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O/A Cutting - Results

Ok, guys thanks. I have no idea what tip I have. Its a generic HF. My O2 gage is a Smith and my Acet gage is a Gentec that a friend gave me after my after my smith A gage decided to take a dump and spill Acet everywhere. Anyway, its frankenstein. My Smith head was t*ts up and cost more to rebuild (according to the local welding shop) than I wanted to spend. Anyway, I finally got out back today to cut some more steel off the giving tree for another project.

(More on the giving tree later)

I followed your advice. Tip drilled all the tip ports. Dressed the face of the cutting tip with a file, and then set the regulators first with pressure and then with flow. Big difference, but I knew that. O2 reads 35 closed for 25 flowing, and the Acet reads 8 closed vs 4 flowing. With gas flowing I set them at 4 and 25 and went to work. I was cutting various sizes of c-channel from 2" and about 1/8 thick to 4" at nearly 3/8 in the corners. At those settings if I took my time I got a pretty darn cut on all of it my lack of skill not with standing. I got less than 1/8" of kerf on all of it including the thickest sections, and when I was cutting properly I got no slag at all on the top side, and very little on the bottom.

I noticed a couple things. First is it gets all slag crazy if you have to cut into an inside corner. Probably because the effective thickness approaches 3/4" at that angle. The other was that if you go a little to fast and loose the cut its harder to restart than it is at an edge for some reason. Maybe because there is more metal to heat up. I found if I used a gas welding technique and made little circles with my cutting head to heat up the metal around the cut it would restart again easier.

Thanks guys. All the tips helped me make hack through the metal a lot easier. I did find it was a lot harder for me to keep the cutting head going straight than I remembered, but then in the past I was creating so much slag I probably just could not tell.

For those who made it this far the giving tree is an old boat trailer a guy gave me. He told me to use it if I could, and if not sell it or whatever. A buddy short on cash needed some wheels because the fancy mags on his boat trailer were cracking. He got the white steel spoke rims that were on it. Another buddy stripped the winch on his trailer. A while back I needed to unload some farm implements, so I cut up the front A frame portion of the trailer and made some slip on forks for my front loader out of part of the

4" c-channel main frame. Today I cut out several sections to make a front hitch and slide in mount for a Warn winch to go on my 4x4 truck (or where ever I need it). This junk trailer that a guy I didn't even know gave to me (with the title) just keeps giving and giving... Heck. I still have the hitch, jack, and two good axles along with the fenders and some steel diamond plate, and even some of the frame left.

The guy offered me the trailer for free because he thought I could use it, and he would have to do a lot of work he didn't want to do to make into something he could give to his brother in law for his yard service business. After he had already given me the trailer I learned the other part. I had a small tilt bed trailer I hardly use that has nice stake sides. (I have two other flatbeds for hauling stuff besides) It was perfect for his brother inlaw's yard service business, so when I went to pick up the trailer I took mine with me. Didn't even tell the guy. He was floored. We both got a lot of use out our "trade" and this big boat trailer I got is still finding new uses nearly a year later. His brother inlaw got a great Christmas present. I'm gonna be sad when all that steel is gone though and I have to go buy some for the next project afterwards. Heck today alone I got about $200 in steel off of it if I had to go to the steel yard and buy it for this project.

Bob La Londe

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Reply to
Bob La Londe
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When cutting angle or channel, wherever positionally possible, I like to heat the peak, and make one cut through the thick stuff, twisting the torch to cut one leg, then coming back and cutting the other leg, or the other point and leg as with channel. I never had good luck cutting from the inside, or it stutter stepped and made a messy looking cut. Particularly if the web is thicker, as some channel and angle is.

Steve

Reply to
SteveB

Sorry, brain fart and deleted info in last post. Good to hear you are doing well and progressing. A couple of things .......... watch that acet pressure, as that is dangerous. If you don't have a gauge that will give you an accurate measurement, either have that one fixed, or get another. You can fudge on the O2, and mostly judge by the performance, but acet notifies you by a large fireball and a big noise.

