Friday, October 07, 2005
So last night I had another welding class... We had a demonstraion on MIG welding. To be honest it kind of bored me. The weld is nearly perfect without any effort. MIG isn't the term that they use anymore I guess. What we did was GMAW (gas metal arc welding). Basically there's a little bit of gas that shields the metal and wire from the outside air and a wire that is being constantly fed. Here's a pic that I stole from another site. It shows the gun(or whatever it's called) and the ground clamp.
I tried a couple of times and went back to my paddle.
So basically for the past several classes, except for the first two where we did oxy/acetelyne welding, we have been doing stick welding... according to Lincoln Electric
A short stick of welding filler metal consisting of a core of bare electrode covered by chemical or metallic materials that provide shielding of the welding arc against the surrounding air. It also completes the electrical current, thereby creating the arc. (Also known as SMAW, or Stick Metal Arc Welding.)
Basically we've been sitting in our little booths (I'm in booth 13) stick welding. We were supposed to start with 6013 wire last night, but perhaps the instructor forgot...
Here are some pictures I took last night at class. I wanted to get some of the shop, but because it was open house for the high schoolers, I didn't think it would have been appropriate. So, I just have pictures of what I'm working on at present.
Ok in this photo you can see my paddle that I'm basically just filling up with weld bead, my slag pick for hammering off the slag (I'll get to what that is in a minute), my wire brush for cleaning off the rest of the slag that the slag pick doesn't pick off and the stinger which holds the "stick"
Here's a decent picture of the sticks used for this process. They are covered with flux which is the gray matter.
And yes I have to wear a mask.
Ok in this picture you can see what a fresh weld looks like. Basically it's all covered in slag...
- A layer of flux soot the protects the weld from oxides and other contaminants while the weld is solidifying (cooling). Slag is to be removed after cooling.
The amount of slag produced varies according to what type of rod is used or what kind of process is used. We started out using 6010 wire. According to our instructor, that is the hardest type of rod to start out with because it's harder to control. It's also a pain in the ass because the slag is harder to remove and it spatters like crazy.
- Metal particles thrown from the weld, often cooling and hardening on the work surface. A spatter-resistant spray applied to the workpiece can minimize spatter.
I want spatter resistant spray!
In this pic I've hit the weld bead with the slag pick a few times to remove the slag. Not all of it though, only so I could show what it looks like. I can't wait to start working with other rods, I'm not seeing all that much difference in the 6010 and the 6011 wire... Only that I can hold the rod proactically inches away from the base metal when using 6010... That's not really recommended, but I tried it just so I could see if the instructor was pulling our legs...
Underneath all of that black slag is a shiney weld bead. I really wish I could have managed to get some closer shots, but that's as good as I could get with that camera. After you pick off the slag with the slag pick, you still haven't gotten all of it off, so it's necessary to use the wire brush. If your base metal isn't clean, sometimes you can't establish an arc or even worse you could damage the weld with porosity.
Arc [Arc Length] - The physical gap between the end of the electrode to the point where the arc makes contact with the base metal.
Electrode - A coated metal wire having the same composition as the material being welded.
Porosity - Porosity is the result of gas being entrapped in solidifying weld metal.
As you can see with these two pics I'm still trying to master the straight line. The 6010 wire was a mess. Spatter went everywhere and one night when I was wearing a pair of jeans that were frayed on the bottom, I caught my pants on fire. I'm still getting some spatter with the 6011, but definately not as bad.
In this pic you can see my progression with the 6011 wire. Last night definately wasn't my best night welding and unfortunately my better beads are underneath the fresh ones. I was having an off night I think. My weld beads were starting fat and going crooked. In the last 15 minutes of class I had maybe one perfect weldbead. Not too fat with good penetration.
unfortunately this isn't a good picture... oh well...
I am your friendly neighborhood welder. May I melt your metal?