Prism7guy's track car

[Prism7guy]

The undertray is made out of 10mm thick corrugated plastic, the sort of stuff that's used on conservatory roofs.
I mounted some ally plate to the old brackets that held the spare wheel in place to secure it at the front, and simply bolted through the lip under the bumper at the rear. I used some epoxy to hold some ally flat along the length of it where it was being bolted to give it extra strength, and made some little 10mm long aluminium spacers to sit inside it to prevent it from getting crushed when i tighten the capscrews.
A few pictures to try and explain better.