Porosity on the back of an OA cut

Cutting too slow which melts more metal than necessary. O/A slag can be quite maleable which can make it very hard to chip off. This can also be caused by using a larger tip size than required.

It is one of the reasons why I prefer cutting with Propane. Propane slag is much more brittle and chips off easier.

You can also try using cutting guides. Any heavy bar of steel is fine. By resting the cutting head against the bar while dragging you can make a more consistent cut which can make it easier to chip.

What am I doing wrong to get porous spongy hard to remove slag on the back of OA cuts?

Tips appreciated.

Steve

Over cutting. Using too large of a tip, too high of an oxygen pressure, too far of a stand-off, or traveling too slow.

OO Tip, 20# O2, cutting 3/8", standoff blue tip length, so must be too slow.

Am gonna play with it, plus find me a chart to give parameters.

Steve

Your tip is too small. #00 is for sheet metal, 1/8" tops.

Got to a #1 tip, 40-50 psi O2, 1/2" stand-off.