So you’ve got a set of pipes you and your buddies whipped up with a Biltwell builders Kit, or some scrap bends you had kicking around, and they are rad….. but they just need a little something extra in the style department. Not to mention, no longer burning your leg at traffic lights would be a bonus….. So what do you do? Order a chrome universal heat shield? Maybe, but if you’ve already come this far, and already put your own sweat and blood into your pipes, why cop out now!? Building yourself a set of custom heat-shields would be the proper happy ending to this journey. And it’s easy!
Angle Grinder with cut off wheel
Drill Press –or-Hand Drill-or-Knee Mill
Drill Bits (.25”)
Hole Saw (1”)
File / de-burring knife
Belt Sander/Flap wheel
Chip Board( non-corrugated cardboard) / OR a Cad program if you’re a tech genius?
¼”-20 x .25” long Button Heads
Tubing .25” larger in Diameter than the exhaust pipe you are making the shields for.
First you need to decide what type of material you would like to use for your shields. You have several options, the most common being mild steel, stainless steel and brass. All of those options are available in tube form, and in outside diameters that will work with common exhaust tube sizes. So pick your material… if you plan to coat them in the end (ie: chrome, ceramic coat, high-temp paint, etc), mild steel will be a suitable choice. . It’s easy to attain, work with and cheap.
If you do not want to use a coating, Stainless steel is good choice. It’s usually a special order item, but available. It will do the job well, can be polished or left raw, and will never corrode. You should note that it will be a little tougher to work with than other materials.
Lastly, if you’re running copper oil lines and have some brass bits accenting your bike, then brass tubing may be the right choice for your scoot. It is durable, corrosion resistant and nice looking. It’s also easy to work with.
The tube size you pick to make your shields will be dependent on the outside diameter of the exhaust pipes you’re working with. I generally pick a tube size that is .25” larger in diameter than the exhaust tubing. The ratio of the pipes nested together always looks good, allows enough room to let the heat shield actually be effective, and also leaves room for heat wrap should you desire it. So if your pipes are 1.75” in diameter, (which is a common size for HD) then go with a 2” heat shield tube.
For this demo, we are using brass per the requests of the customer. The pipes on his bike were built by a friend of his, out of scrap bends they had. He likes them, but wants to heat wrap them and add some additional brass accents to the bike at the same time. So we chose 2” brass tube and are going to make a set of 6” or so long shields that will fit over the wrap, and will have a speed-hole type design.
For the layout, if you have some type of cad/ drawing program that can print to scale, you can use that to make a template.
Or you can use some basic measuring tools and draw one.
To do this I set up a paper template with my mounting hole spacing and then whatever other design I want to include. For the “speed” hole design, I will mark out the center point of where each hole will go, then mark where the outside edges of each hole will be. Once those are placed, I use a compass to see how the layout looks. If I like it, which I do, I move on to the shape of the outside edge. In most cases, the best looking option will be oval shaped.
To do this, take a bit of thin, non-corrugated cardboard, ( like the kind that comes in gasket kits and other flat packaged bike parts) and starting with 1 straight edge, make a center line, fold on that center line, and then cut a rough “half oval” with it. Once you have the rough shape, you can hone it in to fit over you layout until it looks how you want. (To save some struggle when mounting the shields, keep the mounting hole location close enough to the edge of the shield that you can get behind them with your welder to get a small tack on the mounting nuts.)
Keep in mind, if you wish to get two shields from one section of tubing, DO NOT have the width of the oval be greater than half the circumference of the tube!
(Circumference is the linear distance around the edge of a closed curve or circular object and is found by multiplying the diameter of the tube by 3.14(pi))
In this case the width of my oval is about 2.875”. Since our pipe is 2”, it makes for easy math: 2” x 3.14 is 6.28”... but you don’t really need to do the equation in this case because you only wanted to know HALF of the circumference, which in this case is 3.14”, and is greater than the width of the oval I drew, so I will be able to get TWO shields out o f one section of tubing.
I will use this to transfer onto the tube, by cutting out the template and taping it to the tube. I then center punch the centers of each hole, as well as tracing the outer profile onto the tube. The next step is to drill and cut all the holes. I set the tube up so that I end up doing both sides at once in the Bridgeport. You can do this in a drill press, oh hand drill as well, provided you use a suitable vice, and are super careful.
Depending on how you wish to mount you head-shield, and how you want it to look, your choice for holes sizes will vary. I use 1/4” button heads for mounting mine, and use a 1” hole saw for the larger holes. Start all the holes with a center drill to prevent walking, and then use the appropriate sized drill bit for your mounting holes. For the larger holes make sure you use a hole saw with a centering drill bit.) Go slowly as you make you cut, using a spindle RPM of no more than 300rpm. Lubricate with DW40,and continue cutting until all the way through.
(If using the hand drill method with the hole saw, don’t try and stop when you think your getting close, just keep going at a steady speed until all the way through. Otherwise the hole saw can and probably will catch and could seriously hurt you, and ruin your part! This applies to hole-sawing in any type of sheet metal by hand. You will also probably want to drill each side of the tube independently. )
Once your holes are drilled and cut, I recommend de-burring them as much as possible before you move on. It’s just easier to hold the tube while it is still in tube form, and with fewer burrs, you run less risk of cutting yourself while performing the remaining steps in the process. So using a file, a de-burring knife or a countersink, take off all the burrs you can get to.
Once you’ve done that, it’s time to move onto shaping the outside edges of the shield. This part is more subjective, but if you made yourself a good template, that is symmetrical and even, it will be much easier. Cut the tube in half with a cut off wheel. Then work yourself around the outside edge of each shield carefully. After you have roughed out the shape, you can clean it up on a sander, a flap wheel or even files, and now you can also get the rest of the burrs you couldn’t reach before.
With the shields themselves done, its time to pick your mounting location on the actual pipes. For this set, I wanted them to be located in the foot-on-the-ground position. I also wanted to push the upper shield as far forward as I could, and had to do a little shrinking, hammer and dolly work to the leading edge to get it to “cup” the bend a bit better.
Once you have an idea of where you’d like them to be, put a bolt and nut in each mounting hole, grab a few wire ties and mock the shields up. I actually use the ¼”-20 nut as the threaded mount for these too, so once you get them where you like, tack the nuts in place! ( If you have properly planned your layout, you should have enough room to sneak a tack with a TIG or MIG welder .)
After that, all you have to do it finish weld the nuts, and perform any other cosmetic work you’d like to do. In this case, we gave the shields a scotch-brite treatment, and wrapped the pipes in black heat wrap.
In this photo you can see the extra work to the upper shield.
And here is a set done the same way, but in Stainless Steel.
That’s all there is to it! Obviously you can change up the overall design on your shields, making them longer, shorter, wider, and giving them different designs. You can cut more holes, less holes, no holes, fins, ribs, welded details, anything you want! Hell, we have even made them out of stainless round bar! Just have fun and keep on choppin!!