|07-10-2013 07:49 PM|
Nice to hear from a fellow engineer! I'm currently still in school for mechanical engineering, minor in manufacturing.
That is some great info and I'll be sure to use your mock-up idea. So far I really like the rough country style stubby bumper, however, the one that accomadates the winch is 2x the price of the one that doesn't. I plan on building mine like the one that doesn't allow a winch, but fabbing it so it can mount one in the future if I decide to do so. Also, I found jeeptubes.com sells pre-made stinger bars that I think I'll order and weld on the top. I still have to figure out the d-ring setup.
Looking forward to seeing how your bumper turns out!
|07-10-2013 07:40 PM|
Robertsk1, I am in a very similar state with the front bumper on my 05. I really like the look of the poison spider for the jk but its not made for the tj, even if I could afford it. 1st off, I'd suggest doing a mock-up using something cheap like door skin or heavy cardboard. I did that and found what looked good in my head didn't look so good in 3d. I am in the re-think mode right now. So even though the mock-up didn't look too good, it was a lot cheaper and easy to learn that with door skin and duct tape than in metal.
As to mixing metals, I would be leery about that. Galvanic corrosion is never too far behind mixed metals... I'm an engineer and have had to do too many repairs to structures and equipment where things corroded due to mixed metal. If you must, then think electrical isolation between dissimilar metals.
As to thickness, that depends on what you are asking the bumper to do . If you're looking for a crumple zone (like the factory) 1/8th steel or 3/16 Alum would probably be ok. If you want a winch mount and the ability to take a hit with little to no damage, 1/4" steel or 3/8 to 1/2 Alum would be better. Of course, with Aluminum, the alloy will make a big difference in how thick a section you'll need. Only thing is harder and stronger alloys are usually harder to fab and correctly weld
The truth about Aluminum vs Steel in the weight department is while Aluminum is lighter per cuft, it's also weaker and usually takes more to have the same strength as Steel unless you have access to some of the more exotic aircraft alloys. Even if you do, they will be harder to repair when the inevitable trail rash happens.
That's why I decided to stick with steel. My design is starting with a pre-made winch plate that has an integrated fairlead mount and growing from there. Most of mine will be fabricated from 3/16" as i feel that will give me a good balance between weight and strength. I may use some 1/4" stock and some internal gussets if need for added strength or rigidity...
Sorry I can't seem to find my 1st round of mock-up pics but it i do I will post a few.. It's good to see someone else who's looking to do something home fab for a front bumper. If i get the front figured out, I also plan to do a rear with swing out tire carrier...
|07-10-2013 06:51 PM|
My bumper build thread
A little background: I bought the jeep a while back and it came with a generic brand smittybilt style bumper. I loved it, at the time, but it's losing its appeal. The weight and bulkiness of it is getting old. Also, just something about inherting a jeep with a nice bumper on the front feels wrong I'll soon be parting ways with it and handing it off to a fellow CT jeeper who seems more than happy to take it off my hands for a modest sum.
So I've been bopping around the internet for different alternatives to my soon-to-be naked front end. I love the poison spyder and metalcloak bumpers, but just can't justify spending that much cash on a hunk of well-worked metal. I'm pretty cheap when it comes to this stuff (and you'd wonder why I bought a jeep ).
All of the bumpers I've seriously considered have been $250+ which just doesn't fly with me. So I'm now entertaining the idea of fabbing up my own bumper. I'm thinking of doing a medium sized stubby bumper with a stinger on the front and a pair of through-mounted d-ring shackles. I'd like to shed some weight by using aluminum as much as possible.
I have machine shop experience, and currently work in design at the company that develops Mastercam (CAD and CAM software), so I have limited access to cnc machines, and a good buddy of mine has offered his welding hand once I get the sections cut up.
This will take a week or so to get the ball rolling with, so bear with me, but I'll do my best to post up pictures, step-by-steps, plans, answer questions and whatnot.
A few questions for you guys:
Where should I use aluminum to strip weight and where should I NOT use aluminum to strip weight? Also what thickness/type of aluminum would you recommend?
Any tips/tricks/notes/etc.. you might have for a build of this nature?
Even if no one follows this, it may help with my sanity should I run into some snags....