cerrosafe

[dh2]

I clearly did not do some thing right. I bought 2 barrels at an estate sale with a 98 Mauser action , the first one I started with was marked 308 Win. trying to head space it realized it was 30-06 cut long. So the second barrel I wanted to make sure it was what it was marked to be 8 x 57 (8MM Mauser to me) I was the only one to bid on it so I got it for $7.00 I have the reamer and die's for 8mm-06 and an action to build it on. So I attempted to chamber cast it. with a lee 4 lb. pot and cerrosafe from roto metal.
my first attempt I put 3 cleaning patches below the thought and pored the alloy in let it cool tell appearance changed and taped it out with a 1/4 inch rod, it looked like it was cast in a cold mold and came in too as it came out.
second attempt was the problem , I tried to do it the same way , when trying to get it out was a real problem, I melted it out with a small propane torch since the melting point is only 160 deg.
what did I do wrong here, was the barrel being warm from the first attempt a problem, or the alloy to hot. or some thing else ??

[Bent Ramrod]

Breezy descriptions of chamber casting by pros writing in books or magazines do not, as you’ve noticed, always describe the reality for the rest of us.

What I do is wipe barrel and chamber with a cloth patch dampened with sewing machine oil, just enough for a slight coating on all surfaces. I then run the cleaning rod and patch in from the muzzle until the patch is ahead of the throat, and clamp the assembly vertically in a padded vise so the handle of the cleaning rod rests on the floor and the chamber is up clear of the vise jaws.

I boil water and melt the Cerrosafe in a dipper in the boiling water. While the water heats up, I run a hair dryer over the chamber end of the barrel until it’s good and warm—too warm to hold comfortably, if possible.

I put on gloves, pour the molten Cerrosafe into the chamber, being careful to keep it from getting into cross cuts or areas that might result in mechanical locking of the casting in the chamber. Some modeling clay, properly applied, might be necessary to block these areas off. If the barrel is on a (stripped) receiver, I might use a small funnel.

As soon as I see the top of tha casting frost over, I open the vise, grab the barrel with one hand, and tap it downwards on the cleaning rod. A couple “klonks” gets the casting out, which I catch in my other hand.

I find the waiting time recommended by the instructions is a sure-fire way to stick the casting in the chamber. Others, apparently, have no trouble this way. Sometimes I see a scuff where some unsolidified metal broke away, or a divot where the oil bubbled up, but this generally doesn’t prevent good measurements. I do wait the recommended time to measure the casting, after it’s out.

[Moleman-]

Bent ramrods method is very close to mine only I just melt the cerrosafe in the dipper heating the bottom of it with a torch. It doesn't take much heat. Another thing that makes it easier to break free is using an old barbless cleaning jag with a single patch on it like you'd clean the barrel with. More patches or a rolled up patch ahead of the jag will just cushion the impact and make it harder to knock out the casting. The jag barb often will get broken off or bent in the process if you do enough of them, so older jags you don't care about or jags with short barbs are better. Also don't use your nice ball bearing handled cleaning rod. Often I'll use solid steel or brass rods closer to bore size and not much longer than the barrel than a couple inches so you don't get much flex.

[2152hq]

Lightly oiled patch on a Cleaning rod . Insert from the muzzle and stop just short of the chamber.
That'll plug the chamber and will often give you a casting of the throat and the rifling as well.
Don't attempt to get a casting of too much of the rifling or the casting will be very difficult to remove.

Melt the Cerrosafe in a small tin can or other container with a lip on it for pouring by simply setting it into a larger pan of boiling water.

Yes you can melt it quickly by using a torch or other open flame, but the problem is that you usually get the stuff too hot and that starts to sparate the alloys that make up the mixture.

