I picked up a used Dump trailer and want to coat the "well" worn (not rusted) steel floor and walls with not only a barrier against the manure but a surface that will be slick to aid in winter and summer dumping of the dump.

Any thoughts on products?

I would spend a few extra bucks and get the LINE-X treatment!!!

http://www.line-x.com/

LineX and other Spray in Bed liners are NOT slick.

After having trouble getting a couple of loads out of mine this winter. That's the last thing I would spray the bed with. 

What ever I'd spray mine with probably wouldn't last.  A load or two of gravel, a few chunks of broken concrete and it would be scrapped out.

There aren't many coatings that will stand up to the abrasion normally encountered in a dump bed. I've successfully used Dupli-color's bed liner material in the steel dump bed of our UTV. This is primarily used for manure hauling and has shown no wear in almost three years of use. I have also hauled sand, gravel, firewood and anything that fits into the space.

When I installed the bed liner material, I used a short nap roller that resulted in a smoother finish than a normal installation. The manure dumps easily with little residual left afterwards. I doubt that Dupli-color would be as durable if it were used for constant gravel hauling.

I have considered the same material for the inside bucket surface of my front loader. My previous loader literally rusted through, with the constant handling of manure. This one is a couple of years old now, and is starting to rust as well, now that the original factory paint has worn off. I have also considered epoxy/graphite and epoxy/aluminum materials as well as some aircraft anti-chafe coatings.

The Dulpi-Color is relatively inexpensive and is easily touched up if necessary, so it might be my next project. I have successfully used this material on other floor coatings, and it has worked well.

Gard,  I have heard (read) you discuss this before. 

I went to the website.  Is this product at Wal-Mart?

So basically you just don't use the roller they sell with it working not achieve the rough finish?  You go for the smooth finish?  What about applying with a brush for an even smoother finish? 

Slippery is better.   As my trailer will mostly haul manure.

Paul, I have sent a few emails to similar companies but no replies yet.

I went looking for the duplicolor and noticed that Rustoleum seems to have taken up that shelf space.

I brought home a gal and did a test spot and didn't like it.  It had a grit in the paint and dried flat.  So I took it back and noticed that there was a gal of rustoleum professional.

I brought that home and I smeared that all over the inside and it seems to be pretty good so far.  Glossy and smooth.

But I am definitely looking into some sort of a plastic base that will help with the winter freeze.  Just like a truck liner.