@#$%!@ Cerosafe!

[Black Jaque Janaviac]

What the ??

How do you guys make chamber castings with cerosafe?

I got some and it is a royal pain to work with. I did what I thought was according to instructions, but it still produced a butt-ugly wrinkly cast and now I've got a bunch of cerosafe stuck in my action.

I tried preheating my chamber by running hot water in it. Then a quick drying with a swab. Chambered a dummy round, put a patched jag down the muzzle, used a funnel and short tube to pour the cerosafe in. Then, with little warning, it overflowed, and got all over the inside of the action and promply froze.

I touched it a bit with a torch enough to pop out the chamber cast - did I say it looks like ****? But there's still a bunch of cerosafe in the action.

How do I clean it out?

How do I go about making a cast that looks right and doesn't make such a mess?

[MtGun44]

I warmed the action with a hair dryer, put a patch in as a plug, melted the cerrosafe and
poured it in from a paper cup, melted with a hair dryer. Easy, made a decent cast, not
perfect, with a few bubbles, but easy to measure.

Bill

[UtopiaTexasG19]

Contact the manufacturer and get instructions from them how to remove the stuff from your "action".

[35remington]

Remove the action from the stock. Since the metal is a good heat sink you need a more enthusiastic source of heat applied over a longish period of time. Suspend chamber over a medium intensity stove burner with a block of wood on each end to elevate. Allow to remain until chamber area is too warm to allow comfortable grasp for an extended period of time. This approximates Cerrosafe's melting point of around 180 degrees or so.

Good casts result. Ensure that the bore plug, if of cloth, does not have stray fibers that will be hard to remove from the casting.

If a scope is present take steps to protect it from heat, such as an insulating cloth or reflective material.

[geargnasher]

Honestly, I don't bother with the stuff ever since a member here described how to make an impact slug with an annealed case filled within 1/4" of the mouth with WW lead and topped with a soft lead slug. After chambering it and forging it to the chamber and throat dimensions with a taped steel rod and hammer, it is more accurate and durable than Cerrosafe anyway.

Gear

[Wayne Smith]

Gear, that works fine until you have an unknown chamber to evaluate! Then it's back to the cerrosafe.

[44man]

That is all I use it for, to find what caliber the gun is.
I never got the right measurements from the stuff.

[fixit]

i've not done this, but bob brownell (now deceased, operation is being run by his son) hadb a write up in 'gunsmith kinks', the original volume, how you could make an epoxy casting of a chamber. make sure you coat the chamber with a good release agent, and pour away.

[montana_charlie]

But there's still a bunch of cerosafe in the action.
How do I clean it out?

What kind of action?

How do I go about making a cast that looks right and doesn't make such a mess?

Drill out the primer pocket in a used cartridge case. Make the hole as big as you can without ruining the case. You want to be able to pour through it.

Trim off a little from the mouth of the case so you can get a good reading of the actual chamber end. Take off around a tenth of an inch.

Plug the bore at a point where the full rifling diameter is present.

Measure out enough Cerrosafe to make three or four bullets of the type used in the rifle you are dealing with. You want enough to make a model of the front of the chamber and the throat, and enough to be anchored inside the case. You will not need to fill the case with Cerrosafe.

Place the case in the chamber and begin heating the breech end of the barrel.
Propane torch, heat gun, maybe even a hair dryer are options for the heating.
Laying outside in the sun CAN produce temperatures that are too hot to hold in your hand, and that is what you are after.

When the barrel is hot, melt the Cerrosafe and pour it into the chambered case.
Since there is not enough alloy to fill the case, you don't need to be careful about an overflow. Dump it in quick ... while everything is hot ... and make note of the time. Keep some pressure on the case head so that the brass doesn't try to float upward on the (heavier) Cerrosafe.
The casting will be at the proper state for measuring at the one hour point after pouring the cast.

When the alloy hardens push the casting out with a rod. The heat in the barrel may cause some delay in reaching this point, but it will happen within thirty minutes of pouring. Don't wait longer than thirty minutes.
That is when the casting is at it's smallest dimension.

