How to protect cushion from fireplace

I have a gas fireplace. I also would like to keep this cushion on the hearth so people can sit there. I've had it on there with the fire going, and I pull the cushion out a couple inches, and it gets warm to the touch. But that concerns me, so I'd like to put a protective C-channel on that back edge of the cushion. (If I get it skinny enough it will still fit under the open doors.) So I'm trying to think of something like that that is an insulating material - would not get hot, and would not allow heat to pass through to the back edge of the cushion. Aluminum would work, right? Something like this?

Aluminum Channel 6063-T52 Architectural 1.5" (A) x 0.5" (B) x 0.125" (t) x 0.125" (t2) - Buymetal.com

See pics: https://goo.gl/photos/c2279mVNFyopCxGG7