Mini Fridge Ferm Chamber question

[greenacarina]

OK, so I got a mini fridge to use as a fermentation chamber (using it with an ST-1000 temp controller).
I did a little surgery to the hump....unbolted the compressor, moved it back, then notched out the hump (about 12" wide x 4" deep).
I built a partial box out of some roofing flashing and pop rivets, attached it to the underside of my cutout, filled it with spray foam, then cut it into shape so all the sides are flat.
First, thanks to all you guys for sharing your projects!! I wouldn't have done it this way otherwise.
Second, here is my question- What should I use to cover the exposed spray foam? I was thinking maybe some rubberized undercoating (automotive)?
What have you guys used??

Thanks
Chris

 

[greenacarina]

OK....so spackle and bumper stickers it is.

Thanks

 

[noggins]

bob marley poster.