in an alternative embodiment the flake material can be bonded into a flexible resilient form incompletely cured foam as the binder instead of precursor powder or by making the flakes of incompletely cured foam and eliminating the binder these two methods are simpler and foam densities as low as 0 6 lb per cubic foot can be achieved with some sacrifice in product strength the mixture containing precursor powder is then placed in any suitable mold as shown in box 40 the mixture is heated to cure the polyimide precursor as indicated in box 42 and stabilize the final foam product if higher density is required in the final product the material may be compressed to a suitable extent prior to the final heating step as discussed above any suitable materials may be bonded to the finished foam or any suitable post forming treatment may be given to the foam as indicated in box 44 if desired other materials such as protective surface sheets may be placed in the mold prior to introduction of the mixture to provide simultaneous forming and bonding the final product is uniform has no voids or other discontinuities has no rind and has a selected low density the following examples detail certain preferred embodiments of our method parts and percentages are by weight unless otherwise indicated about 300 grams of monsanto 2601 34 skybond 34 polyimide prepolymer resin is mixed with about 1 by weight dow corning 193 surfactant the resin is rolled onto glass plates and dried with warm air at about 150 u00b0 f the dried resin coating is scraped off the glass and ground to a powder in.