There are a few companies that make these forms, we sell them with new station equipment today. Morgan Bros., Riverside Steel, Formex plus OPW has a line of them. Often bowtie or dogbone shape. I put a stainless steel one at my house which does not exactly look period correct but will never need painted either.
They may not sell direct but you can get them through your nearest petroleum equipment distributer.
If anyone around PA needs any we have some oddballs we would make a great deal on, rust included!