While the Cerrosafe is melting in the tin can in the boiling water,,,heat up the bbl you are taking a cast of gently.
You can use a torch here, but again be gentle. No need to make the bbl any hotter than the 200*F that the Cerrosafe will be comeing off of the double boiler.
This just to help the molten Cerrosafe from giving you a wrinkled casting. Though you may still get some as the stuff cools off so fast in use.

When you have the bbl warm/ and the cerrosafe melted,,carefully pour the chamber casting.
Pour slowly but continuously. It'll fill quickly and overflow most likely. That's OK.
I pour it so it slightly over flows. You can't get a squared off end/base to the casting anyway, so a little extra over the end won't matter.

Let it cool for about 10min. Then punch the casting out by the end of the cleaning rod at the muzzle.
The casting will usually be attached to the patch you used to seal the bore. I clip the end free.


Cerrosafe contracts upon initial cooling. That is the known feature of the metal.
That makes it easy to remove the casting.

The metal does however then expand upon further cooling back up to near full 100% size of the cavity it was cast in.
That full expansion to 100% takes place around 30min +/- after initial casting.
Outside temp makes a lot of difference in the time of course.
But the casting will expand back to just under the cavity size. There is a known final % of shrinkage of the metal (and it's only in the fraction of a %) so smart guy engineer types can use math to figure actual size of internal cavities cast with the metal.

IF you wait and let the casting cool and the casting expands back to or near that 100% size,,you will not be able to punch, kick, push the chamber casting back out of the chamber. Not in one piece at least. It'll be a press fit in there and melting it out is about your only choice.

[Texas by God]

A member here suggested parrafin chamber casts and explained how to do it. Very easy! I did it on my SMLE and Krag( easily accessible chambers on both) and it worked swimmingly. Probably not as precise as cerrosafe- but good enough to tell WTH the chamber is.
Just saying....

Sent from my SM-A716U using Tapatalk

[yeahbub]

Something that isn't generally made plain in the advertisements for cerro-safe is that there are different alloy formulations. Some expand on cooling, some shrink, and some are expansion-neutral. Check with the manufacturer to see which one you have. I once bought some cerro-safe to do a bore cast and couldn't get it out of there. Turned out I had the kind that expands on cooling and it was locked in there pretty good. Had to dunk the barrel in boiling water to get it out. The expansion-neutral alloy is the one to use for precision measurements of castings. The expanding variety may be used in tapered holes like the chamber, but cylindrical areas like the chamber neck will tend to lock up a short time after solidifying (seconds). Bent Ramrod's method of tapping it out right away may work for you.

[cub45]

I used powdered sulfur from drug store, melt in pan on stove and pour in like cerro-safe.

[Hossfly]

Powdered sulfur will expand if poured into a chamber. I’ve used it to set bolts in concrete. And if you melt it in the house you wont be staying in there very long.

[ulav8r]

We were taught to use flowers of sulfur at CST for chamber casts. Worked well.

[2152hq]

You already have the Cerrosafe,
but if you are having problems using it and want to try something else,,a simple chamber cast can be done with 5min epoxy (or it doesn't have to be the quick-set type).

Wax the chamber and bbl bore for a release agent. Don't skimp on the release agent!
Again run a cleaning rod with a tight patch on it up into the bore from the muzzle to seal the bore off.
Leave the handle end of the cleaning rod some inches away from the muzzle of the bbl so you have a distance to push the rod into the bbl to dislodge the casting when setup.

Mix up your Epoxy and pour it into the chamber and let it set up. Simple as that.
The few times I used this I inserted a long slender machine screw into the epoxy right in the center and let it set up with it like that.
It gives you something to more easily handle the casting once it's out and you are examining it, but it's not really necessary.

Make the 'handle' as large in dia as you want and it'll make for less epoxy you have to mix up.

Punch the set up casting out with the cleaning rod. Clip the casting off of the patch.

The casting will not in all likelyhood be a perfect down to the .000" measurement of the chamber,,figuring in shrinkage, etc.
But it will allow a good look at what the chambering is in the bbl with little preparation and work.