I am a voiceover artist and need to travel with my gear. Looked into custom cases to hold them and it was… a lot of money. So, bought a sturdy but cheaper case and built the custom insert myself using foam board, wood, felt and veneer for a finishing touch. I iterated a lot and moved away from upholstery foam to foam board cause I didn’t have the equipment to get clean cuts on the upholstery. (I figured out how to get clean cuts on upholstery foam AFTER the project was finished.) If I have to make another one will probably start by making a wooden top and bottom, then cutting upholstery foam to fit and covering edges with felt.
EDIT: So, someone asked how to get clean cuts on upholstery foam. Well, you could do hot wires and buy pro equipment but the cheap, DIY method is an electric knife (the type you carve a turkey with - $30 at Target). If I were to do this project again, I would do cut-outs out of wood, then glue a top and bottom over some upholstery foam. Using the cut-outs as a guide, I would use an electric knife to make clean cuts of the foam. Then cover the inside of the cut-outs with felt.
Now, in this iteration, I did cover inside the cut-outs’ inside edges with felt to cover the foam board edges/wood and protect equipment. Don’t forget to account for that when you are measuring cut-outs!)However, if I did it again, I would experiment with only covering the non-wood part. It’s just difficult to get the felt to adhere cleanly by hand when you have to be that precise. To do that, I would probably have to make cut-out templates that account for the felt to cut the upholstery. That way, the upholstery will be slightly bigger than the final wood topping, allowing the felt to nestle in perfectly between the wood top and bottom and giving a really clean look. The only draw back to this is your equipment will hit up against hard wood.
Another tip - I did a couple of test cuts on cardboard to make sure I had the sizing right prior to final cuts. Hope that helps!
for a practical project that suits a specific need.