fiberglass floor pans

any one have tips on makeing fiber glass floor pans? Not the trany hump, just the front part under the seats and under your feet. I'm thinking i can get some plastic sheeting 4x8' 1/8" thick sheet lay it on the existing rusty sheet and use a heat gun and slowly form it to the contor of the sheet metal. Then lay my fiber glass sheet and reson and pop rivit and glue it to the good remaining metal. Also run some 1/4" flat stock some how for the seats to bolt to.


bad idea.