4130 tubular rear subframe for my car

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Hey guys.  Myself and a buddy just finished a pretty neat project.  It's a tubular rear subframe for my AWD Mitsubishi Eclipse.  It's made of 1.25" x .065" 4130 tubing.  Building this was a great learning experience for both of us and I'm very happy with how it turned out.  Features include:*  Solid aluminum pressed into 4130 for all mounting points.*  Optional raised inboard pick-ups to raise the car's rear roll center*  Extra differential bracing to help resist twist*  All pivot points are spherical bearings, so no more rubber bushing deflection*  Saves 35.7 lbs of weight over OE stamped steel subframeEnjoy the pics!"There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:"There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:"There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:"There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:Pretty slick. Good fit-up...  I figured the square tubing was a jig, but the first pictures had me a bit leery...  Turned out nice
Reply:Thanks. "There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:i think the fit-up was more impressive than the welds.  not that teh welds were bad, they are great, but that fit up was excellant.
Reply:Thanks!  I did the designing, planning, and tube fittting myself.  Pretty much everything but the welding.  My buddy knocked out the welding for me.  He's a far more experienced welder than I am, and there were many tight and tricky places to reach into with the fixture in the way.  He did an excellent job all things considered.90% of the fitting was done by hand with an angle grinder.  You could imagine how long it took to get a perfect fit.   I really need to invest in a better tubing notcher."There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:What did you use for the design and planning phase??
Reply:Originally Posted by bottlefed89What did you use for the design and planning phase??
Reply:If I had 1% of your ability - vision I would be riding on air...Dave ReberWadsworth Ohio
Reply:Thank you sir.I'm starting the build of the fixture for the front k-member tonight.  It's going to be much more complicated than this one but I figured it would be nice to have a matching set."There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:thats rad A+CenterLine Motorsports - http://www.facebook.com/pages/Center...89516977767905
Reply:Looks very good.1G or 2G?Are you making 9 more?
Reply:Thanks.  It's for a 2G (are you a DSMer as well?).  I do plan to make a few more once this one proves itself."There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:Very very cool... I have built a few 4130 tube chassis and fit up like that isn't easy, very impressive.
Reply:I work with 4130. not as easy jigging and fixturing as it looks. it takes many hrs to do it right. Awesome job with the fixture and welding. Sweet job!!!!!
Reply:nice work! what did the laser brackets set you back?
Reply:Nice job!Do you have a particular source for the tubular bolts that you use?http://all-a-cart.comWelding Cart Kits and accessories
Reply:I'm curious as to how quickly galvanic corrosion will affect the steel tubes that the aluminum bushings are pressed into.  Give it enough time and the steel will corrode and crack like it was never there.Have we all gone mad?
Reply:very nice!
Reply:Very very nice work gentlemen, thanks for sharing
Reply:With all of those welds, my first thought was warpage, but with that awsome fit-up, I'm sure it keft it to a minimum. Nice fixture and super welds.
Reply:Wow, nice work!www.thefusionsolution.com
Reply:Thanks for the compliments.  Originally Posted by vettepickingnice work! what did the laser brackets set you back?Originally Posted by sn0border88I'm curious as to how quickly galvanic corrosion will affect the steel tubes that the aluminum bushings are pressed into.  Give it enough time and the steel will corrode and crack like it was never there.
Reply:You don't need electricity for galvanic corrosion to take place.  It's just the difference in electrical potential between the two metals.  There could definitely be an issue between the aluminum and steel like you have it.  It's not something that will happen over night, but eventually you could have a failure.  That was the only thing I noticed.  The fit up and design looks fantastic though.In your case, with the suspension getting wet, you would have water acting as your electrolyte, either from driving, or just slowly out of the air.  Have you considered using something like Delrin for the bushings?http://en.wikipedia.org/wiki/Galvanic_corrosionThe other way would be to just isolate the two by powder coating or painting the frame.  But you would have to account for that thickness by reducing the diameter of the bushings slightly.Last edited by kazlx; 03-21-2012 at 11:31 AM.
Reply:I do plan to cathodic electro primer coat and then powdercoat the entire assembly.  That should help prevent water and/or moist air from making it's way in between the aluminum and the steel.Using Delrin might be a good option.  I'll check into it."There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:I know www.maximummotorsports.com uses delrin in their arms...although they do mostly Mustangs.  You could check the site for ideas though.  I have machined a little bit of delrin and it's pretty easy, but if you are powdercoating the whole thing, you shouldn't have an issue.  You just want to stay away from metal on metal contact.
Reply:Damn Paul, that turned out great!Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Thanks paul."There are two types of people in America - those who try to classify everyone into two types and those who don't."
Reply:Galvanic corrosion is a real pain, I haven't seen many cases where susceptible pieces in close contact were able to be protected.  I would really consider looking into delrin.Have we all gone mad?
Reply:Here's some info on steel/aluminum corrosion that may help:http://www.corrosionist.com/Steel_Al...Corrosion.html- "If ya can't be handsome, ya may as well be handy!"   HTP Invertig 201Lincoln Power Mig 255CLincoln SP125+Thermal Dynamics Cutmaster 38