Ive heard this stuff is great but terribly harmful to humans? What is the easiest / cheapest DIY Undercoating?

 

Ospho is good for stopping rust but will burn you skin.I always use thick rubber gloves when using it
After you put it on and it sits a few hours wash it off,let everything dry then top coat it
It will rust again if not painted

 

nice, is there any objects i do not need to get it on, what kind of paint do i need to use?

 

Some directions here Ospho
If you live in a harsh environment Por15 is a good top coat
A good frame paint also works good

 

Yes, POR15 works well but it needs to be top coated if any is exposed to sun/UV rays as it will break down. If only used under the truck, don't need it.Two or more thin coats is key with POR 15. It is designed to be applied direct to metal though for its anti rust sealing properties. Definately wear gloves as you will be wearing it for a couple weeks if you get it on your skin and don't get if off right away LOL. Been there and done that!