Bob,

A couple of suggestions:

1) You might try a truck weigh station on an interstate highway. Sometimes they are sympathetic and helpful, sometimes they are not.

2) Most scrap metal yards sell scrap metal by the pound ... you drive in and weigh your car, pick up your scrap metal, then you weigh your car on the way out so they know how many pounds of scrap metal you bought. Their scales are quite accurate and most of these guys are pretty helpful.

Good luck!

Alvin