Spring steel finishes and coatings

I'm working on my first EDM slot car chassis and will be using 1095 blue tempered polished steel sheet. However, none of the commercial EDM chassis have a polished blue surface. So I've a question for you machinist, metal working, tool and die guys out there that know a heck of a lot more about metals than I do.

What economical metal finish (plating, coating, polishing) process would you recommend...and why? I'd like to get a feel for each of your recommendations in terms of the following:

1. Cost
2. Solderability
3. Cosmetics (scratches on blue polished steel are very visible)
4. Rust resistance

Thanks,

Jeff

Here is an example of what I'm building:

If you electroplate it, you will have to bake it afterwards to remove hydrogen embrittlement. This is presumably thin material, which means embrittlement is more of a factor than in a thicker piece since the percentage of penetration is greater relative to total thickness. Even with a thick piece it can be a problem by mmaking a starting point for a fracture, but a thin spring is worse.

Something like electroless nickel may be an option. I don't have experience with it, perhaps someone who does will comment.

I haven't used any of the newer cold blues, but my experience with earlier ones was not encouraging. I need to blue a rifle and am going to the old hot blue, even though it is a lot more trouble. You may be able to find a gunsmith already set up who will do it.

Bill

I'm working with 0.042" sheet stock. I'm mostly concerned about very visible high contrast scratches in the blue tempered finish and surface rust on the raw material and pieces I get back from the EDM shop. Soldering acid needs to be washed off the assembled chassis, so I'll be applying a light coating of oil to prevent rust before I bag it. Any dull or satin finish is good enough for my purposes as long as it can be soldered.

Why not just bead blast? Then give it a coat of clear lacquer or enamel.

ENC or any of the nickel coatings won't let solder stick. Copper plating would look kinda neat! No acid required for solder!
JR

I got really into slot cars for a bit (for like 15mins ) so I don't know much about them besides the basics of some vintage cars I have.
Would gun blue work?

If you blue it, you add a oxide layer. And that can't be soldered. Flux will have to remove it and if it is a good layer, flux will fail.

So what do you want? An oxide layer or a layer that makes soldering easier?


Nick

Nick,

I don't require an oxide layer. I'm just looking for a 1095 or 1085 tempered, hardened spring steel that isn't delivered to me rusty from the EDM shop after my pattern is cut from the 0.042" sheet. I'd also prefer that scratches from the manufacturing process are not highly visible so the chassis kits are more appealing to the eye. Any coating/finishing added to achieve those two goals should not impede soldering.

I've read that CS80 has been used for slot car chassis in Europe but I have a chassis that is a bit harder...so I'm looking into 1095 or 1085 material.

- Jeff

If the metal is scratched during manufacturing, you may need to look into some type of blasting, tumbling, or polishing. Plating might mask small scratches. For solderability, I would look at tin or copper or maybe even zinc plating (with no chromate).