[Chips O'Toole]

I am trying to take the ears off an old-style Kubota bucket so I can weld a quick attach mount on it. I have three tools available: a plasma cutter, a big Metabo grinder with Walter disks, and a Victor oxy-propane outfit with a size 1 torch.

I would guess I want to get through 3/8"-1/2" of steel, without burning holes in the bucket under it.

The plasma cutter is probably not going to fit in the tight 90-degree corners where I need to cut. The grinder will probably work if I don't mind spending several hours cutting.

I have never used the propane cutter before. I have heated things, but I have never cut. I ordered several cutting tips. I have 3-GPN and 1-GPN. The 3-GPN tips fall out of the torch, so they appear to be the wrong size. That leaves me with 1-GPN.

I am having an interesting time trying to get a cutting flame. I read I should put the O2 at 40 psi and the propane at 5-10 psi and then adjust things until I get a 1/4" blue flame. I thought I was doing this, but the torch didn't cut. Holding it half an inch off a piece of steel scrap, it melted it but did not cut.

HELP!

[Chips O'Toole]

I looked up my outfit. I have a CA2460+ cutting attachment.

[Chips O'Toole]

I watched a video, and I think I may have it working. The guy said to create a 2.5" star pattern when pressed up against metal, so I did that, and then I cut a piece of 1/8" bar.

It looks like this is not much like plasma. As soon as you get a plasma arc, you pop through the work, and the air blows the metal out the other side. This thing appears to simply melt metal, which then goes wherever it wants. Is that about right?

I am wondering if I should have gotten a size 0 tip.

[cj737]

A 0 or 00 would be my choice.
My rule of thumb is a ratio of 6:1 or 7:1 for Oxy to Acetylene.

To get a good cutting flame, you want 1/8” long blue tips at the torch with feathery ends from the flame. You’ll need to work the flame over the material to preheat it a bit.

Excessive dross is symptomatic of the incorrect flame ratios or too slow a travel speed.

Learning to cut with a torch takes heaps of practice to understand which variable to adjust (fuel pressure, oxy pressure, flame mix, torch angle, travel speed etc).

Also, the torch tip size has a recommended fuel pressure and oxy pressure rating so determine that and heed that for best results.

[Chips O'Toole]

So basically, it's a pain to learn. Makes me appreciate plasma. I will keep at it.

Thanks for the help.

[cj737]

So basically, it's a pain to learn. Makes me appreciate plasma. I will keep at it.

It’s a pain to learn over the internet. But what part of welding and fabrication is “easy”? It’s a super technical skill and those who think you can buy a piece of equipment, plug it in, and weld/fabricate/cut like you’re pushing a vacuum cleaner need to re-think their objectives.

Also, what you’re tinkering with is quite dangerous. Unlike Argon which is inert, Oxy/Propane/Acetylene is NOT. Highly combustible and very, very fraught with danger. A plasma is more a “plug and play” tool. Good ones cost real money as do their accessories. Cheap gear might get you by, but the cost to replace a crappy unit exceeds the accessories pretty quickly.

Maybe you don’t need the added gear. Cut what you can with what you have, then grind the rest off or cutoff wheel the remainder. I’ve spent plenty of time with a grinder when my cutting tanks were empty and the LWS was closed. Sure it’s a pain, but it’s a lot cheaper than a piece of gear.

[Chips O'Toole]

Of course, you are right.

I was feeling pretty crabby last night. I thought I was in for a one-hour job. Then I couldn't get anywhere with propane. Then I had problems with plasma, which is usually very easy. And I set my hair on fire a few times and also had to put out a cardboard box which was too close to the bucket.

Then I found out Hypertherm had new attachments that might help, but I would have to get a $500 torch to make them work. That was the final poke in the eye.

I am determined to have a better attitude today.

[Gdarc21]

So oxy propane and oxy acet are similar, both are thermal cutting. They both heat steel to a glow and the you press lever and the centre hole is oxygen only, and it oxidizes the hot steel, in general kinda blows it away neatly. With both processes make sure that you light gas first. Turn gas knob on handpiece up a little till it has a bit of space between flame and tip then turn it back down till it touches tip. Turn oxy on gently and the flame should go blue wth a feathery flame inside it, gently add oxy till that featery flame inside it gets smaller, then press lever, a jet of oxy should be visible nearly the length of flame if it doesnt look straight tip is dirty and needs a clean. When you press lever the feathery inner flame may grow a little too. Hold lever and add oxy knob till it gets as small as it can, meaning it looks tighter etc. When cutting keep 1/4 inch roughly off steel if you hear "backfiring" lift it a bit. With acet oxy set up this can lead to flashback. Not good.
Move surely but slowly as needed. I prop one hand under and use it as a pivot to cut a foot or so at a time. Use grinder to make a straight line as chalk can burn off a little before you get to it. Turn cylinders off EVERYTIME you stop even if its just a coffee break. Trust me.
And have fun with it, grab some scrap have a practise and dont be too hard on yourself. The positive to oxy cutting is if its not hot enough it wont cut, this is good when you need to use that to you advantage. Oh dont have feet right under it slag will find the smallest hole in boots

[Chips O'Toole]

Thanks for writing all that. I may print it out and take it with me.

You are right about sparks. Yesterday, I was wearing boots that fit tightly around my ankles, and a spark hit me on the top of my foot somehow.