Metallurgists? Cerrosafe question?

[fatelk]

I have a bunch of cerrobend, and am thinking of making some into cerrosafe for chamber casting. I thought I'd see if anyone had done that before.

I found these percentages online:

...................bismuth.....lead.......tin..... ....cadmium
cerrobend.......50..........26.7......13.3........ .10
cerrosafe.......42.5.........37.7......11.3....... .8.5

If I calculated right, it appears that the relative percentages of everything but lead are exactly the same, so if I add precisely 1,236 grains of pure lead to a pound of cerrobend, I should have cerrosafe (assuming these percentages are weight). I have some soft x-ray wall lead that I think is about as pure as it gets.

I wanted to make sure that what I have is all cerrobend; some are ingots marked "Soule Medical 158" and some look like they have been remelted into a pan of some kind. I melted a small sample of each, suspended each sample by wire into a pan of water, and heated it on the stove with a digital thermometer in the water. All five samples melted within 30 seconds of each other at 164 degrees F. Allowing for a margin of accuracy in the thermometer, as well as a difference in heat transfer between the the thermometer and the samples, it seems reasonable to me that this is all cerrobend 158.

Anyone see any issues with my methodology? I don't want to ruin valuable alloy because of a math error.

[geargnasher]

If it was me, and I was planning to measure a chamber/throat/leade, I'd just cast some slugs with that x-ray lead and make an impact slug.

Gear

[Mooseman]

I looked at percentages and My math says 1540 grains of lead added to 1 pound cerrobend should equal cerrosafe percentages.
I arrived at that figure by adding the 11% higher quantity of Bismuth , tin and Cadmium in Cerrobend to the 11% more lead needed for cerrosafe hence 1 pound =7000 grains X .22(%) =1540 grains Lead needed to match Cerrosafe formula.
Someone Check My math.
Rich

[bumpo628]

I found these percentages online:

...................bismuth.....lead.......tin..... ....cadmium
cerrobend.......50..........26.7......13.3........ .10
cerrosafe.......42.5.........37.7......11.3....... .8.5

If I add precisely 1,236 grains of pure lead to a pound of cerrobend, I should have cerrosafe

I punched the 1236 grains of pure and one pound of cerrobend into my alloy calculator and the percentages match exactly.


I checked the 1540 grains listed by Mooseman and I get:
41% Bi, 39.9% Pb, 10.9% Sn, 8.2% Cd

[Defcon-One]

I checked Bumpo, just to be sure!

His numbers are dead on. So, your numbers are 100% correct. Alloy away!

[Mooseman]

so where did I go wrong ? 304 grains difference...

[fatelk]

Thanks guys. My high school chemistry is rusty; wanted to make sure I wasn't missing anything. I'll try half a pound to see how it works, then maybe carefully alloy the rest and try to sell some or something. I have way more than I need.

Mooseman, were you allowing for the fact that the finished product would be 1lb+ instead of just one pound? That's where I went wrong at first when I started calculating. I caught my mistake when I double-checked what the percentages would be of the final alloy.

[Pepe Ray]

? for Fatelk,
What is cerrobend?
What's it used for?
How would one come upon it?
Obviously I've never heard of it.
Thanks
Pepe Ray

[fatelk]

Cerrobend is an alloy very similar to cerrosafe, except it doesn't shrink as it cools. Not good for chamber casts.

It seems it has a number of uses. The one I'm most familiar with is bending thin walled tubing such as in a lab. If you just bend the tube, it will kink. If you melt some cerrobend in hot water (melts at 158 degrees F) and fill the tube, you can bend it without kinking. Then you dip it in hot water and melt it out.

Another use is to make fixtures to machine odd-shaped parts that you wouldn't otherwise be able to clamp in a vice. You melt some cerrobend in a square pan, position your part in the molten metal, and allow it to harden. You then clamp the whole works in your vice to machine. When done, dip it in hot water to melt off the cerrobend.

I've run across it a couple times looking for boolit metal. It's reusable but sometimes gets scrapped. It's a little disconcerting when you go to melt down what you think is a big block of lead, and it just starts dribbling all over the place before the pot even starts to get close to temperature for lead.

It also contains cadmium, which is more toxic than lead. Not real scary, but something to consider when handling or storing it. Cerrobend is worth about ten times as much as lead.

[Pepe Ray]

Fatelk;
Do you intend to sell any of your stash?
If so---How much would a pound cost me OTD/delivered?
In any case, thanks very much for the info.
Pepe Ray

[uscra112]

I've been in contact with the process of using a "low" melting point metal to "pot" parts for machining. It's how they grind the "Christmas tree" root form on jet-engine turbine blades. But Cerrobend melts at much too low a temperature to do that safely. Machining metal makes it get hot! Obviously I've got a sample of what Pratt & Whitney uses, (actually more than one), and I've tried to melt it once or twice. Whatever it is, it melts at a temperature above that of lead. Kirksite, maybe?

[acl864]

I have a bunch of cerrobend, and am thinking of making some into cerrosafe for chamber casting. I thought I'd see if anyone had done that before.

