Noob confusion

[msw]

OK--I'm really confused after reading here & the lasc cast bullet articles regarding ternary alloys (SN/Sb/Pb) and that the components ARE mixed an can't be seperated. One article liked these alloys to salt & sugar dissolved in water, and that, once dissolved in lead--antimony & tin don't seperate.

When I melted a bunch of RotoMetals 30/70 allow, I skimmed a 20oz can of slushy, silvery material. This is out of about 10lbs of alloy. I tried mixing it back in, but it was like runny oatmeal. I remember thinking--wow, that's why RotoMetals is cheap--they sent ****! But now I don't think so...

Now I'm reading about antimony seperation & fluxing--I used boric acid to flux, then melt my bigger bars of 30/70 antimony/lead into 1lb bars--but have all this "silver crud" that I think, retrospectively, is antimony.

I haven't cast a bullet--just smelted wheel weights, alloy & lead sheet into 1lb bars--I WAS going to try casting this weekend, but now think I shouldn't until I get this resolved. Fortunately, one of the officers at my range is willing to help me, unfortunately, our schedules are so screwy, we haven't had a chance yet.

My reading tells me 2 conflicting things--the tin & antimony WON'T seperate, and that they WILL and need to be fluxed back into the melt. Before I make another expensive mistake (my last one was melting wheel weights without looking for zinc ones--now I think I've 10lbs of contaminated WW ingots), can someone shed some light on my question:

If I have non-dissolving, silvery metal in a pot of RotoMetal 30/70 alloy--should I be throwing it out, or is it antimony? If I recall, the pot was about 700 degrees--not sure, as this was a few weeks ago.

Thank you for the help.

msw

[GP100man]

msw

First WELCOME TO CASTBOOLITS.GUNLOADS.com!!!!!!

My take is I use parrafin to flux with & at 700f-800f if it comes to the top it gets skimmed until i see summtin shiney & clean!!

While smeltin WW I watch closely to temp to catch the zinc ones when they surface!!

I`ve remelted WW s & it did`nt change the bhn of it , even after skimmin some fairly nasty shtuff offin it.

I`m with the school that to remove alloys it`ll take a furnace that the caster does`nt have access to !!!!

[cbrick]

msw, odds are it is antimony and no, you don't want to skim it off. If your going to do that why buy it in the first place?

The few times I've run across this problem it reduced back into the melt very easily using sawdust as flux. I've never used a wax as flux so can't speak to that.

No, they won't seperate "but" the metals melts at different temps, antimony last. The antimony on the surface of the melt looks like silvery oatmeal. Rather than trying to melt your 30/70 alloy first try first melting the alloy that you'll be adding the 30/70 to, then add only the percentage of 30/70 to the melt needed to reach the percentages your looking for.

Rick

[GP100man]

I think cbrick is rite at the temp to melt every thing except what ya wanna keep .

I had some alloy that made a foam of lite fluffy lite gray mess on top one time.

more heat & fluxing????

[msw]

I had a feeling it was a temperature thing. I only had the 30/70 in it. I have about 100lbs of pure lead sheeting, which is why I got the 30/70.

I thank you for your help.

I'm gonna wait on any more fiddling withthis project until I get experienced "adult" supervision. :oops:

I'm sure once I get the basics down, this will be OK, but dang--this is tougher than reloading!

Thanks again.

[montana_charlie]

While you're waiting for your mentor's schedule to coincide with your need, you might send off an email to Rotometals.
Tell them that you just want to melt that 30/70 down and pour smaller ingots. Describe your observation, and ask for their recommendation to get around the oatmeal syndrome.

If they tell you anything (that works) post it here...

CM

[geargnasher]

The Sb is separating due to a vast difference in melting point from the Pb.

In order to get that clumpy oatmeal antimony back in the melt, add tin and flux with lots of sawdust, and use plenty of heat. I don't know why the sawdust helps get the antimony to mix back in the lead but it does. You didn't say what alloy you were shooting for, but antimony will bind with tin much more easily than lead, so take the 20 oz can of the stuff you skimmed off, add half that amount of pure tin, cook that up until it blends, and mix that at 6% total by weight with pure lead to get a good ready-to-cast WW equivalent, or whatever composition you're looking for.

Sn/Sb makes it's own "intermetallic" compound within the Pb/Sn/Sb alloy, and as I understand it the key is to never have more tin than antimony in any alloy unless it is a true Pb/Sn binary.

I want to get some of that Rotometals 30% for the same reason, cheap prealloyed Sb, and I think the thing I would try to do is melt 30% of it's weight in Sn and add the 30% Sb alloy to IT. Then do the math and add accordingly to pure lead. It would make cheap Lyman #2 with sewer-pipe lead or whatever you have that's pure.

Several people here have good techniques for getting Sb to alloy with lead, you might to a search.

Gear

[cbrick]

I had a feeling it was a temperature thing. I only had the 30/70 in it. I have about 100lbs of pure lead sheeting, which is why I got the 30/70.

I thank you for your help.

I'm gonna wait on any more fiddling withthis project until I get experienced "adult" supervision. :oops:

I'm sure once I get the basics down, this will be OK, but dang--this is tougher than reloading!

Thanks again.

Na, not really tough but like any new thing it can seem overwhelming at first. A few basics once learned and you'll be an old pro telling a new caster all about the same problems you had when you first started. In much of casting there are no hard set rules and there are nearly as many different ways of doing things as there are people doing it, that's where some of the confusion comes from with new casters. There are also a lot of old wives tales hanging on from days gone by but the bottom line is that if it's working for you and your getting the results you want your doing it right for you. The type of flux is an example, I use sawdust, someone else may use candle wax and think that's the "best" way. If they are happy with wax they are doing it right for them. I am more than happy with sawdust and therefore am doing it right for me.

No need to wait for Grandpa to come over to help. Just melt say 10 pounds (I don't know what type of pot you use) of your soft alloy to 700 degrees. Next get your calculator out and figure out how much of your 30/70 you need to add to reach your desired percentage of antimony. Add it and flux and stir and stir and stir. I suggest no more than about 4% antimony unless your going to shoot just paper.

Rick

[lwknight]

The slushy stuff IS the antimony. When I melt the Rotometals Superhard, I just stir it and quickly dip it into smaller ingots. Never Skimming anything. If you get a bit of oxide so what? You can deal with it when you mix your alloy.

The 30 percent does look like runny oatmeal. You can actually make a hole in it with a spoon and it will fill with pure lead leaving the antimony piled up around it.

Remember, from now on just stir the heck out and pertly dip it out to your molds.
Mix the high antimony lastly after you have the rest of the recipe melted.

If you mix a larger batch, you can just break the bars with a hammer, weigh, and pre melt the balance of the recipe to fit whatever size chunk you breal off.

[lwknight]

You do not need to add tin to remold the 30% SB!! although I cannot say that it will not help a messup like dipping it out. Thats new territory for me.

[msw]

I wasn't trying for any ternary mix--I thought 1 pound ingots would be easier & more accurate than cracking up the larger ingots.

Thanks again for the help.

[lwknight]

I wasn't trying for any ternary mix--I thought 1 pound ingots would be easier & more accurate than cracking up the larger ingots.

Thanks again for the help.

Thats exactly how I did it. Small ingots make recipe mixing easy.