Lee Pro 4-20 melting speed question(s)

[Diadem]

I have approximately 100 lbs of range lead cast into soda can shaped blocks about 8lbs each. I have new Lee pro 4-20 fitted with a PID controller. I want to smelt these down to nice little bars for casting. I have metallic antimony in pieces approximately ¼ inch and smaller, and I have 50/50 solder. Unfortunately, I only have access to an area to do this in for several hours at a time.

How long would it take to melt a batch of one 8lbs block plus antimony and tin?
Would I be able to do 2 batches at a time (approximately 18lbs)?
Will I have problems with the antimony or does it alloy in pretty quickly?

Thanks for all help, wisdom, guidance

[Sasquatch-1]

If your antimony is in the form of some sort of printer's type, there shouldn't be a problem.

As for melting down those large ingots, have a propane torch handy to help heat up and melt. Otherwise, it could take considerable time to heat the ingot to melting temp. You would probably do better with a decent external heat source and a small cast iron pot and pour smaller ingots.

[Walter Laich]

when I used this pot I left it full of lead--took about 30-45 minutes for it to melt and get up to pouring temp

[JonB_in_Glencoe]

Pure antimony can be a problem, there is a special process to blend that into a Lead alloy.
Also, the heating element of the 4-20 is a coil around the middle of the pot liner, so your popcan shaped ingot won't be touching more than 5% of the liner sides, so heat would not transfer very efficiently, so it'll take a long than usual to melt your alloy, than if you had small ingots. I bet we are talking 2 hours per batch.

[trapper444]

I was using my Lee Pro 420 i lost everyting i owned back in 2021 December 12th just two days after the EF4 Killer Kentucky took over 90 people livesmy home for nearly my entire life i had 29 years of reloading and casting i loved all reloading and i now have so much fun when i cast my own round balls for my revolver 1858 Remington New Army Buffalo /Bison 12" bbl Brassed frame and i have the revolver for almost 4 years and i usr mostly 25 loads ive shot some 30 grain loads and they shot awesome but not because of me I just keep the setting near 7 but not hotter than that i haven't ever used it past 7 mine gets too hot but i have not used anything to see for sure of the actual Temperature i have always get good round balls for the revoler i well i used to have it was lost in the fire i just now getting a desktop running so i can start trying to buy the casting tools i lost and i had cast 1344 44cal round balls i had been working on stocking up on my 44 cal round balls lost the all my new twice used i just had bought and my Lee 6 cavity 454 cal. and the handles i had bought them new and I had a 2 cavity Lee mould i used until i got my 6 cavity man that was lighting i pourd it on no pun intened lol God will help me and i enjoy helping others too Folks i am sorry ill hush and lets all pray that I will be able to beging casting again i love it and i am going to buy the equiptment back i don't mind using a good used equiptment I will post my progress as i begin to replace my losses

[Doughty]

trapper444, I'll sell you some periods at a really good price.

[JonB_in_Glencoe]

[Sasquatch-1]

[gwpercle]

I have a Lee Magnum Melter 20 lb. capacity pot , for use with a dipper .
No PID or anything ... just plugged into wall @ 110V.
Fill the pot with mini-muffin ingots ( or fill with COWW ) set the Lee Dial on #8 or #9 to get things melted and at that setting it is molten in 30 minuts ... 45 on a cooler day . I cast untill I get the mould hot and slightly frosted boolits 10 casts and turn the pot down to #7.5 . Later I will lower temp to #7.25 on the Lee Dial .
I like to cast hot and use a dipper ... cold days are a no-go ...the cold just makes getting things hot a big chore !
Gary

[Winger Ed.]

It might be faster to cut the blocks if ya need to so they'll drop into the pot
and add the 'goodies' as you need to for a casting session.

Pre-melting/mixing all that and then melting it again to cast
reminds me of what I'd tell the young guys I used to work with:

"Don't make extra work for yourself. Plenty of other people are more than glad to do that for you".

[BattleRife]

How long would it take to melt a batch of one 8lbs block plus antimony and tin?
Would I be able to do 2 batches at a time (approximately 18lbs)?
Will I have problems with the antimony or does it alloy in pretty quickly?

I spent a little extra on my PID and got a model with a data logging feature, it can record all the settings and readings at regular intervals to a laptop as I work.

Here is a graph record of two heatup trials from ambient to casting temperature, running 4kg of lead in Lee Pro 4-20 pot, comparing the stock Lee dial temp controller with a tuned PID:


If 18 lbs fits in your pot you can do it, but it will be really full, I think the 20lbs number is optimistic for practical operation. I expect heating one big batch would be more efficient than 2 smaller batches, in terms of time and energy.

If you do not get above the melting point of the antimony it will have to get into the melt by dissolution, which I expect would take hours.

[Diadem]

Just to offer an update. I have now smelted these blocks into lyman bars with the right ratios of Antimony and Tin. I smelted at 780. The blocks melted in around 15 or 20 minutes. I crushed the raw Antimony into dust ¼ mesh and below. The bigger chunks of Antimony would float on top until I dropped in some wax to flux and then it would go right in. The pot will not hold two full batches (about 20 lbs) So I would smelt one batch and pour off some bars until it was half gone then drop in the next batch, melt, flux, and repeat. I could do 6 batches (about 50 lbs total) in three hours. In two sessions I now have about 100lbs of 92-3-5 ingots for making bullets.

Thanks all for guidance!!!