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Cerrosafe™ - low melting point alloy

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Cerrosafe™ - low melting point alloy

Unread postAuthor: bluerussetboy » Thu Jan 17, 2008 11:59 am

While cleaning up silverdooty's workshop the other day I came across a couple of lbs. of Cerrosafe™.

What Is Cerrosafe™

Brownell's wrote:Cerrosafe™ casting alloy is used any time a “positive” copy must be made
of a rifle, shotgun or handgun chamber, neck, throat or bore. Chamber casts
are used to determine the caliber of an unknown or unmarked firearm, and
to verify the marked caliber if it is suspected that the original chamber has
been altered. It is also used to check dimensions and condition of the neck,
throat, and bore to help determine bullet fit and case neck turning requirements.
Cerrosafe shrinks slightly during initial cooling. It then expands to the
chamber’s original size about one hour after cooling to room temperature.
After cooling for about 200 hours, the chamber cast will expand about .0025"
over the actual chamber size. Cerrosafe is completely reusable; the chamber
cast can be remelted and reused after all necessary measurements have
been taken.

Brownell's wrote:HOW TO USE
Cerrosafe has a melting range from 158° to 190° F.
Note: Overheating may cause separation of the components of Cerrosafe alloy.
Melt Cerrosafe in a double boiler or other means of clean, indirect heat.
It should be poured from a clean ladle. If a heavy iron bullet caster’s or
plumber’s ladle is used, a propane torch with a low flame can be used to heat
the ladle from the bottom until the Cerrosafe is completely molten. A bent
tin can may be used as a ladle, with the lip bent to form a pouring spout, and
locking pliers (such as Visegrip brand) used as a handle for the can. If a small
can is used, it should be set on a piece of heavy sheet steel and the heat applied
to the steel from underneath with a propane torch. An industrial hot
air gun can also be used to heat the Cerrosafe in a pouring ladle.

Cerrosafe™ is on sale occasionally for as little as $10/lb. Current prices range from $19-$24 per 1/2 lb. Expensive if you don't re-use it.

If you were to make foster style slugs for a 3/4 in.(~475 grains) spudgun you can get 14-15 reusable rounds out of a pound. Smaller caliber spudguns you would get quite a bit more reusable rounds.

Due to the Cerrosafe™ low melting point you would not need to use iron molds. Basicly if it doesn't melt in boiling water you can use it as a mold.

Things to consider:
Low melting point: 158° to 190° F
(water boils @ 210° F)
Available from quite a few online sources.

1 lb = 7000 grains
(bullet weight is usually measured in grains)

Cerrosafe™ can be some very pimping ammo for the spudder without the facilities to cast lead bullets.
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Unread postAuthor: potatoflinger » Thu Jan 17, 2008 12:04 pm

Wow, nice find! I just might have to get me some of that...
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Unread postAuthor: jackssmirkingrevenge » Thu Jan 17, 2008 12:06 pm

Interesting, you could practically use a drilled out block of wood as a mould :D

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Unread postAuthor: bluerussetboy » Thu Jan 17, 2008 12:20 pm

it is a proprietary alloy and i haven't been able to find any density specifications. over the years i have read that there is a large concentration of bismuth in cerrosafe. i will say i can't tell any difference in a lb of lead in one hand and a lb of cerrosafe in the other :wink:

wood, plexiglass, lexan, copper pipe just to name a few things molds could be made out of.
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Unread postAuthor: jimmy101 » Thu Jan 17, 2008 3:29 pm

Sounds similar to Wood's Metal;
Code: Select all
Wood's Metal is a fusible alloy that becomes liquid at approximately 158 °F. The alloy is comprised of bismuth, lead, tin, and cadmium.

MSDS sheet for Wood's Metal

You can get Wood's metal from United Nuclear for $18/225g.

Or, from Science Stuff.
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Unread postAuthor: Ragnarok » Thu Jan 17, 2008 4:15 pm

The low melting point alloy I usually think of is Field's Metal - it is on wikipedia, the forum just doesn't like the apostrophe in the url.
Which is an eutectic mix of bismuth, tin and indium, and it melts at about 144 <sup>o</sup>F.

It's not toxic like most other low temperature alloys (but it is soft like most others), but it does have a propensity to adhere to many surfaces, notably plastics.
It is a lot more expensive - it would cost me close to £600 for a kilo, because indium (over half the mix) is into hundreds of dollars per pound. The problem with indium is that it's used in LCD screens, so the price has risen sharply with the demand for flat screen TVs and monitors.
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Unread postAuthor: bluerussetboy » Sat Jan 19, 2008 8:18 am

After a little more research, I have found this.


Wood's metal will expand over time where as cerrosafe's expansion is minimal. wood's probably wouldn't make very good ammo due to this. :(
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