Great Lakes Garrison & Base

I've been trying to line my TK helmet interior, I've tried neoprene liner, but unfortunately, the adhesive does not separate well and it doesn't line up well in the helmet, leaving gaps. I was looking at purchasing some knee guards, and cutting them up to use as just a padding, I'm curious to hear what members have used. My apologies for the frequent questions, I'm very new to costuming.

For my clone, I used air conditioner weather stripping foam. Comes in 1 and 2 inch thick strips. Glued them in with E-6000.

I just use blocks of sheet foam to position my head in place inside my TK helmet.