Cutting Help

[dodgeramsst2003]

Hi,

I learned Oxy/acetylene cutting in college a few years back. I used to be fairly good at it, but recently broke out my torch set for a new project, and am having all kinds of problems. Yesterday, I made a few cuts, everything working fairly normally, but the slag was welding itself on the bottom edge of the cut. I ran out of O2 last night and had to go get another cylinder today. Tonight while cutting, I could only manage a short distance before the torch popped back and went out. the short distance that I ran had the slag welding on the trailing edge of the cut. I'm cutting 1/4" and 3/16" with a #1 tip, running 4 on the acetylene, and 30-35 on the O2, can anyone please help me out a little? I'm leaning towards it being either a cut speed, or a torch angle problem? I"m running the torch about 1/4" off the metal being cut. Any help would be appreciated, I have a cheap chinese torch, but in the past could always manage a decent cut, this time not so much.

[Jim-Tx]

I'm far from an expert on O/A cutting, but I'd turn up the pressure especially on the Acetylene. It sounds like you need to move faster and/or angle the tip towards the direction of cut. I hold my torch so that the little short cones just contact the metal. 1/4" sounds about right. Try to move at a steady rate and a guide helps also. Be sure the tip is clean and the cones are all equal. Hope this helps.

[Hotfoot]

I run my oxygen at 20 , and the acetylene at 4, so you may be blowing off more oxygen than necessary...but that's not hurting your cut...actually the oxygen is doing all the cutting...if you have someone cut the acetylene off after the cut begins, the cut will continue.

When you adjust the torch before starting the cut, the inner cone should remain about the same when you pull the trigger, then release it...that's important...also...

Start with a very hot puddle..edges are easier to start tyhe cut when beginning.

These are my personal tid bits...the opinions of others often differ from mine.

[dodgeramsst2003]

Thanks for the help. Turned O2 down to around 30, and found that even though I had the acetylene "set" to 4, I didn't actually have any tension on the regulator. Turned it up to about 5 and now have just a little tension on the screw. Been practicing holding a steady pace and things are going much better now. Its funny, I can take a mig or tig and keep a steady pace, but put that torch in my hands and I'm all start and stop. Go figure.

[hankj]

If you have a smaller tip, switch to it. For thins stuff like you are working with, I use as small as a #000 and seldom go bigger than a #0.

How are you holding the torch? Death grip? Try easing up on the grip and concentrate on getting comfy.

Hank

[Trickasabrick]

Here's a chart that may help you with some of your settings.

http://eurekaoxygencompany.com/victor.htm

Like Hank said, I think you're using too big a tip for the thickness of material. You also may be moving too slow, allowing the slag to close up on the back. You need to move faster than you think on 1/4. Here's a good resource for cutting. http://www.esabna.com/EUWeb/OXY_handbook/589oxy1_1.htm

The popping and torch going out may be due to dirty tips. It could also be your Chinese torch. I had one like that and had problems with the fire going out and popping. Got a Victor now and that hardly ever happens.

[dodgeramsst2003]

Thanks for the replys you two. I have managed to get the first bit of my project cut. I'll try and get to the store and buy a smaller tip and try that on the next phase.

Hank - I don't think I"m "death gripping" the torch. I usually hold it with my right hand using my thumb on the cutting lever, and basically cradle my right wrist with my left hand to steady myself. If I can I rest my left elbow either on my waist or on the piece depending on position. If the cut and my gloves allow, I'll cradle the torch up between the mixer and the tip but don't have my hand all the way around it, just resting in between my thumb and index finger. Unless I'm doing some sort of complex curve, I always have a guide of some sort either tacked or clamped in place to keep me on the right path. I figure that is one less lateral movement to worry about.

Trick - I"m moving as fast as I can without losing the cut. It seems that If I go any faster, I lose my cut and have to preheat just a little and then go back to cutting again. I'm looking for a different torch, just waiting for the right deal to come around on a used on as finances won't allow a new one right now.

[Roger]

Keeping it simple, O/A cutting;
Slag at top of thick plate, travel is too slow.
Slag at bottom of thick plate, travel too fast.

If your cutting 1/4" plate traveling slow can have enough slag to weld cut line with slag.