I have a project where I need to modify the helmet foam to get a better fit on an odd shaped head. I have looked on the web for fit kits and such, but none will meet my needs very well. I was hoping that someone here might have a good idea where to find the urethan foam with laminated wicking / antimicrobial fabric like you see in batting helmets and for that matter the whole aisle of helmets at the sporting good store. I would likely need less than a square yard depending on the thickness.

I k now it is probably a mediocre idea at best to fiddle with a helmet design, but I need to bulk up the sides to keep the helmet from fitting floppy from side to side.

Your best bet may be helmet fit kits for things like skateboard and bike helmets. I have kept such extra pieces over the years to fine tune helmets of all kinds. Worst case you could find a thick mouse pad and cut strips from it if necessary.

It all depends if you are looking to fine tune .125 or something like .75 inch.....

Hope this helps.