As for the boat trailer, NEVER EVER toss stuff, as you will need exactly that in less than a week.

For OA cuts on thin stuff, heat it up until you get a red spot, then turn the torch to like 10 degrees with the flame pointed into the metal, and you can even let the edge of the torch sit on the metal, and blow you a line two inches long in front of the tip. If you can't grasp this, let me know, and I'll post a pic. Talk about cutting thin and it looking like a saw cut ............. this will do it.

Yer doin good. First thing is to get the torch working, the settings right, then just cut "stuff".

I would suggest one more thing. Take some Windex and check your connections. ALMOST nothing as exciting as looking back and seeing your hose burning back to the tanks like a Wiley E. Coyote episode.

Steve

Reply to
SteveB

Not sure why you think its not accurate? Nor specifically what you think is dangerous about it. Some of the guys here suggested 4/25 when cutting and that's what I ran with with good success.

Reply to
Bob La Londe

If you notice on an acet regulator, there is a red zone that starts around

7psi. You said yours was running 8. I've used regulators where none of the gauges were working, and they didn't blow up and I'm still here. And then there's the ones you read about in the papers.

Ernie, what say ye?

Steve

Reply to
SteveB

** Then according to this Victor chart Grant posted wouldn't anybody cutting heavier materials be at risk just by following the published chart?

Victor Acetylene Cutting Tip Chart

- Cutting Tip Series 1-101, 3-101, 5-101

METAL TIP OXYGEN FUEL SPEED KERF THICK. SIZE PSIG PSIG I.P.M. WIDTH 1/8 000 20-25 3-5 28-30 .04" 1/4 00 20-25 3-5 27-30 .05" 3/8 0 25-30 3-5 24-28 .06" 1/2 0 30-35 3-5 20-24 .06" 3/4 1 30-35 3-5 17-21 .07" 1 2 35-40 3-6 15-19 .09"

** 2 3 40-45 4-8 12-15 .11" ** 3 4 40-50 5-10 9-12 .12" ** 4 5 45-55 5-10 8-11 .15"

Also found here:

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Did you maybe think my high pressure side was at 8 psi?

Reply to
Bob La Londe

Steve's brain fart seems to be continuing. Acetylene does have a danger zone but it starts at 15psi not at 8, as practically any of us could have seen by going and looking at their gauges.

Grant

Reply to
Grant

And it seems so is mine... LOL... I just cut out some notches (making a front hitch for my truck to mount a winch), and my Acet regulator is only fluctuating about 1-2 pounds from flow to off. Weird. Maybe I should look at replacing it. 4 flow & 5.5 off. I have not done any adjusting since yesterday. Just turned the tank off last night and back on this morning.

Reply to
Bob La Londe

The Red zone starts at 15 PSI on all fuel gas regulators.

15 - 30 PSI is the danger zone for acetylene.

At 30 PSI acetylene can Deflagrate, which basically means decay while generating massive amounts of heat, or "blow up". It doesn't need oxygen or a spark to do this, just pressure.

Reply to
Ernie Leimkuhler

But, but, but ...

Isn't it at around 300 PSI in the tank? How come _they_ don't explode?

Reply to
Tim Wescott

Acet regs go up to 15, IIRC. I have always kept mine at 8 tops, but then never really cut anything thicker than one inch. It's the O2 that does the cutting anyway.

Steve

Reply to
SteveB

Sorry, Grant. Was relying on memory and experience. I was wrong. That makes twice now.

Steve ;-)

Reply to
SteveB

It's not in a gaseous state in the cylinder, well at least for a small volume at the top, it's dissolved in acetone in a porous substrate.

Reply to
Pete C.

15 psi is the start of the danger zone for _moving_ acetylene. It can be higher if it is not moving. E.g. rosebuds sometimes require 15 psi acetylene to work properly. That makes it go significantly over 15 psi when the torch valve is closed. Smith even put a special note in their manuals explicitely stating that acetylene pressure can go over 15 psi when the torch is shut off but this is normal and acceptable.
Reply to
Sergey Kubushin

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