Cerro bend is a very dense, heavy metal with a low melting point (158 degrees f) which is useful for adding weight to locos. I have some and am planning to add some poundage to a couple of brass locos. But I need some input from you have tried this. What are the pitfalls? Is there are chance of damaging the engine? I vaguely recall hearing that CB tends to expand while cooling. Is that true and if so, how much? Also how do you melt the CB while controlling the temp, keeping it low enough to avoid damaging solder connections in the loco? And how do you control the flow of the molten metal so it goes where it should and not spread into areas where it could be a problem? Does anybody out there have experience with this, or am going to be a pioneer?
I’ve never used Cerrobend, but information about it is available from many web sites. Wikipedia provides general information about its uses and composition.
Cerrobend is very easy to use. Best way to melt it is in a tin can or Pyrex glass in a water bath. Put the water bath on the stove at VERY low heat. You can make molds or dams to control where you want the cerro to go, out of just about anything (balsa, cardboard, styrene, aluminum foil…The cerro is not going to be nearly hot enough to melt any solder connections, but (being metal) you need to keep it away from wiring, connections, moving parts, etc. It is also probably not going to be hot enough (or for long enough) to affect plastic parts. After you have poured it, you can “edit” your casting with a WARM soldering iron, if necessary.
George Allen pioneered the use of Cerro Bend half a century ago, including casting passenger car sides in cardboard molds. Check the Model Railroader publication index for his article - it was part of his ‘Tuxedo Junction’ series.
At about the same time, someone else recommended Cerro Safe - slightly higher melting temp, but allegedly didn’t swell or shrink when changing state.
Honesty check time. I have never tried making molds or otherwise using either of these materials, and have no connection to or business relationship with the manufacturer.
Chuck (modeling Central Japan in September, 1964)
I don’t know what the coefficient of expansion is, but one of the uses of the stuff is to make casts of rifle chambers to identify unknown calibers, and it tends to pop right out when a dowel is inserted from the muzzle and tapped, so I doubt that the expansion would be enough to pop any boiler seams. My objection to it is it’s horrendously expensive! I ballast brass steam engines by cutting a length of copper pipe to fit inside the boiler and then filling it (on the workbench, not in the engine) w/ lead.
I used it to weight 6 Custom Brass NH 1-4 Pacifics, 6 CB I-5 Shoreliners and 2 NH EP-3 Box cab electrics. They became wonderful pullers. The trick is to keep them dead level when pouring to insure that the weight is spread evenly over the drivers. NEVER us a ladle and torch to heat, the hot water in a glass pitcher works best, but it might stick to the glass so don’t use your wife’s prize measuring cup. I will be casting some truck frames soon and use Delrin Bushings to minimize wear in the bearings and provide free rolling.
I used it to weight a factory-painted brass Pacific once. It worked great! The only problem I had was that the stack provided an open hole in bottom of the inverted boiler, and I didn’t realize that until the metal was running out and all over the counter!
But once I plugged the stack the pour went well.
Thanks, everybody, for the comments. Now I have a much better idea of how to proceed.
that sound like somthing i would do[(-D]
I have never used it myself but I have known people who did; I have known many who swore by it - except related to its expense I don’t think I have ever encountered anyone who swore at it.
Just an in case. If you are planning to bake your paint on (A good suggstion with Scalecoat), you might want to wait to install the weight until you are done. I know of one engine where the Cerrobend, Cerrosafe or Templow was a small puddle on the bottom of an oven.
Rick