Heat Safe Surface

I have a wooden painted white shelf that im going to set my ballast on. My ballast gets extremely hot... therefore I dont wanna melt any paint or burn marks. I was wondering if anyone knew of a heat safe surface that I can easily put in my shelf? I have 1mil thick Mylar? will this work? I could layer it? what do yall think?

Thanks

I rest my ballast on my metal poker case, rest it on somethng non-flamable like some bricks or cinder blocks.

Aight cool I have like 3 dozen left over bricks in my garage. Thanks for the help.