Hi, I am interested in this too. I have done a lot of TIG welding over the years mostly on racing bicycles and the one thing I know is that along with the tensile strength going down when you weld on aluminum the fatigue life goes down too. However, from my personal experience if the wall of the tubing is thick enough that overcomes the fatigue problem. Someone mentioned heating and quenching the 6061-T6 to reharden the aluminum, but this is not the case. When Aluminum is hardened it is first heated to almost the melting temp which allows the metal to shift around to relieve the stresses and then when you quench it, the aluminum is actually softened. To harden it back up you heat it somewhere around 3 to 400 degrees F and then let it air cool, this returns the temper to the aluminum.
One other thing of note that I am sure you know is that aluminum grows quite a bit when you weld on it. This too can cause problems in that if you weld on one side of a joint and then let it cool and go back later and weld on the other side of the joint you induce stress into the joint. The best example of this that I remember is the early Canondale bicycles where they mounted the tubes in a jig and welded one side first, then waited for the frame to cool and then remounted the frame in the jib with the other side up to weld the other side. This induced a lot of stress in the joints and then when they went back and heat treated the frames they would mount the important points like the drop out, the head set points and the bottom bracket in a steel frame so that they would not move. They would then put it in the over and heat it to near melting temp to allow the stresses to relieve and the smaller tubes on the frame would twist as the stresses were relieved. All of the key points were in perfect alignment, but the tubing to them were twisted. After quenching then they did the heat treating to return the temper.
I am not saying you don't know about this, it is just something for others to understand about welding aluminum.
On your frames since most people do not have a TIG welder available are there going to be generic mounting points that people can build engine and tranny mounts to fit to the frame and to the engine for a swap?
When Aluminum is hardened it is first heated to almost the melting temp which allows the metal to shift around
This is called "solutionizing". It's the aluminum equivalent of annealing steel and results in a uniform distribution of the alloying element atoms throughout the aluminum matrix.
The T6 heat treatment is elevated temperature aging to maximum strength... only a few hundred degrees, as you mentioned.
[This message has been edited by Will (edited 11-04-2012).]
Well there is definitely a market as a customer asked me to do this very thing for his car. However I took it upon myself to upgrade his suspension while I was at it which in retrospect was a much larger job than I originally anticipated as I'm still not complete. I'm using 2"x3" x .188 wall, 6061. I'm already off topic so.....
a very good option for owners who want to upgrade their suspensions, remember that 88 suspensions/cradles are now 27 years old. reminds me of the post several years ago of a person in west central florida offering hand made aluminum fuel tanks, everyone said WOW count me in, i think he said he's sold three. there are more people that need a new fuel tank more than a suspension upgrade.
Well, when I think aluminum my primary interest would be in weight-savings and it turns out that the fuel tank wasn't any lighter than stock so why go thru the trouble for an extra gallon or two of gas?
I'd replace every piece of steel in my car with aluminum if it made sense to.
Hell yeah. We have been needing a modular cradle for years. This would make swaps so much easier. Can you imagine all the extra room we would have around the drivetrain? Plus, its just a matter of adding the correct mounting points for the various drivetrain combinations. The possibilities... WOW Ring ring.. yes, I need a cradle for a 88 running an L67/F40 or 4.9/4T60 or ECOTEC/F23..... Oh my ! I'd be in even if it was just tubular steel, actually, I'd prefer it.
This right here. If there was an '88 cradle for an '87 body that was ready for either an LSx or high value with some F-series transmission, I'd buy one tomorrow.
