Aluminum body with steel tube structure, questions

[alsfarms]

I am about to embark on building an aluminum body speedster with a steel tube structure. I decided not to use wood for weight reasons. My first question: What should I do to stop galvanic corrosion between the aluminum body-work and the steel tube structure? Second question, how much contact should I have between the body shell and the structure? I am sure the more contact the more squeaks while in operation. I hope to hear from someone who has "been there-done that".

Al

[Rusty_OToole]

This is the "Superleggera" body construction used in Italy in the late 30s. They put felt between the steel frame and aluminum body panels to control squeaks, rattles, wear and corrosion.

Land Rovers had aluminum panels over steel framing with linen cloth in between.

I don't know what you could do, possibly today there is some kind of plastic material you could use. It would be practically impossible to totally prevent contact, and galvanic corrosion will occur. Perhaps some kind of zinc sacrificial anode would help prevent bimetallic corrosion.

Registro Internazionale Touring Superleggera - Body shop's History

Edited January 19, 2013 by Rusty_OToole (see edit history)

[Guest]

The fisher body manual suggests using friction tape to remove squeeks in their wood framed bodies. The tape is easy to buy and would be easy to apply to the tubing before you attached the panels. It is relatively cheap too.

[paulrhd29nz]

Have your steel tube frame, Powder coated. Have all your mounting holes drilled. The powder coating gets every where and is not an expensive process.

[alsfarms]

Thanks for the responses. I have given some thought to going with power coating the steel tube structure. That would protect the structure from rust and isolate the steel from prolonged contact with the aluminum. I do think I would use a non moisture absorbing tape to stop squeaks and rubs. Now for another question. Which type of aluminum is the best for forming and most resistant to work hardening. Work hardening results in stress cracks, that I sure want to minimize. If anyone else would like to add to this conversation, please share.

Al