Another stupid question.....

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I plan to place a 12" x 12" steel plate on top of a wood work bench to use as a temp table. Is the ground clamp adequate if clamped to that plate rather than the work piece itself? If so, am I correct in assuming the workpiece should be clamped to the table plate to ensure the circuit works? This would be helpful in welding smaller pieces for sure. Many thanks.Daniel 5:23
Reply:It is ideal to clamp the ground to the work piece.  However, it is not uncommon t clamp to a steel table where the weldment rest.Make sure your part makes good contact at all time to the prior to welding. Removing scale form the plate would not be a bad idea.  Arc will occur between the plate and weldment, if good contact is not maintained.  The arc cause  marring to your metal and sometimes fuse to the plate.I work on steel tables where the ground is clamped to the table 99% of the time.  Marring is a consideration if cosmetics or fit/rolling (bearing races) applications is important.so, yeah clamp the work to the plate if possible.
Reply:Times two what tapwelder says. Most times it's desirable to clamp the smaller pieces to the table anyway. Always try to do what's best for the weld results. Get sloppy or in a hurry expect some erratic results.
Reply:Originally Posted by tapwelderRemoving scale form the plate would not be a bad idea.
Reply:New plates are almost always covered in an anti rust oil or similar substance, a little acetone on a rough rag should do, a bit of sanding or grinding wouldn't hurt.
Reply:Most new steel is P and O.  (pickled and oiled)DennisThermal Arc 185-TSWMillermatic Challenger 172VictorO/AAtlas Craftsman 12 by 24 LatheEsab PCM-875Wholesalem Tool Mill-Drill
Reply:Mill scale, the gray coating formed during processing of hot rolled steel.  Scale forms when steel is heated to a certain temperature. I think about 1800F. Anyway,  Compare the cut edge to the top of the plate.  The cut edge might be shiney,metalic or even rusted looking while the top might be gray.  None of the hot rolled stuff I purchase is oiled.  Remove scale with a electric brush or flap wheel.    If metal is cold rolled, then oil will be the problem no mill scale.  I use degreasers, or even liquid detergent to remove oil.   Acetone work well and it dries quickly. However if you have a large volume of stuff then it can get expensive.  I soak most stuff rinse and air dry.By the way, hot rolled is cheap and will suffice for probably all of your welding projects.Last edited by tapwelder; 02-04-2008 at 02:22 AM.