Excessive Slag on underside of work piece - PLS HELP

**Firefightaz** · 11-10-2010, 10:11 AM

I am cutting 18g cold rolled steel with the 50amp torch. It seems to me that on some cuts there will be no slag at all on the underside and other cuts have excessive buildup underneath. I dont change anything about the way I am cutting.

How do I reduce this slag underneath. Air pressure? Amps?

**Gadget** · 11-10-2010, 10:57 AM

Hi Firefightaz and welcome to the forum. We like pictures here so be sure to include some showing your work. Also, check out for the contest here. The odds of winning a great new Longevity machine are very good. Please post a bit about yourself in the introduce yourself section so we can get to know you.
On thin stock I find the speed you cut has a lot to do with the slag, too slow you get more. Your air pressure should be between 65 and 75PSI and the CFM of your compressor has to be enough that you don't lose pressure while cutting. I would set the amperage to the lowest you can and still cut the material. Too much heat will cause a larger kerf meaning more slag.
Dan

**KHK** · 11-10-2010, 11:12 AM

Keep the tip at a constant height above the work, if you are using a roller type tip height, the angle of the torch handle can change the tip height. Keep the tip clean, checking it frequently.

**Bluesman** · 11-10-2010, 11:35 AM

99% of the time that dross can be removed very easily with a pair of needle nose pliers. Everynow and then I have a lot of it on the backside of a workpiece after I cut it with the plasma and that is how I remove it.

**SICFabrications** · 11-10-2010, 01:04 PM

changes in moisture content of the compresses air will cause more dross (the slag stuff) there are too many variables to point your finger at one thing. torch speed and angle also play key parts in running plasma... if it is random as you claim, then i would look at the previous 3 things : moisture, angle and travel speed.... even the slightest change in those will cause you a headache

**Ascinder** · 11-11-2010, 06:22 PM

I was cutting some 14 gauge aluminum and had the machine on about 25 amps. Seemed to be perfect. Almost no dross at all. I was using a wheel for torch height and a guide for straightness, and the cuts were almost flawless, I think a lot of it would have to do with cutting angle, speed, power and air pressure as mentioned before. It's something you have to play with a little before getting it dialed in just right.

**ISKI** · 11-12-2010, 01:34 PM

I second using a torch handle holder. It helps keeps things constant. I use a holder with four wheels to keep the torch angle constant in both directions.

**Firefightaz** · 11-23-2010, 12:38 AM

I would love to use one of the torch holders to keep the tip off the work piece but I do not have a pilot arc.

**tigqk** · 11-23-2010, 02:13 AM

Use a chipping hammer to knock the dross off and experiment with different pressures and check your consummables to make sure they are tight,Longevity sells a standoff roller which is the best priced unit on the market.