Coating on New Steel

admin

I feel dumb for asking this question lolOn new steel, the blackish coating that comes on it when new, do you have to sand all that off to totally bare shiny metal before priming & painting?  I'm talking on tube or sheet metal.
Reply:It has been my experience that you do if you want the best finish, if you are just after rust prevention, then no.
Reply:It depends on how 'good' you want the paint job to be and how attached that black coating is to the steel and how clean of oil and crud you can get that black coating.That black coating is mill scale by the way.  The best laid schemes ... Gang oft agley ...
Reply:I am building my first project, a welding cart made with 1"  .100 wall square tubing and I was able to easily strip all the coating off it.  But on the sheet metal I am using on it as well I tried and it won't totally strip off.  On a 12" x 4" piece I've gone through 2 40 grit flap discs already and only done 1/4 of it.
Reply:I just degrease and paint, never bothered to remove the coating...Synchowave 180SD  Bernard 3500SS water coolerMillermatic 200Parker Plasma Tec 40dvOperating Engineers Local 12
Reply:What is good to use for degreasing?
Reply:acetone
Reply:Originally Posted by DaveJeepWhat is good to use for degreasing?
Reply:Is water based paint thinner OK?  Or will it leave residue?  Like this stuff http://www.homedepot.ca/webapp/wcs/s...k=P_PartNumberAcetone is just so expensive here.
Reply:Isn't it acetone that generates phosgene when you heat it? TSP would be the safest, cheapest way, you can buy the powder from HD, mix it up with water and it will clean the grease off no prob. It is in the painting aisle.
Reply:What does TSP stand for?  Never heard of it before, new to this stuff lol
Reply:Trisodium Phosphate, it's been around for quite a while........Synchowave 180SD  Bernard 3500SS water coolerMillermatic 200Parker Plasma Tec 40dvOperating Engineers Local 12
Reply:Originally Posted by salem747Isn't it acetone that generates phosgene when you heat it?