Materials

I’m often asked about the materials I use in modelling.

Nickel Silver is the mainstay of my work, in sheet and bar form. Its advantages are that it works well, solders well, and has a fairly low thermal conductivity which means that when soft soldering a smaller iron can be used and there are fewer burnt fingers than when working with brass. It takes paint moderately well, certainly better than brass. The only real disadvantage is the limited availability (I get mine from Metalsmith). It is also very expensive in large sizes, so I use other materials for large items like boiler fittings and wheels.

It's also worth mentioning that I don't anneal nickel silver, or any other material for that matter. I find it is quite possible to roll it, even the "half hard" state in which the sheet material usually comes. It has some spring in it, so you have to roll it to a smaller radius and let it spring back. I just do the rolling in several stages to progressively smaller radii, rather than try to get to the finished radius in one go.

Annealling needs to be done at the right temperature, otherwise it's a bit hit and miss. When I experimented with it, I found that either the temperature was too low and it didn't have much effect, or too high and the material became so soft that it showed up every mark. I found it difficult to get it right. And without a furnace, it is also difficult to get a sheet of material to a uniform temperature, so it distorts under the differential thermal expansion.

Brass is what I usually resort to for fittings too large for the nickel silver I have available. I also use it where the prototype uses brass, because only unpainted brass looks like brass.

Mild steel and tinplate are materials that I would use more of, if only they did not rust. As I discovered to my cost, even the tin coating on tinplate does not protect against the liquid flux I use for soldering (Carr’s products). Unplated steel can be soft soldered quite successfully with the usual attention to cleaning and fluxing, but it is essential to wash it thoroughly afterwards to remove the flux residues. I have used tinplate for curved components because it has less spring than nickel silver, but now I have experience of rolling NS properly, that isn't much advantage.

Stainless steel is much harder to work than mild steel, and it and aluminium are the only common materials that are completely unaffected by flux. The only use I make of it is for clamps to hold parts in place for soldering, and for this it is excellent.

Aluminium is a material with a lot of advantages - it is cheap, readily available in a huge range of sizes, and machines easily - and two big disadvantages - it is difficult to solder and does not takes paint well. I use it for machined components that can be held in place with screws or adhesive.

Whitemetal. You may be able to solder it. I can’t, and I don’t know why. I've used it in the past to make castings in my own RTV moulds (such as the injectors for King Arthur), but I really dislike it as a material and I've pretty much given up on it.