How to Make a Custom Rear Tube Bumper

Welcome to Matt’s Metalworking, in this video I will be showing you how to fabricate a custom tube bumper. The bumper on the rear of this Tacoma has seen better days, a new aftermarket non-chrome replacement is over $250, I built this for under $75 in materials plus time.

Supplies

-2x6 steel tubing, 3/16” thickness, about 55" in length

-1/4" thick channel large enough for the length plates

-3/16" steel plate

-led lights

-waterproof connectors

-fluxcore mig welding machine

-angle grinder with grinding and cutting disks

-acetylene torch

-c and f clamps

-wire brush

-hammer

-center punch

-center drill

-drill bits

-wedge

-scriber

-ruler

-tape measure

-paint

-primer

-rock guard or box liner spray

-sandpaper

-welding shield

-welding gloves

-welding coat

-ear plugs

-safety glasses

-ratchet and socket set

-wire cutters/stripers

-wire terminal crimpers

-electrical tape

-split loop wire casing

-tape

-cutting fluid

-degreaser

-painter's tape

Step 1: Removing the Old Bumper

As you can see the old bumper is badly rusted and in need of a replacement. Bumper removal procedures will vary between vehicles. For this specific truck, you may be required to elevate the rear, depending on if you have a 4wd or 2wd truck. This is a 4wd, so there’s plenty of room to get under the truck.

I’ve already gone ahead and removed the license plate. Next is disconnecting the license plate lights. You can probably reach around and twist the lights out, however they only help in with two phillips screws each. Remove the light assembly and then twist the lights out on the rear.

There will be four bolts in total which hold on the bumper brackets to the frame. This is my preferred route to remove the bumper. However, you can disconnect the bumper at the end of the brackets and I’ll show you this further on in the video. The hitch doesn’t allow for easy access to the bolts at the bumper, so the frame connection is easier.

The rear bolts are seized so I had to use a torch to heat them. When using a torch, be extremely careful around the rear light harness that runs on top of the frame rail on the driver’s side.

The bolts farthest away from the bumper go into a welded in the nut on the frame. These only need to be backed out about a 1/2” at the very most as they fit into an open slotted hole on the brackets. The bolts closest to the bumper use a nut and this will need to be held and removed completely. All bolts and nuts are 20mm.

Step 2: Laying Out the Design

To start, I have a piece of 2x6 steel tubing, 3/16” thickness. I would have preferred 1/8” but this is all they had in stock and this is rather a large step up compared to the factory chrome bumper which is 1/16” thick at best. The total width is 54 1/8”, thankfully the metal supplier I purchase my materials from cut the ends square so there’s no need to make any adjustments. I also have some 1/4” channel for the license plate area and this will get cut down, one flange will be removed, and it’ll get squared up.

Spray paint was used to mark out my cut areas so my scriber lines are easier to see. Triangular sections were cut from the ends so the bottom edge could be folded in.

Step 3: Drill and Cutting

The one cut will run a 1/4” in from the bottom edge for a total length of 10”. Making another cut line over on the outside edge, then meeting at the intersection point. This addition line is 1 1/4” above the 1/4” line. These portions will be bent into place using a torch with clamps.

The corners were drilled to make a clean intersection point for the corners, this also helps ensure a symmetrical bend. The drill points were marked using a center punch, then a center drill was used, and a finalized hole was drilled which will be filled up with weld after.

Cut the marked out portions with an angle grinder and cutting disk using the appropriate safety equipment. I did find the tubing to be slightly under tension so be careful if the cutting disk grabs.

Step 4: License Plate Area

Working with the channel for the license plate backer plate, this will be recessed into the tubing. The channel had paint applied so I was able to see my layout and it was cut to size using the angle grinder. Any cuts were cleaned up using the grinder, make sure all the edges are square.

Centering up the channel with the bumper, this will help determine my cuts for the recesses license plate area. Filler plates will also be cut out from the same 3/16” steel for the openings beside the license plate area, first is making cardboard templates and then transferring the shape over on metal.

Step 5: Bending and Templates

Using the F clamps, pull in the edges. A torch was also used on the bend points, this will help keep the steel's shape and reduce its tension afterwards. Cardboard templates were then made for the filler pieces along each side of the license plate area. This was then traced out on 3/16" steel place and it was cut to size.

