I can chime in here as George and I "play" on Sat in my shop. We've been doing this for several+ yrs welding anything we could get into the forge. We've certainly welded and wasted more good steel than we'd ever like to admit, but it is all good as the learning experience has been amazing. That being said, MS Bob Kramer's demo at Mt. Hood this past Aug was a turning point for both of us. Bob used a kerosene soak prior to welding his billet in a forge that everyone would have guessed could've never been hot enough to weld in...but it did! Then we read that MS JD Smith welded w/o anything, including grinding the mill scale.
That through down the gauntlet, so we had to try. Hey, it works! We weld at at 2330 plus or minus after a soak for 10-15 mins with a light hit, then reheat and hammer a little harder. On the 3rd heat, it's good to go. We've made 'w' patterns w/no problems.
Dry welds can continue with grinding the forge scale off from there.
John
www.gearhartironwerks.com