help with acetylene torch

[crosby]

I am trying to learn how to use a torch, and seem to have a problem with mine. I read my Welder's book, which gives pretty explicit directions. They have me using 1 to 2 lbs of actylene, and 10 to 12 lbs of oxygen. I am cutting the straps off the driveshaft of my one ton, and all was going well until all of a sudden, it stopped being blue, and turned yellow, and started popping. Like I was out of oxygen or something... I shut everything off, started again (lit the torch) and as soon as I added oxygen, it shut itself off (the flame went out). Twice I tried to start it again and it popped and shut itself off when I added oxgen on the torch tip oxygen valve. Both the oxygen and acetylene have over 100lbs in each bottle. What could be happening? The torch is pretty old, I bought it for $75 with both tanks out of the Want Ad, a local buy/sell/swap book you can buy at gas stations and the supermarket. Now I am afraid something is wrong and it will blow up in my face. Thanks for any help you guys can provide!!

[Phuloi68]

There are several things there. What size tanks? 100 lbs oxy is not very much. What size tip? 1-2 lbs act, even with a small tip, is not much.
If your using a small tip (2, 4, 6) use about 5-7 lbs act. and 40 or 50 lbs oxy.
Crack open the act, use striker to ignite, then slowly add oxy. Sometimes holding torch at angle having flame on metal then adding oxy helps.
old torch may have worn valve seats, packing.
make sure you have check valves on torch. keeps flashback from going in hose.

[crosby]

Thanks for the info Phuloi. I was just looking at the guages, and noticed the oxygen is 1000, not 100 lbs (tank pressure). Even still, that is low on the guage (but not near empty). I think the tip is a 0, does that make sense? When I bought it, I said I wanted to cut 1/4 inch steel (for no apparent reason). My welding book said 1-2 lbs of acetylene and 10-12 of oxygen, do you think that's wrong, or does it depend on the thickness of the metal? Does the popping seem to indicate a lack of oxygen? How can I check to see if I have check valves? Sorry for all of the questions, I don't know a lot about torches and cutting. It's lots of fun though when it does work! I cut through one of the driveshaft straps, but just not enough in the right place to free the driveshaft. GRRR!!! Now I think I am out of oxygen or something. Thank you again for all of your help.

[79C10]

sounds like you hit the oxy. valve will cutting then turned the oxy. on to fast the next two times but sounds like your settings may be low like Phuloi68 said i would also try cleaning the torch tip it may be clogged

[crosby]

good point, I will try cleaning the tip next. I just barely hit the oxy when I started the flame...

[Ltd4wheel]

There should be two valves for the O-2. One is set for the force of the cut and the one next to the acc is to set the flame. If it goes out when you hit the O-2 cut valve turn down valve next to where the tip connects to the handle. 7 to 40 should be about right. Louis

[us111]

hello,,,cuttin torches,,espicially older ones can be a pain,,you try to light you get a bang (pop),,you get them lite you get black stuff that will choke ya,,, there like anything else,,just play with them,,do not turn on oxy to quick after lighting,,,and like they said,,if tip is junk or plugged you will never get it to work,,,also when you do get going if you get to close to work you will get a big pop,torch out,,,etc.... hope that helps a little...

[Phuloi68]

As stated, a clean tip is important. I would set the act. at 4-6 lbs and the oxy at about 30 with a 0 tip (it is a cutting tip and not a welding tip?). You will have a flame within a flame. When you light it it will be yellowish and as you add oxy a blueish small cone shaped flame will be just past the end of the tip. Adjust till it is at its sharpest point and your ready. As you learn you might vary your mixtures a little depending on what you are cutting.
When you cut the angle of the torch helps too. You don't want the slag filling in behind you. Get a piece of scrap metal and practice cutting. The tip is supposed to be just a little away from the metal. That little blue cone in flame is your hottest point. if you get tip to close you will get popping, etc.
Check valves are between hose and torch. about 1-1/4" long. male/female threads. one left threaded and one right threaded.
Also, on knobs that you adjust your fuel mixtures, there is nut at stems. You may want to gently snug down on them. not to much cause your adjustment knobs will be hard to turn.
Finally, make sure when cutting, your feet are not under what you are cutting cause some of those red hot blobs fall in your shoe, they burn like H**L. (learned that the hard way)

[crosby]

Thanks guys, it all sounds like good info. It's when I add oxygen at the tip that it cuts out. My book says to turn the oxygen full blast at the base, and slowly add it at the tip (mixture). Does that make sense? The tip is new, but the torch is older than dirt. When you hit the oxygen handle, it sticks and sometimes doesn't bounce back unless you push it back (off). It was working great for a few minutes there... I will try playing around with it in the morning. Got to get something done before the kids come home tomorrow night! Take care everyone, thanks again.