Chevy truck rear bumper build

[oil pan 4]

The pickup truck bumper I have on there right now is starting to get kind of rusted out. It always had a few things I didn't like about it. The aero dynamic profile is like a metal parachute and its thin stamped chrome plated sheet metal. The chrome is slippery when wet. This build will not have any of the spy car stuff like the front bumper here http://ecomodder.com/forum/showthrea...ild-33370.html

The metal parachute..




The fit wasn't perfect but I liked it enough to use it. No it was not a direct bolt on, I had to modify the suburban frame with my plasma cutter to make the bumper fit.

My requirements are:
Make it heavy, since this is a rear wheel drive only vehicle
Stainless steel diamond tread, because that's what I like
Build it to the existing frame as much as possible, modify the frame as needed
Build it around the class 4 weight distribution hitch
Bolt the bumper to both the frame and distribution hitch for ultimate strength
Bolted not welded to the frame or hitch so I can remove it for modification or repair.
Aerodynamic profile better than the current disaster
Additional reverse light
Place for license plate
License plate light
Storage box for flat 4 connector

This is kind of what I want it to look like,


The class 4 hitch.


I can make it fit close to the body and have it look a little better and be a little more aero.

What do we think would make the best shape to put on the outer edges of the bumper?

Projected start date is august. I am running low on 1/8 and 1/4 inch thick diamond tread and don't want to pay retail prices for it.
This way I have plenty of time to iron out the design and collect materials.

[kach22i]

You could screw or rivet a flat sheet of plastic (PVC, ABS or polystyrene) to both the body and the bumper.

For that matter, sheet metal with folded over edges would also work.

If you want to get fancy, a foam plug covered in fiberglass would be the slickest.

EDIT: There is this 911 project of interest (welded aluminum).
http://forums.pelicanparts.com/porsc...1s-1977-a.html

[oil pan 4]

That guy likes aluminum about as much as I like stainless.

Making the transition between the body and bumper like they did on that Porsche.

I am building a whole new bumper, not modifying the one in the picture, it has a few holes rusted in it. I sand blasted the scaly rust off 4 years ago and painted over it and that left the steel pretty thin in a few spots and the water found a way to get back into the metal.

[aerohead]

I'd consider making a deeper bumper with the bottom aligning with a future 2.5-degree diffuser projecting off the bottom of the rear axle line.Rocker panel extensions behind the rear wheels would blend into the deeper bumper.

[oil pan 4]

Since this build will be made with much thicker stainless joints.
On the front bumper build the heaviest joint was just a 1/4 to 1/4 inch butt weld, my little 105 amp home made tig welder was just barely able to weld that.
The heaviest corner joint was 1/8 to 1/8 and the 105 amp tig was able to weld this with ease just from one side.

On the rear bumper I will be welding at least 1/4 to 1/4 inch almost every where. But could be as thick as 3/8 or 10mm, just depending on what shows up at the scrap yard, I am not paying retail for 1/4 inch stainless diamond tread, it is rather expansive and I am rather cheap.
And I am going to weld both sides for maximum strength. Getting into that 90 degree corner is going to be kind of tough, its going to be really difficult if the machine I use cant provide enough power to melt the 2 sides of 1/4 inch or thicker plate.

So I am eyeing my 230 amp craftsman welder to be converted to tig.
Really the only thing keeping me from using the full power of the craftsman is my air cooled WP-17 tig torch, its only rated for 150 amps DC and 115 amps AC. I have read the WP-17 torches fail spectacularly if you give them more than 200 amps. I am too cheap to blow up my perfectly good WP-17 and have to replace it and still have to buy an appropriate torch.
Also 105 amps AC seems to be the practice limit of what the WP-17 can handle, it heats up quick and burns up collets with ease.

So I am thinking I will get a WP-18 torch. Its water cooled and rated for 350 amps at 100% duty cycle and 250 amp AC 100% duty cycle.
Then use my http://ecomodder.com/forum/showthrea...ing-32417.html cooler-pumping unit as my torch cooler because I am cheap.
I am not spending hundreds upon hundreds of dollars on a torch cooler.
Why a 350 amp 100% duty cycle torch on a 230 amp machine? Because I may want to combine the DC outputs of both welding machines, which could add up to right around 350 amps and 230 amps AC is awfully close to the 250 amp AC limit.

[gumby79]

Some pictures , with a 1'ruler in pictures for scale references, burb without the bumper would help the community to provide useful design ideas.
I'm extremely interested in this build as my'91 Dodge D250 has the same problem bumpers sticking out 3-5"past the sheet metal.
Gumby stay flexible.

[oil pan 4]

This is what I would like to avoid.
Happened to a 10th generation 3/4 ton suburban.



I believe this was a class 3 hitch, I have a class 4.

[gumby79]

Oil pan did the frame fail or is that a bumper mounted receiver class 1-2? What ever the case, it was eather in an accident or a gross over load for no Wight distribution/ load leveling hitch. Win I worked at U-haul 1999-2000 I had a customer with a cl4 in this condition. His wife rear-ended his travle trailer with wight distribution hitch and folded the hitch ,bumper, and frame under the back of the truck. Looked just like that.

[oil pan 4]

Well that would be my luck then.

[oil pan 4]

Here is another one.
This one comes with a little back story. The guy said he accidently put about 4,000 pounds of tongue weight on his pickup while loading a trailer. Oops.