Last July, I fabricated hard oil lines from aluminum tubing and fittings. I discussed this with William and Dan while at Oshkosh. They said that aluminum would probably be OK, but the best practice was to use Stainless Steel tubing in this application on an engine.
I am not an A&P like William and do not have the engine experience of either of them, but I do recognize good advice when it comes from a lifetime of experience. So, I decided to exchange the aluminum tube and fittings for Stainless Steel tube and steel fittings.
The tubing is 3/8ā O.D. X 0.028ā wall, T304/304L from Online Metals. The fittings are JIC spec. from Discount Hydraulic Hose. The total material cost including shipping was $66.37, with $26.16 of that being shipping cost.
The Stainless tubing is significantly harder to bend than aluminum, but it was completed with standard hand tools.
Iām happy with the results, and feel better about using the best practice rather than something that would probably be OK.