Torch cutting

[Captain B]

I am a newbie and really learning from this site. I tried to cut a one inch square solid mild steel bar with my torch over the weekend. I made a small cut and then the torch "blew out" repeatedly. My settings were 7 psi acty and 25 psi oxy. Don't know the size of my cutting torch in standard terms. It's esssentially the same as the kit advertised at Northern Tool for around $160. Any suggestions?

[Hobart Expert Rock]

CAPTAIN B.............WELCOME ABOARD..........NO PUN INTENDED.... WHICH CUTTING TIP DO YOU HAVE.............THEY ARE MARKED ON THE END................ DO YOU HAVE A BRAND NAME FOR THE TORCH.........WE CAN GET MORE EXPLICIT IF WE KNOW FOR SURE WHAT WE HAVE................HOW DID YOU FIND THIS SITE...........?... WE ALWAYS LIKE TO KNOW..............ENJOY THE SITE........ROCK..
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[Captain B]

Torch cutting

Rock--Unfortunately, I bought a non-standard set at a "great price." Already learned my lesson--didn't happen again when I bought my stick machine. Doesn't have sizing indicated. I know this is imprecise but many websites seem to carry this torch kit. Looks to be enty level. Learned about your site through TractorPoint.com and I have already used info from here to bring up my skills. Also have a Hobart Stickmate AC/DC with which I am really pleased. Mainly doing tractor implement repair on thicker material (1/2") and related weekend projects such as brush guards, reinforcing my brushhog for attacking poplar--fun stuff. Thanks for any guidance.

[slowrev]

The cutting tip should have the type/size up close to the base of it. You will have to remove it from the torch to view the writing.
something like 0-3-101.

[Snidley]

Captain B..

Welcome to the group. I'm going to guess that as a sale torch, the tip will probably be a 0 or 00. This size tip is normally good for 1/4" to 3/8" thick material. It can be used on thicker, it will just take a little more care and time. Your oxy psi is fine and you have more then enough acty psi.

There should be a booklet with your torch on how to adjust your flame. To me it sounds like you may have an oxygen rich mixture. Even added to more once you add the cutting oxygen flow, this can/will lead to popping out (not enough preheat). The other may be that you are moving to fast on this thicker material. If the cut is not completely through or if the torch head is angled slightly ahead of the cut, the flame gas will kick back and can blow itself out.

For safety, make sure that your torch has an flashback arrestor.

Let us know how you make out.

[Captain B]

Torch cutting

Wow, this is a fine site--and great service to boot. I did buy the flash arrestors early on. Also, had the torch head tilted backward about 25 degrees thinking I might avoid having molten materials blow back on the torch. Almost forgot, did get a pamphlet. It's in my bookcase. Will check it and the torch head for sizing tonight and post back the info.

[Mike Sherman]

There is another possibility, you may be using more acet. than your tank can produce. A tip or torch that is too large for your bottle will go out with a load pop after being lit for a few seconds or a minute. I like to see the oxygen up around 40 psi also. Technique can have alot to do with it also, if your tip is too close to the work piece it will often go out.

[Arc Burn]

In general,i usually run 35# oxygen and 8# of acetylene.

[Captain B]

Torch cutting

I checked the torch last night. It has the following near the screw-in base of the copper cutting tip: "6290 - 1#" Does that indicate size? If so, is it adequate for 1" square bars? I have a 40 cu. ft. acty tank. The three welding tips I got with the set don't seem to have any sizing info on the copper tips that screw into the cutting handle. By the way, I learned to my chagrin that the set may be metric. When the cutting flame blew out there was no pop--just went out silently and suddenly. Any futher ideas?

[Franz]

A 40 cf acetelene tank can support a cutting torch, I do it regularly with B Prestolite tanks cause I'm old and too lazy to carry the big tanks up stairs.
One question would be, has your tank still got sufficient gas in it to support the torch, or is the tank empty? If your regulators don't have 2 gagues on them, watch the delivered gas gague to see if it is dropping off as the torch burns,
A second question is how long are your hoses, and what diameter hose do you have?
I have no reference to Northern Tool because I long ago decided outfits such as Northenr and Harbour Freight exist only to make you wish you'd bought a real tool.

[ChadRat]

If it was me then I would set the oxy to 30 and the acet to 6. I would preheat the edge to a nice glow red and push the lever and go slow.