The license plate channel has the edges chamfered for welding, this helps with penetration and keeps the welds flush so the section can easily fit inside the tubing.

Step 6: Welding, Welding, and More Welding

Any spots which will be welded had the rust, paint, and mill scale removed using a cup wire wheel on an angle grinder. To weld, I’m using a fluxcore mig welder equipped with 0.035 wire. Next is clamping down the ends of the tubing and welding everything into place. With the tension on the tubing after cutting, I found the walls to flare out slide, using a c-clamp helped pullback in the walls. As long one is flush, weld that one into place first and then make adjustments to the opposite side as one is fixed into position. Using the f-clamps, these will pull the cut portions into place.

Cleaning the inside of the tubing was at the license plate cutout. The areas were sanding down with 220 grit sandpaper and then degreased using a wax and grease remover. Then a weld thru primer was applied so it has some form of rust protection inside. The same process was also applied to the rear of the license plate area.

The edges of the open was chamfered to help with penetration. Clamping the license plate backer into place. First tacking everything in place, this time I’m not using stick welds just in case something pulls out of place from the heat, then it’s solid welded.

Step 7: Finish Grinding and Drilling

All my welds are ground down so everything is smooth for a seamless look. If you notice any pockets in your welds, those will need to be filled. If any lines are found in areas where two pieces of metal meet, that means you either missed the area or the weld didn’t have enough penetration so those will need to have beads applied too. Once the areas have been roughed in, you can finish up with a file. The file can level out the surface, even clean up the radius and remove any rough marks from the grinder.

Due to the Tacoma’s oddly shaped corners on the box, I can’t push the bumper in flush for more of a roll pan type look. In order to tackle this design, I decided to pull in the outside corners of the bumper on the rear. The ends will be cut a total of 6” in, then a 1/4” of material will be removed on the bottom, allowing me to pull the bumper in about a 1/4”. I’m trying to avoid adding in any filler plates for this.

Step 8: Finalizing the Design

Clamping the ends in place, this will allow me to make filler plates before taking out the welder again. As a little trick for making a template for caps. Place cardboard over the holes where the template is required, then using a hammer, tap around the end. The edge of the steel will give the cardboard a clean-cut and it’ll create the exact size. A similar method like this is used for creating gaskets.

Using the cutout section from the license plate area, this is the same thickness of steel and the templates can be traced, then cut out.

Due to local laws, I am required to have license plate lights and I want to keep them a low profile to match the rest of the bumper design. I probably could have used the old light mounts and this can certainly be an option if you want an alternative route. Marking out the holes, with the angle, I picked the wider surface as the lights are just over 1” in diameter with the rubber grommets. There will be a light on each side.

The centers were marking using a center punch so the drill bit doesn’t wander. Cutting oil can be used here, first drilling the holes using a center bit. These could have been drill before everything was welded in place, but metal can move with welding if it’s not secured fully.

Applying more cutting oil and then using a step drill. The step drill does just fine with the 3/16” thick steel and can cut a very smooth hole. With the ends still open and no end caps welded in place, I can clean out any chips from drilling.

The wiring will run inside of the tubing for the license plate lights, a hole will need to be made on the rear. Again marking out the holes using a square and scriber. These holes are slightly higher than where the holes for the lights are. Don’t make them too far off as it will be harder to route the wiring through.

Again the holes were marked with a centerpunch, then center drilled, and finally drilled to the correct size. Rubber grommets will be installed as a form of protection for the wires. These holes won’t be sealed up with a solid grommet, so I’ll also have drain holes in the bumper.

And finally is marking out the drain holes.

Then drilling them. These could have plastic caps installed if you wish, as mentioned earlier I’ll apply an oil spray inside the tubing as a form of protection against rust.

Any spots or parts that will be welded were cleaned up using the wire wheel, removing any rust, paint, and mill scale. F clamps were used to pull the ends together. It’s only a small bend so a torch wasn’t needed.

Measurements were taken to verify both sides are the same and tack the pieces into place.

