Not ready to quit my day job

jaybee · February 28, 2006, 10:22:28 AM

I've been practicing my gas welding and although I haven't been able to spend as much time as I'd like on it I'm already pretty good at making weak, ugly welds with no penetration. Obviously that gives me a great sense of accomplishment, but I'd like to move up to something more advanced.

For practice I've mostly been using some thin-wall rectangular tubing I had laying around, cutting slits in it and trying to weld them back up. I'm using 4psi on both the Oxygen and Acetylene. I can see the puddle but am having trouble finding that middle ground between just hot enough to keep the rod from sticking and blowing out the bottom. Any advice?

Dave · February 28, 2006, 06:13:08 PM

Quote from: "jaybee"I've been practicing my gas welding and although I haven't been able to spend as much time as I'd like on it I'm already pretty good at making weak, ugly welds with no penetration. Obviously that gives me a great sense of accomplishment, but I'd like to move up to something more advanced. For practice I've mostly been using some thin-wall rectangular tubing I had laying around, cutting slits in it and trying to weld them back up. I'm using 4psi on both the Oxygen and Acetylene. I can see the puddle but am having trouble finding that middle ground between just hot enough to keep the rod from sticking and blowing out the bottom. Any advice?

My favorite is gas welding exhaust pipe. I even have a mig but I like the gas welding better.
Dave

enjenjo · February 28, 2006, 07:37:03 PM

Basically what you do, is control the heat with the rod. You dip the heat in, when it starts to flow, stick the rod in. When it starts to cool, pull the rod out. It becomes easier with practice. What kind of torch are you using? What size tip?

jaybee · February 28, 2006, 09:25:34 PM

Quote from: "enjenjo"Basically what you do, is control the heat with the rod. You dip the heat in, when it starts to flow, stick the rod in. When it starts to cool, pull the rod out. It becomes easier with practice. What kind of torch are you using? What size tip?

Thanks, that makes sense. I've been trying to control the heat almost entirely by moving the torch in and out, and sort of stabbing with the rod. It just isn't precise enough to melt deeply into the metal but not all th way through. The torch is a no-name Chinese tool from Harbor Freight. It came with one welding tip, which the box said was a #4, but is stamped 2-W-J. I haven't measured the thickness of my practice stock but it's pretty thin (maybe as thick as muffler tubing) and it takes about a 5 count to heat it red, a little longer to puddle. I have also played with some 1/2" plate I have laying around. I can barely make a puddle on the surface and can't move without losing it. Will I need something smaller to be successful on sheet metal or will this work?

enjenjo · February 28, 2006, 09:57:54 PM

Most sheet metal, I use a number 1 tip on my Purox torch, number 2 with the Henrob. Your torch should be close to the Purox. The problem with too big a tip, the puddle is too big to control on thin metal.

GPster · February 28, 2006, 10:17:01 PM

I don't put the flame tip in-and-out , I go from side-to-side on each side of the joint (one piece to the other) and add filler metal as it will take it . The movement of the tip keeps the puddle moving and I add the rod not to the puddle but to the crevace between the two pieces before the puddle. If you're going to try gas welding 1/2" plate you might as well use your cutting torch. I can't remember exactly the rules but my rule of thumb is weld two like thicknesses of metal the crevase between the pieces should be about half the thickness of the metal and my best luck has been with thin rod. I have used bailing wire and wire clothes hangers but the rod made for the purpose always gives me the nicest joint. I usually work with the acetolyne pressure about 6 and oxygen pressure about 15. I adjust the acetolyne flame so it's at the point just before the flame leaves the end of the torch tip and then I add oxygen so the length of the flame is about 1/2" long form the end of the tip to the endof the flame. Just keep playing and feel (not literaly) what you need to do. I would stop with the 1/2" plate because there would be little use for that in the real world . GPster

jaybee · March 04, 2006, 05:53:08 PM

Thanks for your suggestions. Along with those I found things going a lot more easily if I fit my parts very closely, clean the back side of my joint better (I'm working with tubing so it was out of sight and out of mind) and be more diligent about keeping flux on the rod at all times. Now I'm making welds that LOOK like welds instead of industrial accidents and they can take a beating with a hammer without breaking.