Brass gate valve on lead melter

[stovepipe699]

I’m planning a lead melter using a repurposed 20 lb propane tank and I’ve seen some YouTube videos where people used an external “all metal” gate valve. Has anyone here been down this road before? I found this brass valve at the hardware store, with a brass gate that raises and lowers. Is this what folks use? It still has a rubber packing around the stem, is this the right type of valve? I could remove it and I doubt it would matter since the lead isn’t under pressure, but I’m not sure if there’s any other parts in it that would cause issues.

[Winger Ed.]

Should work.

The packing is to hold water or steam pressure from leaking.
I'd think Lead with no more pressure than gravity would be too thick in viscosity to get past it.
If it does, it could be replaced with fiberglass shreds or wool like 'Pink Panther' or something that will take the heat better.

Also, the handle on it is going to be some kind of hot!
Maybe vice grips on the stem might do OK.

[stovepipe699]

Should work.

The packing is to hold water or steam pressure from leaking.
I'd think Lead with no more pressure than gravity would be too thick in viscosity to get past it.
If it does, it could be replaced with fiberglass shreds or wool like 'Pink Panther' or something that will take the heat better.

Also, the handle on it is going to be some kind of hot!
Maybe vice grips on the stem might do OK.

I never thought of fibreglass wool insulation, great idea! No doubt the handle will be hot, welding gloves should help, I can always make a custom handle or vice grips like you suggested.

[Winger Ed.]

I never thought of fibreglass wool insulation, .

Yeah,,,, in the old days you could grab a tuft of Asbestos and stick in there.
But,,, ya gotta take what's left

If anything- a little pinch of pink panther from the attic should do fine.
When the gate is closed, or all the way open, it won't want to leak anyway.

[Bantou]

My concern with brass is that it contains zinc. I almost went with a similar set up for mine but I worried about the zinc leaching into my lead.


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[William Yanda]

"replaced with fiberglass shreds or wool" Winger Ed

Or maybe graphited string from the plumbing dept.

[William Yanda]

My concern with brass is that it contains zinc. I almost went with a similar set up for mine but I worried about the zinc leaching into my lead.


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I can't see how the zinc would leach at molten lead temps. Compared to the quantity of lead involved in a melter made from a repurposed propane tank, I suspect it would be miniscule. Zinc in very low quantities allegedly does not cause problems.
respectfully,

[Bantou]

I can't see how the zinc would leach at molten lead temps. Compared to the quantity of lead involved in a melter made from a repurposed propane tank, I suspect it would be miniscule. Zinc in very low quantities allegedly does not cause problems.
respectfully,

I have no idea if it would or not. I sell the majority of the lead that I melt and I didn’t want to take the risk.


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[frkelly74]

I have seen brass valves dissolve in water over a period of time. Granted, They were cheap Menards , made in China valves but over time they stopped shutting the water off and when I took them apart the insides were eaten away, gone. I do not think that they will hold up under molten lead temperatures, I would not trust them, personally.

[Mr Peabody]

Good chance it will get hot and gall.

[country gent]

Also a good chance at molten lead temps that it will leak do to expansion of the parts when up to 700*. Another ossue will be ots going to be lower to operate than the normal style valves. On big ingots wont be a big problem but smaller over fill runs will happen.

[CastingFool]

A gate valve would be slow to open, IMO, a solid brass valve like those used strictly for gas service would work better. It's like a ball valve but without the teflon packing. You still would need something to open it and close it, as it would get hot.

[Texas by God]

Gate valves are designed to be left open or left closed. Constant use will wear the gate and allow seepage to occur. I fear molten lead will wreck one outright.

[Scrounge]

I have seen brass valves dissolve in water over a period of time. Granted, They were cheap Menards , made in China valves but over time they stopped shutting the water off and when I took them apart the insides were eaten away, gone. I do not think that they will hold up under molten lead temperatures, I would not trust them, personally.

Water, particularly hot water under pressure, is referred to as the "universal solvent" for a reason. Quartz crystals and opal are silicon dioxide that was dissolved in water and came out as the water cooled. Even good brands of brass valves will erode over time when you run hot water through them. Molten lead probably won't help them, but if you must use brass, get valves that are steam rated. You can also get stainless steel valves. You don't want to look at the prices. Though you can probably replace several good quality brass valves for the cost of one in stainless. Been working on a boiler and equipment that uses hot water & steam for much of the past 5 years.

Bill

[AggieEE]

If the brass is clean enough for the lead to "Tin" the brass, the lead will eventually dissolve the brass. Burned up a lot of copper soldering tips in high school shop class. Since brass is mainly copper/zinc alloy the tinning you see on a soldered piece of wire or brass is an inter-metallic compound of the copper and the tin/lead solder. So, if you can solder it the solder will dissolve it. Stainless steel would be a good choice or, I don't know if they make black iron valves, a black iron valve with a good blue on the parts. The iron oxide should prevent the lead from sticking to it. My $0.02.

[bangerjim]

I have been engineering and selling industrial control valves for a living for the past 40 years thru my engineering firm. A hot water gate valve will NOT hold up in molten Pb service!!!!!!!

No way.....NO HOW!

1st - the rubber packing in a standard off-the-shelf big box store valve is good for around 300F max. Hot water is a lot cooler than HOT LEAD!!!!!!! These things are hot water valves...not molten Pb valves!!!!!!!!! OMG!

2nd: You need metal to metal seats that are lapped so there is a good seal. And packing/elastomers that will take at least 850F. The only thing that will take those temps is Grafoil packing in industrial control valves.

3rd: If I were to work up a valve for your molten Pb service, it would run you around $1,200-$1,400 or more. You are no talking Home Depot stuff here, my friend! A temperature of 800F rated valve's construction is VERY expensive. Some of the high pressure high/temp steam valves I sell to power plants are $4,000 to $5,000 EACH and that is not with a pneumatic actuator!

4th: And you want all 316SST construction (NOT any brass!) so the Pb will not stick to it.

5th: And since Pb cools very rapidly outside the pot, you will have to heat-trace (with a flame)the valve to prevent the Pb from hardening inside it. And YES......it will! I have to hit the nozzle of my Lee bottom pour with a propane torch sometimes to "un-thaw" it! And that is a tiny little valve right under the heat source. Think about having that larger valve away from the heat source.

Your instance here will have to take some serious thinking and planning.

Sometimes the simplest solutions ( example: the valve on a Lee bottom pour!) are the best.

Good luck with your venture.

bangerjim

[GregLaROCHE]

For the packing, maybe gasket material for wood burning stoves. It comes in all sizes.

[gpidaho]

I'd just buy a large ladle and be done with it. Brass valves seem like a accident waiting to happen. Gp

[jaguarxk120]

What bangerjim has said is so very true.
Valves for high pressure steam service 1200 pounds and above require
special packing. Steam pressure at 1200 lb. super heated at 900 degree's
will melt a pot of lead in no time at all!!!

[BeeMan]

Brass gate valve with water service packing - not good at all. What bangerjim said.

I made a large Lee pot style valve in a similar sized pot to your intent. It worked as designed- for a while. Dirty lead and debris will inevitably result in leaks. It's just less trouble to use a ladle to fill ingot molds once the melt is ready to pour.