How do the larger operations prep bare steel ?

[Sampson Jones]

Im not doing so hot in the prep bare metal for paint area . I recently power wire brushed a piece that had welds , and just some cut through slits in it . I painted it flat black and set it outside . A few days later it rained on it and then a few days after that I saw rust at the welds and slits . For a small time operation what would be the best method of prep for items that will out in the elements . I was also wondering how the factories prep bare metal for paint .

[see&see]

The good factories normally use an acid based metal etch, dilute with water, spray on let set 30 min, wash off with water. It's strong stuff so use gloves. You can buy it in gallons at Home Depot..

Once the water drys, wipe off the white substance with a clean towel and you are good to paint. That acid will go down in the welds and low spots and does neutralize the rust action. If you really want a good lasting paint job use a product like POR-15 Rust Preventive Coating under the paint.

When I was just starting out I spray painted a 35' long semi end dump and it rained that night. It took me a week using a sand blaster and hard labor to get it back so I could re-paint. You never forget those kind of screw ups.