Removing the clamps and then it can be solid welded. The gap isn’t overly big, taking my time, I can fill it in with weld. The torch isn’t angled towards the hole, but instead between the weld and edges of the cuts. If your angle is wrong, this will just burn out of the edges of the cuts instead, making the gap larger.

Allowing the welded portion to cool down, when the steel temperature keeps increasing, there’s a greater risk of burn through.

Running another bead on another portion.

Cleaning up those welds with a wire brush, removing any slag.

Finishing up that bead, this bead won’t be ground down and instead will be left as is other than cleaning it up with a wire wheel. The very corner I left again to cool down as it’s the largest area so I don’t want it overheating where it burns away the material.

For the end caps, the edges were slightly chamfered and I used a magnet to hold the caps into place.

The caps were first tacked into place only at the furthest ends closest to the corners.

Then full beads were applied on the ends. I did find the tubing was slightly bowed outward, a clamp was used to square everything up again, then it was welded solid.

Moving over to the opposite side. Pushing the sliced portion down with the f clamps. Tack welds were applied to hole everything in place.

Then that gap was closed up, for an additional angle, you can see the angle of my torch and the weaving motion. The weaving motion gets wider as I work my way to the larger gap.

While it’s cooling down, the end way was installed.

Tacking the cap into place, this side wasn’t bowed out so no clamp was needed.

And the end cap welds and weld at the bottom of the bumper were ground smooth. The large gap weld was left as is but just cleaned up with a wire wheel.

Step 9: Fitment

Next is cutting the bumper brackets to size, they were removed from the factory bumper. On the Tacoma, they bolt into place. The brackets were installed back onto the truck and as you can see, they do stick out quite a ways. Using the straight edge, I applied tape to the edge so it wouldn’t scratch the paint.

Then I applied more tape to the box to protect the paint when test fitting the bumper. Using the square, making a reference straight down to the bracket. I’m hoping the position of the tailgate is fairly accurate. A scriber is used to mark down lines from the tailgate.

I also used whatever I could find lying around for a straight edge to make another reference mark of those portions of the box body. It’s better to have the brackets longer and grinder off a small amount of material at a time instead of cutting too much material.

Cutting down the brackets using the angle grinder. Making custom brackets is certainly an option, while these do have some rust, it’s only superficial. These will be cleaned up with a wire wheel and painted. After that, the brackets were reinstalled onto the truck. They do have a bit of movement with the elongated holes, I pushed them as far forward as possible. If the space is tight between the bumper and box, I can pull the bumper out slightly.

With a couple of slight adjustments using a file, I was happy with the fitment and it’s ready to weld into place. The brackets and the areas where they’re welded to were cleaning up with a wire wheel. I used the f clamp to hold the bumper in position and it’s balanced on the hitch with a spacer block. I also made sure there’s enough room for the spare tire cable drive cutout area.

Right now I just stitched the bumper brackets into place and a final weld will be done when it’s removed so I have enough room to work.

Step 10: Bumper Brackets

Now the bumper can be removed and the brackets can be fully welded. There may be some movement so it’s important to test fit this again after all the welded is done and make adjustments as needed.

In order to add some strength to the brackets, I cut some gussets from what was left of the license plate area. The corners won’t be fully welded as this is a ledge where dirt or debris can get trapped and may not always wash out.

First is tacking the gussets into place, clean up the welds with a wire brush and finish fully welding the brackets and guss

Step 11: Prepping for Paint

Moving onto the finishing stage. The mill scale can be left on if you wish, but it may not be smooth, not allowing for a clean final paint finish. Mill scale may even chip off after it’s been painted. A wire wheel can be used, with a larger area it’s time-consuming and a bit more work-intensive.

To remove the mill scale, I’m using muriatic acid. First is mixing up a neutralizer with a bottle of water and baking soda added in. I would say there are about two to three tablespoons of baking soda added for 500ml of water. Then shake the mixture up, ensuring it’s mixed.

For the acid, when mixing, add acid to the water instead of water to acid. This will prevent the acid from causing a reaction where it splashes out, harming yourself. When working with acid, it’s extremely important to wear the proper rubber gloves, extra protective clothing with no exposed skin, safety glasses, a respirator, and work in a well-ventilated environment. I have 2/3 water and 1/3 acid.

