I don't know if this is the stuff but I painted a car years ago and we used a product called "extends".

http://www.loctiteproducts.com/products/detail.asp?catid=13&subid=47&plid=168

it turned black an basically converts the chemical make-up of rust.

I highly recommend painting the trailer with herculiner, it's a roll on bedliner product that has served me very well.


http://www.herculiner.com/


Of course you could get it sprayed with Line-x or Rhino liner but that stuff is so expensive. The herculiner ran me a bout 100.00 a gallon but I have plenty left over for touch-ups.

Always borrow money from a pessimist. He won't expect it back.