Any other questions ... ?

CM

[blackthorn]

CERROSAFE:


While the makers of Cerrosafe produce several different alloy combinations, the one we are likely to be working with consists of the following percentages: Bismuth - 42.50%, Lead – 37.70%, Tin – 11.30%, Cadmium – 8.50%. Note: Cadmium is very toxic () so use good hygiene and avoid breathing the fumes. We all know the harmful effects of inhaling or digesting lead. Cadmium is even worse. Its compounds are extremely () toxic even in low concentrations, and will bioaccumulate in organisms and ecosystems. So use similar but even greater caution when working with Cerrosafe as you would when handling lead.

Notes on Cerrosafe:
 Melts between 158 and 190 degrees Fahrenheit
 Should be melted in a clean iron ladle without direct flame on the product.
 The chamber being cast should be cleaned thoroughly and a thin coat of oil or graphite applied.
 Reusable

Contraction - expansion factor versus time, after casting, measured in inches per square inch:
 2 minutes -.0004"
 6 minutes -.0007"
 30 minutes -.0009"
 1 hour +-.0000"
 2 hours +.0016"
 5 hours +.0018"
 7 hours +.0019"
 10 hours +.0019"
 24 hours +.0022"
 96 hours +.0025"
 200 hours +.0025"
 500 hours +.0025"

Basic Instructions:
 Plug the bore about one inch ahead of the throat of the firearm using an appropriate size cleaning patch.
 Pour the molten alloy directly into the chamber until full and allow it to cool; it will turn a shiny silver color. As soon as it has cooled enough that it is no longer a liquid (and doesn't present a burn hazard), run a rod into the bore from the muzzle and tap the casting out of the chamber. Take care not to overfill the chamber as the alloy will then run into the locking lug area, making removal extremely difficult. Any recessed areas can be plugged with modeling clay prior to pouring.
 During the first 30 minutes of cooling Cerrosafe shrinks and then begins to expand. At the end of one hour it should be ‘exactly’ chamber size. The Cerrosafe will manage to find its way into some pretty tight places so it is easier to have the rifle stripped to the frame prior to commencing the job. Clean the chamber, lightly oil it (then wipe it out with a patch), plug the barrel at a point that allows the formation of about an inch of rifling to be included in the cast, and cast it.

Cerrosafe's melting point is below the boiling point of water so you can use a plastic funnel with a short length of vinyl tubing to get it into the chamber. The tubing should be just long enough to reach the chamber with the funnel set through the back of the receiver. Heat the Cerrosafe in a skillet ashtray, or other container with a pouring spout, over a heat source set on low. As soon as the cast has set up, push the ‘plug-patch’ along with the casting out of the receiver with a wooden dowel or brass rod.


When making a Cerrosafe cast of a high-wall rifle, the action must be disassembled and, depending on when the cast is measured, a mathematical adjustment (see above chart) may be necessary due to material expansion. Also, when using Cerrosafe to determine case OAL, headspace must be measured separately, which can be somewhat complicated.

An alternative to using Cerrosafe or the pounded slug method is to make a sulpher or a sulphur/graphite cast. To do this, make up a mixture containing a ratio of approximately two-thirds sulphur to one-third powdered graphite. Sulphur requires a much higher melting temperature than Cerrosafe but it has the advantage of neither growing nor shrinking once the cast has set. As noted, a chamber cast can be made using just sulphur but these casts tend to be somewhat hard to remove and they tend to be brittle. The addition of graphite in the casting makes it less brittle and easier to remove once it is hard.

A 4-lb. sack of sulphur can be had cheaply at the garden centre. Clean and degrease the chamber, put a paper plug about 1/2" into the rifling, drop a piece of cotton string into the chamber, do not use synthetics, have a wood dowel longer than the barrel and of smaller but as close as possible to the inside diameter on hand. Alternately, you can make a barrel plug out of cork or other stiff material, attach the required cotton string through the plug and push it into the chamber/barrel. Place some sulphur in a small pan with a pour spout, using, preferably an electric hot plate, slowly heat the sulphur until it melts, do not let it catch fire, the smoke is () poisonous. Stir in the powdered graphite and pour in enough of the liquid mix to just fill the chamber, wait until the cast is completely hard, this will depend on how large the chamber is, which governs the mass that has to cool down. Carefully push on the cast with the dowel while firmly pulling on the string; it should come out easily once it starts to move.


