undercoat question

I want to undercoat my truck but I don't know how many cans of spray I will need to do 2 full coats... Does anyone know how many cans I need to buy??

It's a 99 Z71 extended cab short bed.

Assuming you are using something off the shelf? I would strongly recommend you take it to a professional. Most of the stuff coming out of an aerosal can I don't think will be able to do the job right and be durable. Just my two cents.

I agree with using a pro. Although my 88 Silverado has cancer from Minnesota winters, the underside is still well coated. You usually get some kind of warranty, too. Worst after coating experience was changing the fuel filter for the first time. Gas dissolved the coating on the filter when I got it loose and it took days go get my hands clean.

http://www.magnetpaints.com/underbody.asp
I have been looking at this stuff to keep my new truck frame new. I havent done it so I dont know how well it works but it looks damn good. Check it out