advice for cutting brackets-OxyAct or plasma?

[shaley]

I used a OA to cut these off and arc gouging to do the solid pins.
http://www.tractorbynet.com/forums/build-yourself/91529-arc-gouging-tip.html?highlight=arc+gouging
Make sure you use a medium preheat tip at least with a 00 or 0 tip. Try to wire wheel the paint from both side of the weld bead you want to cut. I used 5psi gas and 30 psi O2.

 

[72chevy4x4]

after upgrading to size #2 bottles I was back to practicing on my brackets and some 5/16 sheet metal. I used a 2" metal tube as a guide to make a straight line-which works well. The biggest problem is keeping the torch cutting. It 'feels' like I"m going slow enough, but at times it stops cutting-at which time I back off, heat and begin cutting again. Each time, it makes more jagged edges :-( Pressure is around 20psi for O2 and fuel at 5 psi. Thanks for the tip on the meaning of 'regulated'. What would the effect of greater O2 pressure be?

 

[Michael_E_Tx]

Hi 72chevy4x4.

I don't think you'll find much difference from increasing the O2 pressure, but experiment. Seems like different folks like different O2 pressures. Shaley's 30 psi seems common also. Sure can't argue with his results.

On 5/16" I would use the largest tip you have if it came with more than one. Examine the edges of what you are thinking are good cuts and not so good cuts. If you are moving at about the right speed, you should see sort of regular up and down marks on the edge, with little slag on the bottom of the edge. If you are going too slow, the cut line will tend to cave in on itself and look slaggy.

One thing you can do to keep the cut going is tip the cutting flame into the cut more. Keep in mind that although the actual cutting is being done by the oxygen flame, it is sort of critical to maintain a uniform distance from the surface. It doesn't take much deviation to disrupt the cut. I found that to be one of the more difficult aspects to master. Dargo's suggestion of knuckle or finger dragging works good. I use my left hand sort of like propping up a pool cue to accomplish same.

The last thing I'll suggest is to check your O2 flame out of the cut if you are having problems and make sure it is still putting out that nice slender long flame. Any flaring or irregularity will affect your cut. Keep the end of the tip clean and flat also.

Pretty soon, all this will be ordinary to you and you'll start to enjoy the process. Good luck.

Mike

 

[BTDT]

Gloves. Leather gloves. I know this sounds like common sense, but when your cutting and dragging your hand along to keep torch tip distance right, what I call dingleberries (hot balls of molten metal/slag) will be spewing around, and without gloves, well you know the rest.

 

[jimgerken]

I see you bought the OA setup. But for the benefit of others reading and contemplating the same questions, the plasma cutter makes an excellent gouger! Starts cutting instantly and it is hotter than OA. The smaller flame makes details better. And of course it cuts metal too, when you are done gouging. The one thing the plasma cannot do is weld, like the OA can. But the plasma runs so cheaply, it is a pleasure to have around. Give it new consumable tip once in a while, and feed it clean dry compressed shop air and electrical current.

 

[m7040]

I did not invest in a plasma cutter but still use the OA method. For ocassional use that is fine for me. If I was going to do a lot of projects I would buy a plasma cutter because of the clean cuts and little grinding required. The trick to OA cutting is consistency in position and speed. You need to hold the tip at the work just at the concentrated flame point and then preheat until a portion of metal is getting red. Then trigger the oxygen and start the cut. Now you move at a slow steady speed angling the tip slightly towards the direction of movement. By the way I go with 30-35 O2 and 5 psi A. Practise on some scraps to get the hang of it.
Also OA can be used for heating metal for bending or strightening and it can solder and weld as well. Very usefull to have around. Biggest thing is to lease bottles since the small owner bottles dont have much capacity. I lease full size bottles from the local weld shop