can still see the trunnions and what is left of the pour spout.

[country gent]

Another quick thought is if the bolts arnt in the melt and even a few inches above it then they may never reach a temp to become an issue. Up in the open air a few inches above the pot they may lose enough heat to stay intact. A mould casting with the full temp lead only gets to around 400*-450*. The linkage above the pot may be along the same.

[Horseman1]

If the galvanized bolts bother you, you can do this.

I'm no chemist nor am I a pro welder, but when I want to weld on some galvanized pipe I dip the end in HCL to get rid of the zinc.

Throw the bolts in muriatic acid and leave for a while. When it stops producing hydrogen bubbles, the zinc is gone. Take out the bolts (careful, that's acid and zinc chloride) and put them in a baking soda and water solution to neutralize the acid. Add more soda as required until it stops producing Co2 bubbles. The leftover is hcl and zinc chloride which can be neutralized by slowly dumping it into water and soda.

Rinse the bolts off with water.

Dont breath the fumes and the usual safety disclaimers apply....

H1

[jeepvet]

Thanks for all of the ideas for getting rid of the galvanizing. But if it will not cause a problem, I think I will just be lazy and leave it. I will post pics and commentary when it is finished. Might be a little while, my life is pretty full right now and my wife has put my pot on the back burner, so to speak.

[gwpercle]

Be careful with a large bottom pour. 150 lbs. of molten lead is going to come out with a good head of steam, so be careful when you pull the plug. I can just see a molten stream shooting out.
Good Luck....Gary

[ffries61]

Granted a propane bottle smelter will be deeper than say a RCBS Pro-melt, the volume of the lead has no bearing on the pressure, the heighth of the column of a fluid determines the pressure, I'm working on a similar project myself. I'm making a tapered plug for the orifice though, to hopefully have some control over pour rate.

Fred

[fordfan]

I built a bottom pour smelting pot out of a 20 pound propane tank it holds a lot of melted lead

[JSnover]

Even if the zinc melts off and gets into the lead, so what? It will be a minuscule amount even if you're only working a twenty pound batch and it will only happen once. Skim it off and forget about it.

[jeepvet]

Finally got some time to work on the smelting pot today. Sorry the pictures are so small but I had problems even getting these on here.

25 # propane tank cut about 3" below seam with bottom ring and top handle removed. I will not fill this even close to the top but I wanted plenty of slop room.


2 - 3/4" street elbows and a 6" pipe nipple screwed into fitting where valve was removed from top of tank.


4" X 1/8" flat strap bent in 10" diameter circle welded on bottom with cut out for plumbing and 1 1/2" X 1/8" flat strap around top to seal heat in while heating. Original handle welded on top. Should raise some eyebrows when someone sees a propane tank sitting on top of a burning fish fryer.

Still working out the kinks in the valve system. Trying to figure out how much water leakage is allowable before lead leakage will occur. Right now it only leaks about a 5 drop string every 5 - 10 seconds or so with about 1/2 - 3/4 gallon of water in tank. In the process of lapping the valve into the bottom of the tank fitting but the drill battery died.

Will post more pictures as the project progresses.

More suggestions or problems seen? All help is greatly appreciated.

[Three44s]

Just as you found "black iron pipe" there are black iron bolts. You can find them.

But as earlier noted ...... you can burn off the galvenized coating with caution or just let it go as it's a very small amount compared to the amount of lead you'll be containing in your converted lead pot.

Best regards

Three 44s