Originally Posted by Dave Patterson
Thanks pdwiley. Discount steel lists there hot rolled mild sheet a being lightly oiled too so I assumed this was the way steel is commonly sold. The pickling is just hydrochloric acid I believe. I haven't found wheel abraded or preprimed sheet in the Mpls. MN area. The pickled is priced the same as the hot rolled... approx. $140 for a 4'x9' sheet of 10 gauge. Any other opinions would be appreciated. Great website!
I'd advise going and taking a look at it. If it's free of mill scale, and you can't get the primed plate, buy it in preference to straight hot-rolled. Sand/grit blasting is dirty, time consuming, expensive and outright forbidden in a lot of places. You've got to get the mill scale off or you're asking for paint failure and endless troubles. At worst with the pickled & oiled you might need to soda-blast it but this is MUCH more environmentally acceptable and a lot faster then getting hard mill scale off of hot-rolled plate. We've used the soda-blasting to remove epoxy paint off an aluminium hull when we decided to strip it back.
Most likely the oil will come off with a good detergent wash and if there's a VERY light rust-bloom afterwards, the 2 pack epoxy primers like Jotun Jotacote go over it without any problems. Better if there's nothing except clean steel of course.
I'm using hot-rolled plate but every sheet is going through an industrial blasting & priming process before I weld it to the hull. It's expensive but a lot cheaper then blasting & priming the entire hull when finished. I couldn't get pre-primed steel or pickled & oiled steel anywhere.