Need Info For CERROBEND

[GRUMPA]

I have some Cerrobend alloy left over from my machining days and I need to make a chamber cast. Problem is if memory serves is that it expands when it cools. But after doing searches there was one mention of someone adding lead to Cerrobend to turn it into Cerrosafe.

Anyone out there know what the blend is to do this? How much lead lead mixed with Cerrobend to make Cerrosafe?

[Defcon-One]

Found this on wikipedia:

Wood's metal, also known as Lipowitz's alloy or by the commercial names cerrobend, bendalloy, pewtalloy or MCP 158, is a eutectic, fusible alloy with a melting point of approximately 70 °C (158 °F). It is a eutectic alloy of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by weight.[1] It is named after American metallurgist B. Wood.

http://castboolits.gunloads.com/imagehosting/178454eb225316ed3a.jpg


You'd need to add Lead, then remove some Tin and Cadmium and a bit of Bismuth. Not likely at home!

Update: While doing the math I noticed the Cerrosafe formula totals 106.5%, go figure! Maybe and intensional error to protect their formula, maybe a typo?

Also:

Wood's metal (cerrobend) is toxic because it contains lead and cadmium, and therefore contact with the bare skin is thought to be harmful, especially in the molten state. Vapour from cadmium-containing alloys is also known to pose a danger to humans. Cadmium poisoning carries the risk of cancer, anosmia (loss of sense of smell), and damage to the liver, kidneys, nerves, bones, and respiratory system. Field's metal is a non-toxic alternative.

Maybe just buy the Cerrosafe?

[jpatm2]

Double check my math on this one, but using values listed in the chart above if you add 9 parts Cerrobend to one part of pure lead, you get an alloy with the following makeup:
Bismuth 45%
Lead 34%
Tin 12%
Cadmium 9%
It's not too far off from Cerrosafe, maybe make a small amount, cast a test boolit and take measurements to see if it contracts then expands like Cerrosafe should.

[GRUMPA]

Thanks guys this will give me a real good reference point. Finally got home last night from the big town (90mi round trip) and got a ladle the other half wont freak out if I use. Hers are strictly off limits with anything I do so I had to make do with a cheap $2 alternative. I think I should have some good results with it though.

[bumpo628]

If you mix exactly 5.1 lbs of Cerrobend with 0.9 lbs of pure lead, you'll get:
42.5% Bismuth
37.7% Lead
11.3% Tin
8.5% Cadmium

According to my assumption below, this will give you the formula for Cerrosafe.


If you look at the formulas for the two alloys, it would seem that the lead and tin number match up to an even number and the bismuth and cadmium do the same. So, I take that to mean that the lead and tin numbers in the cerrosafe formula must be right and the bismuth % is in error (since the cadmium is too specific and the bismuth is a round number). If you adjust the bismuth down to 42.5%, then it adds up to 100%.
Cerrobend: 50% bismuth, 26.7% lead, 13.3% tin, 10% cadmium
Cerrosafe: 42.5% bismuth, 37.7% lead, 11.3% tin, 8.5% cadmium

[Defcon-One]

If you mix exactly 5.1 lbs of Cerrobend with 0.9 lbs of pure lead, you'll get:

42.5% Bismuth
37.7% Lead
11.3% Tin
8.5% Cadmium

According to my assumption....


Bumpo: Good logic and a good bet. I just found this online today. Looks like you are a genius!


Cerrosafe is one of a family of “Cerro” casting alloys and is comprised
of bismuth (42.5%), lead (37.7%), tin (11.3%) and cadmium (8.5%).

Here's the link to where it was: http://www.texas-mac.com/Discussion_on_Case_Lengths_Chamber_Casts_and_Impac t_Impression.html

[Chicken Thief]

Look what our sitesponsors say:

http://www.rotometals.com/Low-Melting-Alloys-s/21.htm