Idea for leaking pots

[Drew P]

Over the years it’s become evident that the number one compliant among lead meters is leaking bottom pour spouts. I understand they are all a needle type valve metal on metal. What I’m wondering is if there is another material that could be used to stop leaks that will hold up in that temp environment. At 750° there are rated plastics and rubbers that “should” hold up but has anyone actually tried this?

[Winger Ed.]

The problem is usually crud getting on the needle between it and the seat.
Changing the material of one or the other contact points really wouldn't change, or keep stuff from getting between them.

[bangerjim]

No elastomeric material will prevent crud buildup and leaks. The crud will just get in-bedded in the seals.

Just clean your pot out very regularly and lap the valve that's in it if VERY leaky.

As to temps, the only thing that will survive 800F is the Grafoil packing we use in our series of very high temp industrial control valves. And it is very sensitive to grit and dirt! Valve stems and packing boxes are clean, not with melted lead crud in them.

Just do what we all do: CLEAN YOUR POT!!!!! I have 3ea) LEE 4-20 bottom pours and they do not leak because I maintain them.

banger

[Conditor22]

I recently aquired an old RCBS Pro-Melt at a price I couldn't pass on. The first thing I discovered is the pour/drain spout in much thicker than Lee's. I'm wondering IF the lead is cooling in the Lee spout and causing "drip-o-matic" problems along with/possible dirty alloy. (I flux all my alloy 4 times when smelting) so I'm pretty sure everything that goes in my pot is clean. Haven't had a drip yet from the old pro melt.

we've taken the 4-20 apart and polished the valve stem and seat, helps for a while, we've added weight to the valve stem assembly, helps for a while. -- makes me wonder if it's not just dirt in the spout

My 2¢

[Winger Ed.]

. -- makes me wonder if it's not just dirt in the spout

Probably so.

I had a Lee pot years ago, and it had the usual issues.
It had a screw driver slot on top of the needle and you could push down and turn it back & forth.
That helped a lot and put off more serious cleaning.

I figure it was just dirt in it too. Stirring down deep and scraping the bottom with a big screw driver helped too.
If you could dislodge the dirt & crud, it wanted to float up.

[Bazoo]

I solved the problem by switching to ladle pouring exclusively. I got tired of pleading with the pot to work right.

[TjB101]

It had a screw driver slot on top of the needle and you could push down and turn it back & forth.
That helped a lot and put off more serious cleaning.

That does help ... I always leave a solid inch of lead in the pot when I turn it off. This also seems to help.

[Winger Ed.]

That does help ... I always leave a solid inch of lead in the pot when I turn it off. This also seems to help.

Me too, I leave my old pro-melt about 1/3 to 1/2 full all the time.
I think when it gets down real low, its kind of hard on the heating element, as if it doesn't know when to shut off.
Maybe it doesn't matter, but I feel better about it.

[JonB_in_Glencoe]

Obviously as already said, keep your pot clean, so crud can't get lodged in the valve/seat area.

But let me add these thoughts:
The pot valve is usually steel. Steel is less dense than Lead. Steel will float on molten Lead.
with that said, Weight is your friend, add weight to the valve.

[popper]

Get a cheap tap handle, fasten to top of rod - pour - if drip, glove hand can turn it a bit and stop the drip.

[Ed_Shot]

Get a cheap tap handle, fasten to top of rod - pour - if drip, glove hand can turn it a bit and stop the drip.

Exactly what I do with my Lee 4-20 except I just use a screw driver. It solves the problem and doesn't need to be done often. I've thought about putting a knob on top of the rod.

[slim1836]

The problem is usually crud getting on the needle between it and the seat.
Changing the material of one or the other contact points really wouldn't change, or keep stuff from getting between them.

I did the same along with hanging a lead weight on the handle.

Slim

[NyFirefighter357]

I have 2 Lee pots, I don't use them much as I haven't done much casting. I will say I keep a torch close by to heat up the nozzle when the flow slows. It's for sure crud build up that causes most of the leak, I clean my spout with a deep "V" wire from the outside in & also use the screw drive to move the valve. I also replaced the handle with a 16oz egg sinker which helped a lot. I just rebuilt my Lee 10lb pots but haven't run much through either yet. I also hear if you open the hole on the nozzle a little it helps prevent crud build up. I also keep something under my pots to catch any drip.

[Drew P]

Well crud doesn’t explain why some models drip less than, okay, the Lee pot lol. On my Lee I took it a step further and replace the rod with a longer quarter inch rod that I sharpened myself and placed a large weight on top of. I can spin the weight freely to stop drips which works, but I have to use it a lot.

