Best Material for Locomotive Frames

[dcutting]

If you could make a locomotive frame out of any material, what would it be? Lead? Bronze? Zinc? Steel? What's the best material in your mind? I've got a decision coming up soon here about a new toy I'd like to buy for CESM and this is the last major question yet to be answered. 

David

[Missaberoad]

Considering no other issues Tungsten... That being said, it is not an easy material to work with and mass production would likely be impractical...

I imagine a cast zinc alloy or a sintered bronze would be the best options to look at...

[C855B]

What he said. Tungsten. Seriously. Tungsten loco frames would change the world.

But knowing W is all but impossible to cast, sinter or machine, my next choice would be brass for ease of machining, followed by bronze.

[dcutting]

What about for lost wax casting? That's the direction I'm going in here.

[daniel_leavitt2000]

For lost wax you are looking at either brass or pewter.

[C855B]

If you can consider brass (or bronze) in the process you have in mind, that would be my choice. Common brass, at ~8.5g/cm^3 is about 20% denser than zinc or tin (pewter is 90-95% tin).

[wazzou]

For lost wax you are looking at either brass or pewter.

Pewter and Brass would be too soft wouldn't they?  I'm sure Pewter would be.

[Nick Lorusso]

Look into the same materials atlas kato imrc.

[C855B]

Pewter and Brass would be too soft wouldn't they?  I'm sure Pewter would be.

Pewter, yes, brass, not really, although it depends on the ratio of zinc to copper. Hobby brass (K&S) is "cartridge brass", 70% Cu and 30% Zn. It's fairly stiff and hard while retaining reasonable machinability.

As far as copying the alloys the major manufacturers use, they have other priorities, especially mold life since they're not using a lost wax technique. I personally am not happy with the recent frames ever since the reformulations to eliminate lead. The frames are noticeably lighter and pulling capacity dropped significantly.

[wazzou]

Pewter, yes, brass, not really, although it depends on the ratio of zinc to copper. Hobby brass (K&S) is "cartridge brass", 70% Cu and 30% Zn. It's fairly stiff and hard while retaining reasonable machinability.

Brass isn't very heavy though, is it?

[Kentuckian]

Depleted uranium. 

[dcutting]

Pewter, yes, brass, not really, although it depends on the ratio of zinc to copper. Hobby brass (K&S) is "cartridge brass", 70% Cu and 30% Zn. It's fairly stiff and hard while retaining reasonable machinability.

I think another name for this stuff is yellow brass. Try looking up red brass and silicon brass, those are two other common types it looks like.

[peteski]

Brass isn't very heavy though, is it?

Brass is heavier than the alloy currently used by manufacturers, and I believe even heavier than steel (but of course lighter than lead or tungsten).

Lead is heavy but soft, but I am pretty sure that Kato GP38-2 chassis was made from lead or some alloy containing mostly lead. That was probably the heaviest Geep ever made in N scale.

[GhengisKong]

I always liked how heavy the first gen Kato F3/F7's had the best frame material. If you have any friends who have access to an x-ray spectrometer you can find out what metal % the kato frames had.

[dcutting]

Must I worry about brass corrosion over time? It looks like the best material so far plus it's fairly common and relatively cheap. The only other thing I can think of would be silver. More expensive, but for small frames it is much more dense than brass. Maybe as a "premium option"