learning to torch cut

deereman75 · Jan 11, 2012

Well today I was doing some torch cutting for the first time in probably 2 years. All the torch cutting I had done then was melting my way through some rusty re-bar. I have been watching a few videos on it, and looked up the settings online. Well here it is. I was using 5 psi acet, and 25 psi oxy with an airco 00 tip. 1/4 inch plate covered in rust, spatter, and 6011 slag.
Here is some pictures of the top and bottom of the plate.

Here are some of the cut.

NOTE: no cleaning was done to the piece before or after the cut. The pictures are of two differnt cuts on the same piece.

So what do you think? Any tips? I wont be able to do any more cutting for a few weeks, since I am out of oxygen, and I wont be able to get to air liquide for a while. When I get more oxygen, I will be able to try any tips.

Shield Arc · Jan 11, 2012

I think one of the biggest mistakes people make with a torch is pushing the lever all the way down. There is a sweet spot with a torch, sometimes it is only an 1/8 th of an inch down on the lever. What you want is the cutting cone to reach out as far as possible from the tip, and have a turbo sound to it.

monckywrench · Jan 11, 2012

Check out irish fixits outstanding torch vids on weldingweb. Tips with demonstrations!

If you pull them up on Youtube you can use the Firefox downloader add-on to save them to your PC then play the files using vlc.

How to use a cutting torch - WeldingWeb™ - Welding forum for pros and enthusiasts

Mozilla Firefox Web Browser ? Free Download

https://addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/

deereman75 · Jan 11, 2012

I did watch all of irishfixits videos, and they helped my a lot. Also, the pictures I posted dont really show the cuts very well. They are A LOT smoother then the pictures make them look, and there is no slag under the cut. I did make a few better cuts, but this is just the one I grabbed. Some of the cuts looked almost plasma clean. I think they are pretty good for my first attempt.

deereman75 · Jan 11, 2012

Shield Arc said:
I think one of the biggest mistakes people make with a torch is pushing the lever all the way down. There is a sweet spot with a torch, sometimes it is only an 1/8 th of an inch down on the lever. What you want is the cutting cone to reach out as far as possible from the tip, and have a turbo sound to it.

Thanks, thats a good tip. I will try that next time I can cut. Also, what kind of torch do you use?

Shield Arc · Jan 11, 2012

I don't know the model, but it is a Victor, I'm sure the set was called Journeyman. I got it in the early 1980s.

lilranch2001 · Jan 11, 2012

Shield Arc said:
I think one of the biggest mistakes people make with a torch is pushing the lever all the way down. There is a sweet spot with a torch, sometimes it is only an 1/8 th of an inch down on the lever. What you want is the cutting cone to reach out as far as possible from the tip, and have a turbo sound to it.

Also make sure you lead (point ahead) your flame into the cut

A lot of people will have their torch head at 90 degrees to the piece when in fact 60-75 degree angle works much better

deereman75 · Jan 12, 2012

Just a side question here. How low can you let the torch tanks go? There is 100 psi in my oxy, and 50 psi in my acet. I want to get as much out of them as possible, but I heard you should always leave a bit of pressure.

RoyJackson · Jan 12, 2012

When I was cutting, my biggest problem was moving too slow. The metal would flow back together behind the torch.
Once I speeded up a bit, the cuts were cleaner.

jake98 · Jan 12, 2012

Sell that torch, get a plasma cutter! :laughing:

weldermike · Jan 12, 2012

jake98 said:
Sell that torch, get a plasma cutter! :laughing:

Cant wash with a plasma cutter, I rarely use them because of that. Good for fab work, but a pain for repair work. Just my opinion tho.

jake98 · Jan 12, 2012

I don't have too much experience, but was able to cut perpendicular pieces off with mine (PP70), no problem. Is that what you mean by 'wash'?

deereman75 · Jan 12, 2012

I found I had to move really fast to get a good clean cut. Hey my first time cuts with a torch were a lot better then a lot of plasma cuts I see at school. No dross at all. I have to say after seeing how good my beginner cuts were, I dont even want a plasma. On the bottom of those cuts it looks like there is a lot of slag hanging off, there isnt. That is a weld bead on the bottom of the piece. My dad said my first cuts were better then he has ever made. That was nice to hear.

weldermike · Jan 12, 2012

jake98 said:
I don't have too much experience, but was able to cut perpendicular pieces off with mine (PP70), no problem. Is that what you mean by 'wash'?

No jake by washing I mean feathering your oxygen flow so you can dismantle stuff that is welded together. For instance, the harder the material the quicker it heats up(the weld) so you can feather your torch and wash down a weld without cutting into and gouging your base metal. same with bolts and stuff when dealing with thin metals. Plasma cutters are good for certain things, but they only cut, thats it.

deereman75 · Jan 12, 2012

weldermike said:
No jake by washing I mean feathering your oxygen flow so you can dismantle stuff that is welded together. For instance, the harder the material the quicker it heats up(the weld) so you can feather your torch and wash down a weld without cutting into and gouging your base metal. same with bolts and stuff when dealing with thin metals. Plasma cutters are good for certain things, but they only cut, thats it.

Does one of those bent scarfing tips help for that? Torch washing would be great for removing my bad welds.

weldermike · Jan 12, 2012

Yes, I just use straight tips tho, wanna keep you torch as flat as possible so not pointing into your base metal or you can have accidental gouges. Takes practice but a real good technique once you get good with it. Saves lotta grinding, and a lot of waisted material

jake98 · Jan 12, 2012

weldermike said:
No jake by washing I mean feathering your oxygen flow so you can dismantle stuff that is welded together. For instance, the harder the material the quicker it heats up(the weld) so you can feather your torch and wash down a weld without cutting into and gouging your base metal. same with bolts and stuff when dealing with thin metals. Plasma cutters are good for certain things, but they only cut, thats it.

I hear ya (I think..) Thanks.

deereman75 · Jan 12, 2012

weldermike said:
Yes, I just use straight tips tho, wanna keep you torch as flat as possible so not pointing into your base metal or you can have accidental gouges. Takes practice but a real good technique once you get good with it. Saves lotta grinding, and a lot of waisted material

I will have to practice that when I get my tanks filled. That will be really good to know for the line of work I am planning to go into. If I see a good deal on a small airco scarfing tip, I will get it. Dont know how small they make them though.

weldermike · Jan 12, 2012

Keep in touch pal, washing takes a little practice, but ill help walk you through it. Once you get good at it youll be glad you used your plasma cutter money on other tools of the trade. For now at least!

deereman75 · Jan 12, 2012

weldermike said:
Keep in touch pal, washing takes a little practice, but ill help walk you through it. Once you get good at it youll be glad you used your plasma cutter money on other tools of the trade. For now at least!

I think the money I could spend on a plasma would be much better getting me bigger torch tanks and a dc stick welder.