As noted, unlike Cerrosafe, sulphur cast dimensions of the chamber do not change at all over time, so how soon after casting you measure the cast is not important. Sulphur is one of the few elements that do not change dimensions when going from a liquid to a solid state. Casts made with sulphur do not change shape or dimensions even after many years. Molten sulphur can also be used to set machinery anchor bolts in concrete.

The inclusion of graphite allows the casting to release very easily after it cools. The best ratio, is somewhere between 10% and 30% graphite. Use a piece of poly tube through the receiver, pressed firmly against the rear of the chamber to keep from spilling it all over. Stick a funnel in it and pour until you see it in the tube. These castings can be remelted for re-use or they can be marked for identification and kept for future reference.

There you go. Have a great day.

[rbertalotto]

it is more accurate and durable than Cerrosafe anyway.

This might not be true.

That lead slug will grow quite rapidly once it is removed from the chamber. Lead under pressure like this has quite a bit of "spring back". Not much, but enough that it wouldn't pass muster in a good engineering lab.

Cerrosafe was designed specifically to be extremely accurate at the time given above. Other than an optical comparator or a million dollar laser measuring device, nothing is as accurate as Cerrosafe.

[geargnasher]

No doubt that's true, Roy, but accuracy is dependent on the user. Impact slugs are a very valid, easy, and safe way to check the same thing, and will be plenty accurate for boolit caster's purposes for years to come after they're forged.

Gear

[44man]

Having been a gunsmith and use much of the stuff, I would measure every 10 minutes and never got actual perfect measurements. In 1 hour, it was always larger so time has to be to the millisecond I guess.
Pure lead slugs always worked better.

[montana_charlie]

Contraction - expansion factor versus time, after casting, measured in inches per square inch:
 2 minutes -.0004"
 6 minutes -.0007"
 30 minutes -.0009"
 1 hour +-.0000"
 2 hours +.0016"
 5 hours +.0018"
 7 hours +.0019"
 10 hours +.0019"
 24 hours +.0022"
 96 hours +.0025"
 200 hours +.0025"
 500 hours +.0025"

Some (most?) complain that their measurements of a known dimension don't seem to be properly matched when using Cerrosafe to model the volume.
The explanation below may be of some help with that.
CM


I puzzled over the expansion factor of Cerrosafe for a long time. Nothing ever seemed to come out right when I applied their expansion values to the elapsed time after casting.

Then I went back and READ THE DIRECTIONS CAREFULLY. The wording is slightly misleading
(Contraction - expansion factor versus time, measured in inches per square inch)
but the gist of it is that one needs to subtract the value from the SQUARE of the measurement of the cerrosafe and the take the SQUARE ROOT of the result to obtain the origional dimension of the cerrosafe 1 hour after casting. It seems to work both for diameter and length.

For example, a casting of my 40-65 Ron Long chamber neck measured 0.4305" one hour after taking the cast.

24 hours later the neck measured 0.4330"

So, Squaring 0.4330 equals 0.187489 and subtracting Cerrosafe's recommended 0.0022" value leaves 0.185289 and then taking the square root gives a value of 0.43045 - quite close to the origional value of 0.4305"

Try squaring your values, subtract Cerrosafe's time-value [quoted above] and then take the square root of the result.

It works for me and gives me values that are close enought that I can live with.

[Ervin]

In a reprint of Hatcher's "Textbook of Pistols and Revolvers" there is a formula for making casts. Powdered sulpher = 2 ounces; Powdered lampblack = 3 grains; Gum camphor dissolved in alcohol = 3 drops. Haven't tried it.
Ervin

[blackthorn]

Thanks, I will have to try that next time I use Cerrosafe.