Plain ole poly bubble wrap sleeves. If you want something supplementary to this, get pre-made velcro lens wraps. The case dividers can be improvised with styro fome-core board etc. Urethane foam should only be used for temporary shoot location transport. Case manufacturers like Halliburton and Pelican include diced foam you can pluck to shape yourself. Cutting it can be done with a bread knife or specialized power foam cutter (quite expensive). True closed-cell foam that thick would be quite heavy, but you could hypothetically get an inert type if you could afford it.
Bookmarks