Welding with new steel.

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I got about 150 feet of new hot rolled steel , it's not rusted at all but it also doesn't seem to be grounding very good for my welder to keep a steady weld going.   I've noticed after wire brushing a place for the ground clamp on the metal and also wire brushing the small areas being welded it seems to weld much better.    What's with the surface of new steel? Is there anything else i can do besides wire brushing or grinding it all the time?
Reply:It's called "mill scale". Do a search using that term- lots of posts here.A few weldersA lot of hammersA whole lot of C-clamps
Reply:i always try to get shiny metal for the ground to clamp to.  new metal or not
Reply:Read this and all will be explained:http://weldingweb.com/vbb/showthread.php?t=76301kidtigger24  They think I’m crazy, but I know better. It is not I who am crazy. It is I who am MAD!
Reply:Thanks for the link. Now can i paint over the mill scale as long as it isnt flaking and clean?
Reply:If you want to do a good job you have to get rid of the millscale for welding and painting.Grind the millscale where you're welding and sandblast the millscale before painting.I've known lots of people asking this exact question and not doing the right thing to do because it's to much work.But this is the right way to go about it, grind and sandblast.
Reply:Run a plate test for and inspector and neglect to grind the mill scale off the backing bar and you will know about it. Run good and hot and you may boil it out, but on x Ray it will likely show you why it should be removed."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:I test soaked some parts in White Vinegar for 14 hours.The Mill Scale came off pretty easy, you can see the difference. I cleaned them with Windex and I sprayed one part down with WD40 and left the other one as is, I want to see how aggressive the rust gets.  Need to find how much time i get before they need paint.
Reply:Originally Posted by HOBARTi always try to get shiny metal for the ground to clamp to.  new metal or not
Reply:Not everyone can afford the time or money to sandblast completely for paint, will give the best results. I usually clean the weld areas down but for paint, wire brush it, then wipe it down with laquer thinner or Acetone then primer and paint. Never have any problems with the paints not sticking."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Originally Posted by kolotNot everyone can afford the time or money to sandblast completely for paint, will give the best results. I usually clean the weld areas down but for paint, wire brush it, then wipe it down with laquer thinner or Acetone then primer and paint. Never have any problems with the paints not sticking.
Reply:Originally Posted by Titan UpI test soaked some parts in White Vinegar for 14 hours.The Mill Scale came off pretty easy, you can see the difference. I cleaned them with Windex
Reply:Originally Posted by kidtigger24What do you use for a primer? Some type of etching primer?kidtigger24
Reply:Using a red oxide primer is about the best way to go.  I never sandblast, at most I maybe wire brush loose rust if the thing has been sitting for a while in the weather.The most important thing is to get rid of any oil the shipper has applied to prevent rust during shipping and storage.  The oil will interfere with the paint adhesion.Van Sickle is about the best I've come across.  I have stuff that's been painted around 10yrs ago, and is still rust free.http://www.vansicklepaint.com/tracto...tomcolors.htmlAgain, I have to stress.........get rid of any oil on the steel.  The other stuff is mostly cosmetic."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by sn0border88Nothing about those pieces looks clean.  Vinegar and Windex is not an appropriate metal prep. Just get a grinder and do it correctly.
Reply:Try some bleach or mollasis they also work well for rust removal, not sure about mill scale though....Lincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st