After reading the past two Fab 101 articles, it’s finally time to come up with a design. However, there are a few things to consider before you flip on the welder, and start laying down some beads. If you’re building a bumper, how long is it going to be? Are you going to have to remove the stock bumper? Is it going to be a bolt-on bumper, or a weld-on bumper? When dealing with a full build (pictured here), there are numerous things to take into account like weight distribution, wheel size, drivetrain, and many more.
Author: Jordan Powell Photos: Jordan Powell
Fabrication is an expression of human creativity. It’s art. With an imagination, a blank canvas and some fabricating tools, you can transform any idea into your own Masterpiece In Metal, whether that’s a front bumper for a Ford Ranger, or an exotic tube chassis for a Trophy-Truck. Before you can start bending and notching some tubes, though, you need to have a general idea of your design, because there are many key components you need to consider before jumping into the deep end. At the Fab School in Riverside, California, owner Troy Johnson knows that many of his first-time students would rather grab a welder and have at it than listen to the countless “Introduction to Fabrication” tips. But the fact of the matter is, you need to know the basics to become a successful fabricator. We know, it sucks, but like the old saying goes, “You have to walk before you can run.” By having a solid understanding of the basics, you’ll be able to think two steps ahead of your work, which will save you from headaches later on down the road. In the previous two issues, we got you up to date with the necessary gear needed to become a skilled fabricator, along with some basic tips. Now it’s time to get down to business. That’s right, it’s time to come up with the design, and how to mock it up. So, to help us with this process, we enlisted the help of the head professor at the Fab School, Mr. Johnson.
“Know Your Knowns”:
Unless you’re starting from the ground up, your project will most likely not have a lot of unknowns. For instance, this Ford Raptor might get a few new upgrades in the cab, but other than that, there isn’t a lot of need to mock anything up. So, it’s readily available to start laying out some tubes for a rollcage.
“KNOW YOUR KNOWNS” One key phrase Troy likes to teach his students is “Know your knowns.” Now, you’re probably asking yourself right now, “Is knowns even a word?” Although we’re pretty sure it’s not, the idea is simple; before jumping into a project, you have to ask yourself, “What parts are going to be used for this?” If you’re starting a project from the ground up, there are going to be plenty of unknowns that need to be checked off before you can proceed. On the other side of the spectrum, if you already have a truck that you just want to mount a bumper on, there aren’t that many unknowns you have to worry about. If racing out in the desert is one of your ultimate goals, Troy mentioned that one crucial element to know when doing a full build is the wheels. “When you start on a project, you might go in thinking you want to use a trick wheel, but realistically, you should run what everyone else is running. That way, if you managed to destroy a wheel, you can borrow one from someone else.” Once that is taken care of, you can start filling in the rest of the unknowns. However, if you don’t have your hands on all of the parts you need, it’s not the end of the world. “You don’t have to have a junk battery laying around when fabricating up a tray,” said Johnson. “With the high-tech cell phones these days, you can go online, figure out the dimensions for the battery, and simply build a mockup of it with some cardboard. After you’ve finished constructing your piece, you can tape it wherever it needs to go. All you’re doing is creating an illusion.” TRYING TO FIND A BALANCE One thing you also need to consider before starting a full build is weight distribution. “We like to keep the weight spread out as evenly as possible,” explained Troy. “I stress the importance of this a lot with my students, because the last thing you want is an unbalanced car. So, one of the things we do to manage weight distribution is throw the fuel down the center of the car. By doing so, only the ride height comes up as you lose fuel. If you have the fuel tank at the back of the truck, the rear end will squat under a full tank, and then it will be way up in the air when it is empty.”
When fabricating, you might not always have the parts you need. That’s when you either have to cut out some chipboard or cardboard to help you visualize the end result. Troy Johnson explained that your cutout doesn’t need to be perfect. All it’s doing is serving as a loose model for the final product.
TO BE A GOOD FABRICATOR, YOU MUST FIRST BE A GOOD MECHANIC The ability to visualize, and think ahead when you start fabricating can save you tons of time down the road. For instance, there will be a time when a bumper or trailing arm will need to come off, and you might notice that you don’t have enough clearance to beat a bolt out, because let’s be honest, a bolt never comes out without a little persuasion. If you didn’t take that problem into account before you started fabricating, you most likely will be cutting apart your work to gain access. Other components you need to consider on a build (if you are building a full chassis) are the exhaust and the wiring. When laying out an exhaust, you want to be conscious of where your electrical and plumbing components are going to fall into place because the last thing you need are some melted wires and an overheating problem. Having the mechanical know-how of how parts come off, what access is needed to get to them and what parts shouldn’t be near others is vital. A racecar designed strictly by engineers can be a thing of extreme mechanical beauty, but is often a nightmare for teams to work on. Often this is because the enginerds gave little thought to what the mechanics have to go through. Even something as simple as an exhaust mount requires some mechanical sense. Without the knowledge that an exhaust is constantly vibrating and often requires some kind of isolation mount (rubber bushings, etc.), one might just build a solid mount that will more than likely crack fairly quickly. For building fairly simple parts, one can get away with little mechanical knowledge, but after that you are going to need some. After all, if you can’t understand the dynamics and the needs of the part you are building, then how can you hope to build it properly?
After everything is mocked up, it’s finally time to start laying out your design. Since you’ll be in the early development stages of your project, it’s important only to tack-weld pieces together. When doing so, you should always tack-weld areas that will be easily accessible with a grinding wheel because, as you figure it out, your project might change as you put more time into it. TACK AWAY Finally, the end is near. The main goal behind all of this is to know what you’re doing, before you do it. Like any master of the arts, you have to be able to visualize your project before you actually start it. You’ll save yourself from a lot of frustration by doing so. With that said, you can finally start laying out some sheet metal and tubes, and start the build process. When building, only tack weld in an area that can be easily accessed with a cut-off wheel, and don’t be in such a hurry to weld. We know that may be asking a lot, but like Troy says, “Your idea may change for the better as your project evolves.” Perhaps the biggest takeaway from this installment of Fab 101 is that while most of us of are eager to fire up our welders and start zapping together anything we can, taking time to understand the fundamentals of design before even cutting a tube is vital. There is a huge difference between being a welder and a proper fabricator. One simply melds metal into metal while a fabricator builds anything from a battery box to a full-blown Trophy-Truck. If you want to go beyond building bumpers and light tabs (which is just fine if you don’t), knowing how to design parts for their intended application before you even lay down the first bead is vital.
Don’t Use A Daily Driver:
If you are like most of us when we were younger, you might want to turn your daily driver into your project truck. However, Troy strongly advised against that and said, “Don’t start with a daily driver because it will never turn out the way you want it. There are too many junkyards around that will sell you a cab and a frame for about $4,500. That’s fairly cheap when you compare it to a truck you drive back and forth to work everyday.”