Printable View
Greetings,
My heat treat furnace is large enough to accept a 10# RCBS Lead Pot.
Years ago, I was gifted a solid chunk of Antimony.
My plan is to place the Antimony and Lead in the Lead Pot and put it in the oven at 1200 F. (Antimony melts at 1166 F)
Hoping the Antimony and Lead will go into solution.
Has anyone done anything this Harebrained before?
Not sure how 1200 degree Lead reacts with the atmosphere. (Nasty fumes, etc.)
Cheers,
Dave
You will be vaporizing the lead at that temperature. Very dangerous.
The boiling point of lead is ~1750° Celsius, though I think it’s the case that there will be some lead fumes to deal with even at lower temperatures (not much at typical lead casting and processing temperatures below 800°F, more at what you’re proposing).
Just like table salt, with a melting point of ~1475° Fahrenheit, that will dissolve into room temperature water, antimony will dissolve into lead well below Sb‘s melting point. I’ve never done it myself, but there are others here who say they have. Do a search to find their posts. The basic things they described is to break up the antimony into small pieces and to keep them submerged in the lead until they dissolve. I don’t know about any specific safety precautions that need to be taken. I’d guess it also is worth knowing how saturated a solution of Sb in Pb you can get. RotoMetals sells a mix of 30% Sb and 70% Pb, but I don’t know their exact method.
So much easier to harden your own metal with roto metal super hard. Roto metal super hard can be mixed into once you can reach 850°F.
Even lower, I think.Quote:
Originally Posted by Recycled bullet
https://castboolits.gunloads.com/sho...+lead+antimony
Three factors, melt lead, add tin to speed up the antimony going into solution, add antimony and hold under the surface of the melt and cover with sawdust to seal off oxygen. There are safety considerations when dealing with the antimony dust that you really do need to follow. It is in the "stickys".
I obtained real Antimony ore. Pure and smashed it in a heavy can to make a powder I could somewhat measure out. I made my own hardened alloy (L#2) by stir, stir, stirring in a tablespoon at a time into pure lead in my 20 lb pot. I would pour a sample, run downstairs and test with my Lee hardness tester and know if I needed to add more or dilute it. Only did that a couple times as I've been scrounging COWW and haven't needed to do that again. I kept the rest for the time when COWW will no long be found.
There is no need for that heat. I just melt the tin first into the alloy and hold the antimonny under the lead surface at 700F. It takes some time but the antimonny get alloyed into the mix.
Sent fra min YAL-L21 via Tapatalk
There is/was a special flux for melting and adding antimony to your melt. Roto Metals may offer it; google it if they don't.
I've never done it, but read a bunch and watched a video. As mentioned add the tin first and then put your antimony into some type of basket or screen so you can kept submerged. The way I understand it, the antimony is mostly dissolving into your alloy rather than melting into it. So it needs to be kept submerged.
Here is about the worst youtube video ever recorded, but this guy shows dissolving a chunk in a 10 pound Lee pot and his temp gauge seems to be at about 750.
https://www.youtube.com/watch?v=PqQ6LiJGKwQ
I guess if you have a ton of time and an XRF machine to check to see what you actually ended up with it is a good idea. Otherwise it is much easier and cheaper to use Rotometals alloys to harden your lead with known percentages.
So if antimony is already blended with lead/tin, will it stay in solution when it's melted?
I have a LOT of hardened #7 1/2 shot, high antimony stuff. When I melt it down I get a large amount of dross, almost like dirt, that has to be spooned off the top.
Is a lot of that the antimony ?
That's a really good question man. I've never melted birdshot but I wonder if that's graphite or carbon???Quote:
Originally Posted by Sudsy
When I melt the roto metals super hard by taking the ingots and placing them into a pot of molten lead if the temperature is not high enough to eat it immediately it makes oatmeal lookin stuff that I stir it and it warms up and then it becomes visually homogeneous.
That slush is just the high percentage of antimony and the melt needs to be hot to recombine with the lead. You probably have noticed that if you already have lead and tin in the pot, you will not have that. Due to the antimony and tin combining and then the lead combining with that alloy.
Melting shot requires having it hot enough to actually melt the alloy, and then defeating the coating of oxide and graphite. If you just spoon off the dross without fluxing and reducing, you are tossing good metal, and probably visible as fine spheres of shot in the dross.
Graphite, yup, I forgot about the graphite.
That explains the "dirt" on top
Does anyone have more info about the special flux? Does this speed up the prosess of melting chunks of antimony into the alloy? It works the way I do it but it takes a lot of time. The sb migrates grate into the alloy with sn added into the alloy first.
Sent fra min YAL-L21 via Tapatalk
Antimony is diff to alloy. I would just buy Monotype & go with that for blending alloy.
[QUOTE=hunter74;5639683]Does anyone have more info about the special flux? Does this speed up the prosess of melting chunks of antimony into the alloy? It works the way I do it but it takes a lot of time. The sb migrates grate into the alloy with sn added into the alloy first.
The product that the Antimony Man was selling is KLEANROL. This is the white crystal product that comes in a 50 pound bucket. At the time, it was available from Zaclon, Inc, 2981 Independence Road, Cleveland, OH I believe the phone number is 216/271-1871. The issue was that too many people were not following the instructions and having problems with the product. Also it is corrosive and proper handling and PPE is needed. For that reason Bill quit selling it. Bill is no longer with us.
Kleanrol® : A registered trademark of DuPont for a soldering flux crystal based on ammonium chloride and zinc chloride. Sounds like some nasty stuff, also something that is going to rust anything in your shop within reach of the vapors
Dave,Quote:
Originally Posted by fc60
Assuming your solid chunk of Antimony is pure, do you know why it was a gift? Because it is a pain in the Keister to blend into a lead alloy. Personally, I'd just gift it to someone else. But if you feel like experimenting, here is a good thread to give you some pointers, be sure to read runfiverun's posts more than once. You don't need high heat, 600º will do it, but you need the correct flux to create a oxygen free environment...and having the Antimony in small chunks (pea size) helps a lot.
https://castboolits.gunloads.com/sho...-melt-antimony