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So, I've been practicing oxy-acetylene welding over the last couple of weeks. I had done it a little bit before in a welding class about 15 years ago. After I got to the point where I could reliably join two pieces of metal together with a weld that looked somewhat ok, I started wondering how the welds would hold up. So, I devised a way to do some destruct testing using a common engine hoist (aka cherry picker).
I'm welding with a Smith medium duty torch. I'm using MW201 and MW203 tips. I already had the torch so I just had to buy the tips. I've probably got about $350 in my gas welding setup. I'd like to have a TIG welder, but I just can't see spending the money. I'm using 1/16" and 3/32" RG-45 welding rods.
My hoist has an 8 ton jack on it so it is more than sufficient to tear up some thin wall 4130 tubing. My test coupons were made of .035" wall, 3/4" diameter, 4130 tubing welded in an "I" shape.
To attach this to the engine hoist, I just needed some 1/2" bolts and qty 4 simple metal brackets with 2 holes each, at about a 2.5" hole spread. I was going to make these brackets, but I found some that would do what I needed in the scrap bin at work. They've got some extra holes, but they'll get the job done.
After everything is in place, its just a matter of extending the hydraulic jack until the coupon breaks. I did make sure that there was a barrier between me and the test coupon to keep any debri from hitting me, safety first!. When the part breaks, it isn't too violent, but you definitely know when it happens.
As you can see, my first test piece broke at the weld. I had shown this part to our top welder at work before the test. He noted some undercutting in my weld. After it broke, I noticed that there were some spots where I didn't have good penetration either. Good information to have.
With this information, we decided that I needed more heat and more filler. So, I stepped up 1 size tip and I ended up making two passes over both welds in the coupon. If I slow my weld down, I think I can accomplish this in 1 pass. I'm also experimenting with larger diamer (3/32") welding rods. Its useful to be able to try different things to see what works and what doesn't
Here is the result. The weld is still sloppy, but the fillet is bigger and there is much less undercutting.
And now for a test.
Those are 1/2" grade 8 bolts bending under the load. I didn't see that last time. Its taking alot more effort to break the part this time too.
And here you see where it failed. The tube simply pulled apart, the weld did not break or crack.
Now, this is obviously not very scientific, but its still a good way for me to see better feedback as to how good or bad my welds are and to help me see what works and what doesn't. I don't think this can give me any indication as to how my welds will hold up against fatigue either. But, its better than nothing. I'm still a long way from being a welder, but I'm making progress.
I'm welding with a Smith medium duty torch. I'm using MW201 and MW203 tips. I already had the torch so I just had to buy the tips. I've probably got about $350 in my gas welding setup. I'd like to have a TIG welder, but I just can't see spending the money. I'm using 1/16" and 3/32" RG-45 welding rods.
My hoist has an 8 ton jack on it so it is more than sufficient to tear up some thin wall 4130 tubing. My test coupons were made of .035" wall, 3/4" diameter, 4130 tubing welded in an "I" shape.
To attach this to the engine hoist, I just needed some 1/2" bolts and qty 4 simple metal brackets with 2 holes each, at about a 2.5" hole spread. I was going to make these brackets, but I found some that would do what I needed in the scrap bin at work. They've got some extra holes, but they'll get the job done.
After everything is in place, its just a matter of extending the hydraulic jack until the coupon breaks. I did make sure that there was a barrier between me and the test coupon to keep any debri from hitting me, safety first!. When the part breaks, it isn't too violent, but you definitely know when it happens.
As you can see, my first test piece broke at the weld. I had shown this part to our top welder at work before the test. He noted some undercutting in my weld. After it broke, I noticed that there were some spots where I didn't have good penetration either. Good information to have.
With this information, we decided that I needed more heat and more filler. So, I stepped up 1 size tip and I ended up making two passes over both welds in the coupon. If I slow my weld down, I think I can accomplish this in 1 pass. I'm also experimenting with larger diamer (3/32") welding rods. Its useful to be able to try different things to see what works and what doesn't
Here is the result. The weld is still sloppy, but the fillet is bigger and there is much less undercutting.
And now for a test.
Those are 1/2" grade 8 bolts bending under the load. I didn't see that last time. Its taking alot more effort to break the part this time too.
And here you see where it failed. The tube simply pulled apart, the weld did not break or crack.
Now, this is obviously not very scientific, but its still a good way for me to see better feedback as to how good or bad my welds are and to help me see what works and what doesn't. I don't think this can give me any indication as to how my welds will hold up against fatigue either. But, its better than nothing. I'm still a long way from being a welder, but I'm making progress.