The area should be free of any oil, there is a small pinhole in the lid of the bottle, apply it to the surface. The surface can be agitated using a wire brush. In about 5 minutes, you should notice the steel’s surface cleaning up.

When you’re satisfied with the stripping of the surface, the acid can be washed away. Neutralizing the acid, pour the baking soda and water mixture onto the surface. You’ll notice the acid foam up which is normal.

Allow it to sit for a moment and then rinse off the surface with clean water.

Flipping over the bumper, you can see where the acid dripped on the side and bottom shown by the clean areas.

Do the same process on the opposite side. The acid will strip everything from the paint, rust, and mill scale. When it’s done, the surface should be dried off immediately to prevent flash rusting. I wasn’t able to do this as it started raining right after flipping the bumper over.

Overnight you can see the flash rusting was is fairly superficial and can be cleaning up with a wire wheel on the angle grinder.

Step 12: License Plate Holes

Before paint, I marked out the license plate mounting holes.

Next was drilling the holes, using a tap and die chart I drilled them out to the correct size for the tape I wanted to use.

Apply cutting oil and finally taping the holes. This is 1/4” thick steel so this should be plenty of material for threaded holes. An alternative route can be nutserts or welding in nuts behind the backer plate. That cutting oil will need to be cleaned off using a wax and grease remover.

Any holes or edges were cleaning up with a file. I made sure there were no burs inside the light mounting holes too.

The metal was sanded using 320 grit sandpaper. I won’t be using a filler primer here. A filler primer and even filler can be used to hide any imperfections if you desire.

Clean up the surface using a wax and grease remover. All contaminants must be removed so there are no issues with the primer and paint.

Step 13: Paint

As for a primer, I’m using an etching primer which helps cut into the metal. Typically you can’t paint over an etching primer as it can have chemical reactions with paint. However, this etching primer allows for paint topcoats.

For paint on the rear, I’m using a farm implement paint. I purchased this from the local farm equipment dealer, I do use the brush on version quite a bit and am extremely happy with its stretch and durability. This is their spray paint version with a low gloss finish. Road debris won’t stick easily to the smooth paint unlike a bed-liner coating but still provides excellent protection. Once this paint is dry, the bed-liner spray will be faded around the edges and visible on the outside edges.

I picked up some bed-liner coating from the local hardware store, one can be plenty. I was having some spraying issues with the can, it would only spray upside down and I’m fairly sure it wasn’t supposed to do that. Three light coats were applied, this coating dries very fast, and does leave a great texture.

After 24hrs of fully drying, here’s the bumper before it goes onto the truck.

On the rear, I installed the rubber grommets. Considering it’s cold out, I let them soak in hot water for a few minutes so they’re soft, making them easy to install.

Step 14: License Plate Lights

Next is installing the lights. They clip into rubber grommets, the grommets were installed first, the wiring was fed through the holes and then the lights were pushed into place. I purchased these lights online from Amazon. They came in a pack of 10, couldn’t find anything smaller quantity-wise. They worked out to about $1.25 each. There are two lights, one on each side.

I installed weatherproof connectors and a special crimping tool is required for these. They have rubber gaskets so water or moisture can’t penetrate the terminals.

Step 15: Modifying the Wiring on the Truck

On the truck, the old light connector was cut off and I installed the other side of the weatherproof connectors. Being that I am using led lights, these typically only work one way with the anode and cathode. I tested them out first to determine was side was positive and negative.

Step 16: Installation

Installing the bumper into place, tighten the bolts as needed and make sure it's in the proper location. Some factory bumper brackets do have mild adjustments.

All the wiring was cleaned up, cable tying everything into place so it’s not tangled up with the bumper and is ran up close to the body, out of the way from anything that can damage it.

Plugging in the lights, testing them out to make sure they work. And finally tying those connectors back under the truck.

Step 17: All Done!

And once done, here you can see the finalized bumper. I still need to reinstall the hitch after it’s been painted. I couldn’t be happier how it turned out, a low profile bumper that should be much stronger than the original version. While it doesn’t have a step anymore, I could always have a step insert for the hitch. Additional features could be added if you wish such as tow loops, flush mounting reverse lights, a hitch receiver, etc.

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