Display supports for knives

[BigAl62]

I picked up a glass front shadow box with horizontal shelves. I want to display several fixed blades in it. I bought a poplar dowel that I intend to cut into short pieces and saw cut a kerf to rest the blades in. I’d like to spray paint the blocks black so they disappear in the black interior of the shadow box. My concern is whether there would be any long-term effect on the carbon steel from the wood or the paint? I’m open to other ideas too. How do you support your knives?