[Petrol & Powder]

I think it has all been said.
The material the valve is made from is probably not that critical. Changing to some super hard steel or ceramic isn't the solution.
A clean pot, weight holding the valve shut and reasonably good finish on the needle & seat will get the job done.

[OS OK]

I think that 'crud or dirt' everyone speaks of is actually 'oxidized bullet metal' being drawn down in the mix when the sprues go back in the pot. Depending on how well you re-prep the next pot fill, stirring/scraping, skimming a little, maybe 1/3 teaspoon of oxidized metal that does not stir back into the melt and capping off the melt with a wax covering to prevent more oxidation as you cast.
If your using anything other than the wax to cover the melt, ie. 'sawdust'...your inviting foreign material to wedge between the valve body and stem.

If you throw the sprues back in as you cast, you should have an indication of this oxidized bullet metal showing up in the cast...little unexplainable inclusions in an otherwise perfect cast. You'd not notice them if they are within the cast body but if they end up against the mould cavity, they'll identify themselves.

Being able to quickly press against the valve as you turn the stem helps a lot, having that torch ready to clear the valve helps too, having a bent wire to push up inside the spout as you flush a little lead out helps also...in the end I think these little problems probably plague all of us regardless of our methods.

I still get drips but not from the lack of effort to minimize them...



Here's an example of what I call inclusions...this one is extreme but it's the same basic bumpy not smooth cast that should be perfect coming from a clean cavity without any oils that have gotten in the cavity, without any sawdust, without excessive smoking...just this metal that looks to me like it was oxidized metal that didn't stir out of the melt...it happens & I usually see it in much smaller detail than this.



You can get 'stuff' in the valve to by tilting the pot and trying to pour out all of a remaining batch of lead into small ingots for later use...I do this with my 'ratio-lead' like 30:1, so I have it to mix in with another batch of the same. Here I was my own worst enemy...now I use welding gloves and physically pick the pot up and pour into a small ingot tray without going throuth the valve...this remaining oxidized metal will mostly end up on top of the ingot anyway but that's a matter for using it again in another pot another day...for now it's back in stock lead and ready & identified.



If you use the wax, parraffin or candle, you can light it off and it'll barely be noticeable giving off any smoke...hahaaa...if not, better have a good fan running at high speed making a draft in the shop!



I still get leaks from time to time but it ain't because I didn't at least 'try to minimize them'...I haven't seen anyone yet cast without little on-going & re-occuring little problems that have to be attended to...casting ain't exactly a 'squeaky clean' operation...

[onelight]

I do it the same way I never drain the last inch through the valve , I pick up the pot and pour it over the side into my ingot mold . Most of the trash floats on top no need to run it through the valve.

[Mal Paso]

The first time I cleaned my pot I was surprised to find grey powder under the lead. In spite of the powder being lighter, Surface Tension was holding it on the bottom of the pot. Stirring does not seem to eliminate the problem.

I have also found what I think were lead oxides stuck to the valve needle.

As distasteful as it seems I think we're stuck with cleaning house every once in a while. LOL

[country gent]

The high temp plastics will be much lighter than the steel and increase the floating issue. Adding a heavier knob to the handle helps some but isnt a cure all. I always wondered about a carbide rod as weight would be increased some, but it would be a pain to make and maintain. On the older lee pots the rod also runs at an angle to the spout and seat Not a real good set up, the new pots are straight up and down much better.Increasing Dia at the bottom and seat size might help some but dirt or dross in the mated surfaces will still hold it open. One thing that does help on leaking pots that are clean is to lap the seats together with progressively finer compounds. I have done several of the older 10 lbers over the years and they were much better. This needs to be to be done carefully as it needs to be held straight and true. Its lapped in like a auto valve

[Drew P]

The high temp plastics will be much lighter than the steel and increase the floating issue. Adding a heavier knob to the handle helps some but isnt a cure all. I always wondered about a carbide rod as weight would be increased some, but it would be a pain to make and maintain. On the older lee pots the rod also runs at an angle to the spout and seat Not a real good set up, the new pots are straight up and down much better.Increasing Dia at the bottom and seat size might help some but dirt or dross in the mated surfaces will still hold it open. One thing that does help on leaking pots that are clean is to lap the seats together with progressively finer compounds. I have done several of the older 10 lbers over the years and they were much better. This needs to be to be done carefully as it needs to be held straight and true. Its lapped in like a auto valve

I like your idea, but maybe consider tungsten as a rod instead of carbide. It’s 25% more dense and a lot easier to work