Despite what the title of this post may sound like, the building did not go down in flames shortly after beginning my adventures in welding. The title comes from my surprise of finding out we wouldn't be starting with welding two pieces of metal together, but rather cutting a piece of metal in half using a torch that sounded like a jet engine and spit long blue flames!
Here's where I will be doing the majority of my learning and practice for the rest of the semester. This is a small area of the large technology lab where I teach middle school students about how things work, and how to make them. Of all the subjects I teach, I would consider metal working my weakest point, so I look forward to bolstering my skills while learning from my dad, someone who I consider to be a true professional.
The main reason we focused on using a torch before learning to weld was the fact that most of the time you have to prepare your materials by cutting them to size before any welding can be done. While there are other torches available that would do a better job of cutting metal plate, such as a plasma cutter, my shop is equipped with one of the most commonly used setups. It consists of a handheld torch with two lines that run to a tank of oxygen, and a fuel called acetylene. There are nozzles that adjust the amount that comes from each tank, and the trick is getting the mixture just right. I was told you should get a flame about one foot or longer, and a sound that is similar to a jet flying overhead. I would later find out this is easier said than done. |
I was mistaken in my assumption that a torch cut through metal through shear force, with the extreme hear piercing a hole straight through it. This is where I noticed somewhat of an expert blind spot from my dad. I could recall that he quickly mentioned, almost in passing, the fact that I should allow the torch to preheat the very edge of the piece of metal before moving it to make the cut. I assumed he just meant to make the metal warm, and he assumed that I understood the real reason why it needed to be preheated. It started to make sense when I moved the torch to the center of the piece of metal and nothing happened. He then reminded me to preheat the metal, and I was able to make a cut like the picture to the right. As it turns out, the way a torch cuts through metal is similar to the way water erodes away at a hillside. It doesn't pierce a hole straight through the center, it carves a path by pushing material down the side, clearing away space to continue removing even more material. In the case of the eroding hillside, the material that is flowing away would be called mud. When we're talking about cutting metal, the material being removed is referred to as slag. |
The equipment we were using for this learning experience hadn't been very well maintained, having last been used be middle school students and all, so the nozzle on the torch was very dirty. This inhibits the flame from cutting the way it's supposed to, causing ugly slag spatter like the image to the upper right. Once the nozzle was clean, however, I was able to make much nicer cuts.
Now that I know a bit more about how to get metal ready to be welded, I'm excited to see what's in store. This has already taught me so much and taken away a lot of the confusion I had in the past about welding and metalwork in general. Well, join me next week in my attempt to stick two pieces of metal together without going blind!
As we were welding, my dad said something that caused me to think of what we learned in class while discussing our cognitive architectures, particularly the concept of automaticity. While discussing the need to practice in order to be able to lay down an acceptable weld, he mentioned that the last time he used that particular type of stick welder was probably over 20 years ago, and yet his demonstration was perfect. The hand eye coordination stored in his long term memory had been so well developed in the past, that once the familiar feel of a welding rod was in his hand he didn't even have to think about it. I, on the other hand, was working entirely from working memory, trying to do multiple things at once. I had to consciously think about hold the rod at the right angle, sweeping it in a "c" shaped motion, moving it closer to the metal as the rod itself wore away, etc., all without the benefit of having any of that information chunked together. Looking at it this way just further proves the point that I need to keep practicing!
As we were welding, my dad said something that caused me to think of what we learned in class while discussing our cognitive architectures, particularly the concept of automaticity. While discussing the need to practice in order to be able to lay down an acceptable weld, he mentioned that the last time he used that particular type of stick welder was probably over 20 years ago, and yet his demonstration was perfect. The hand eye coordination stored in his long term memory had been so well developed in the past, that once the familiar feel of a welding rod was in his hand he didn't even have to think about it. I, on the other hand, was working entirely from working memory, trying to do multiple things at once. I had to consciously think about hold the rod at the right angle, sweeping it in a "c" shaped motion, moving it closer to the metal as the rod itself wore away, etc., all without the benefit of having any of that information chunked together. Looking at it this way just further proves the point that I need to keep practicing!