I found these percentages online:

...................bismuth.....lead.......tin..... ....cadmium
cerrobend.......50..........26.7......13.3........ .10
cerrosafe.......42.5.........37.7......11.3....... .8.5

If I calculated right, it appears that the relative percentages of everything but lead are exactly the same, so if I add precisely 1,236 grains of pure lead to a pound of cerrobend, I should have cerrosafe (assuming these percentages are weight). I have some soft x-ray wall lead that I think is about as pure as it gets.

I wanted to make sure that what I have is all cerrobend; some are ingots marked "Soule Medical 158" and some look like they have been remelted into a pan of some kind. I melted a small sample of each, suspended each sample by wire into a pan of water, and heated it on the stove with a digital thermometer in the water. All five samples melted within 30 seconds of each other at 164 degrees F. Allowing for a margin of accuracy in the thermometer, as well as a difference in heat transfer between the the thermometer and the samples, it seems reasonable to me that this is all cerrobend 158.

Anyone see any issues with my methodology? I don't want to ruin valuable alloy because of a math error.

I've made the conversion from cerrobend to cerrosafe before. I don't remember my exact calculation but IIRC I started with 3 1/2 lbs. of cerrobend and added a little over 1/2 lbs. of pure lead. Getting the lead to melt and mix with the cerrobend was a little nerve racking. I'd seen the dire warnings about the danger of cadmium fumes and I worked as quickly and safely as I could. I suffered no ill effects but looking back in hindsight, I was taking a significant risk to create something I could buy for less than $100. I've still got 4lbs. of my home made cerrosafe around here somewhere. Just enough for about 4 lifetimes. Not sure I'd do it again, but it can be done.

The Soule Medical 158 ingot and the alloy melted in the shape of a pot sound like they originated in an Oncology Department. Soule Medical is a supplier to that field and before it was largely replaced by Cadmium free low melt alloys, the 158 low melt was very commonly stored in liquid form in small pots over low heat to be used by the oncologists to make the molds used in Radiation Therapy treatment.

[fatelk]

Getting the lead to melt and mix with the cerrobend was a little nerve racking. I'd seen the dire warnings about the danger of cadmium fumes and I worked as quickly and safely as I could.

I hadn't thought about that. Did you melt the lead, then add the cerrobend to it, or the other way around? I'm a little concerned because cerrobend melts at 158 degrees F, and lead melts a lot hotter than that. Does anyone know if there is any risk of cadmium fumes from cerrobend at the higher temperature? I don't like to take chances with health and would be tempted to just sell it all and buy a pound of cerrosafe instead.

[acl864]

I melted the lead and then added the cerrobend into the melt as it cooled but before it re-solidified. The cerrobend and lead blended quickly and I didn't see any need for flux. I didn't use my thermometer so I don't know the temps involved. I was working beside an open garage door with a fan pulling any potential fumes off. I don't think I was exposed to any cadmium fumes but there is always some potential risk involved with projects like this one.

BTW- I like your methodology of using water to melt the low melt alloy so you can confirm the melting temperature. I've got about 20 lbs. of low melt alloy that isn't in it's ingot form. I've been told it's Cad Free alloy that melts at 203 degrees. I'm going to use your method to determine for sure if that's what it is.

[Mooseman]

Cadmium will not vaporize and become dangerous until it is past the boiling point of 1413 degrees f.
Melting point is 609.3 f.
Like other heavy metals, wash your hands after handling it before eating or smoking , and Keep cadmium plated screws out of your mouth !

[fatelk]

Thanks, acl864. That helps a lot to hear from someone who's done it.

Thank you Mooseman. That makes me feel better about messing with it. I've been looking up and reading the MSDS and other info on cerrobend. One safety procedure I found on it from a hospital or something mentioned only melting it under a vented hood, but that sure seemed a bit overboard to me, considering the low temperature.

I've worked with a lot of really nasty chemicals at work, and I don't like messing with something unless I know exactly what I'm dealing with.

[fatelk]

Well, I carefully alloyed a pound of it, and it works great. I made a few chamber casts and they come right out just like they should. I can't find my micrometer right now to check the expansion rate.

I'm thinking about making more to sell some, but don't know what a fair price is. I can find cerrobend and Wood's metal all over ebay, but no cerrosafe. Everywhere else cerrosafe is quite expensive, like $20 for half a pound. I could sell for a whole lot less than that.

Any market for this stuff?

[acl864]

Rotometals sells it as Low Melting Point Bismuth Based Ingot 158-190 Alloy for $15.99 per pound. A recent classified sale offered 2 lbs. ingots for $16 each/2 for $26 shipped. It went really quickly.

BTW-I used your method to test the low melt alloy that I have and found out that I've got 20 lbs. of cerrobend instead of the cad free alloy that I thought I had. I may try to sell it "as is" at some point in time.

[Splatter]

I'd happily pay $10/lb plus shipping for a few pounds of CeroSafe, after christmas (50 days and counting!)

[nanuk]

another thing Cerrobend is good for is if you don't have a lathe, just use the larger aluminum bushing for your barrel vise, and fill it with Cbend. Locks it in tight. heat gun melts it out.

CerroBend actually EXPANDS as it cools. that is how it can really lock things into place.

there are a bunch of Cerro products for different applications.