7018 Welding Rods for the Hobbyist
Although mostly used for structural fabrication and erection, many home hobbyist are discovering the great benefits of 7018 electrodes. Most shop and field jobs receive 7018 electrodes in 50 pound boxes. Because of the need to store these rods properly, it is often suggested to the hobbyist that they should purchase anywhere from 1 pound to 10 pound packets. This is not good for two reasons:
First, buying anything under 50 pounds increases the price BIG TIME!!! It is highway robbery buying small packets at many of the building supply stores and even at many welding supply stores. I don't know if it's because it's more of a pain putting the electrodes (rods) in the packages or what, but you are WAY better off buying the 50 pound containers unless you plan on only using a very small amount.
I'm not sure why small amounts cost so much more, maybe it is because of packaging. I took a tour of Hobart's electrode production plant while visiting Hobart's Welding School in Troy, Ohio a few years back. It was really interesting watching how the rods were made. What surprised me most, or I should say, what freaked me out the most, was seeing how they were packaged! Here is this elaborate plant with all kinds of computers, conveyors, extractors, etc. and then at the very end of the process is…some guy putting them in the cans.
I'm expecting some big piece of machinery placing all these 7018 rods on different belts to be fed precisely into each can. What I'm seeing is this guy grabbing handfuls of rods and madly filling up each can! You talk about a job where you better be in good shape, and don't EVEN come in with a hangover!
I guess it's hard enough putting handfuls of 7018 into 50 pound cans, and even more labor intensive to put them in one, two, five, or ten pound packets. I didn't get a chance to see how that was done.
I've seen 5 pounds of 7018 rods costing FOUR TIMES more at one of the big hardware/building stores than what it would cost if you were to buy in the larger 50 pound quantity at the welding supply store. These prices are changing almost daily, and when I say changing, I mean going up! Prices I've paid for steel and rods have doubled and tripled over the last couple of years.
The second and even more important reason it's better to buy 7018 in the 50 pound boxes is because they are hermetically sealed to keep moisture out.
If you're old enough to remember watching Johnny Carson on The Tonight Show, you remember him as Carmac the magician with his "hermetically sealed envelopes." They were sealed so he would not know the question inside. He would give a funny answer, then open the envelope and read a question, usually getting a lot of laughs. The neat thing about Johnny was, even if the joke wasn't funny, his look into the camera always was.
I said it is important to receive the rods*** sealed in their packets. The reason for this is 7018 is a low hydrogen rod. It does not tolerate moisture and must be kept dry before use. If not, when welding it will allow for pitting and porosity (worm holes) which are weld defects. This happens when moisture gets in the flux coating and allows hydrogen to adversely affect the weld pool. I'll discuss other defects in more detail in a different article.
7018 rods that haven't been dried properly may make a good looking weld at first that will be subject to longitudinal cracking either right after welding, or later on. Longitudinal cracking is where a crack starts and follows the length of the weld.
Whether you're using 7018 or one of the other rods or processes, you always want to make sure your weld is sound and that it looks good. The late Duane McLaughlin used to tell everyone he met that "You're weld is you're signature!" You always want to put down your best weld no matter what it is you're working on. That means it should be tied into, or fused into the steel properly, and it should have a good visual appearance.
To do that, you have to be using the right tools, equipment, and rods. More and more home hobbyists are finding out how good and versatile 7018 rods are. Heck, as a structural welder in the Iron Worker's union, I used 7018 rods to weld shopping centers, factories, high-rise office towers, power houses, dams, damn powerhouses (that's a joke) and virtually every kind of structure out there. They are fantastic for mild steel and structural construction steel.
Look at the many building projects listed at https://www.texasironandmetal.com/american-steel-structured-architecture-wonders/ and I'll bet you most were welded mainly with 7018 electrodes. Some of them may have used flux core on column splices (where one column is stacked on another at the splice that is bolted and welded solid) but I'd bet a pretty penny that most of the other welding was with 7018. Of course some of the older buildings used rivets but most of the modern structures use 7018 rods.
If 7018 rods are good enough for a high-rise office tower, they're dang sure good enough for most all of your hobby projects. Now I'm talking about relatively thick steel, and 7018 rods are not good for welding open butt or grooves** or thin sheet.
***the correct technical name for rods are "electrodes". But you will quickly find out I write on the non-technical style of the road! In the shop or field they are called rods.***
**Open butt is two pieces of plate with a space between them. Closed butt is the factory edge butted up against the other factory edge. Grooves are plates that have been beveled to an angle with a torch or grinder. This allows deep penetration of the weld.) A good illustration can be found at http://www.unified-eng.com/scitech/weld/groove.html **