3 tanks of Argon later...

I'm willing to bet that the real answer for the extra long tubes is either so you can weld on them without chasing a tube blowout or because alignment and precision cutting of the tube isn't important and oversize makes it easier.

Congrats on the welding job, that picture could arguably be put in textbook! Your welder must have some experience, how much? That jig must be awesome to weld in, so much access to everything.

What was your technique for cleaning? This is my first year welding a frame so I'm curious. Since we use hot rolled frame tubing, to clean our frame tubes we just took some sandpaper to the outside until the metal was shiny then wiped them down with some acetone or alcohol. I started using ER70S-6 filler with 23 CFH of argon, the larger size cup and thoriated tungsten. That welded fine until something caused some porosity. I checked all the seals in the torch and they all looked fine.

So I switched to ER70S-2 filler since, I understand, the chemistry of that filler to be more resistant to contamination. That helped but I still had an occasional porous weld. So I thought well maybe I'm drawing some contaminants from the inside of the tube through. I remembered watching this video where some welding guru used Muratic Acid to clean the joint to be welded so I figured I try that.

That helped allot and made some sweet looking parts. So clean!! However, still a couple times I had a porous weld. By this point I'm getting pissed and decided that even though I'm not excited about the idea I'll just go ahead and take a wire wheel to each joint. I'm welding steel here so a wire wheel shouldn't get steel contaminated like aluminum would. Since then I haven't had problems with porosity.

Schooter,

Thanks for the info. We've definitely had a few frustrations with coping tubes also. If we would've had our design done a few weeks earlier we would've had all the tubes laser notched by a company we work with. Our Formula team did it with their frame and it came out awesome. No coping, grinding or tubes flying across the floor. You just get them jigged up and start tacking them together.

I've already used the technique, on other projects, with drilling a small hole to allow the gas to flow. Our frame is still has most of the jig around it so most of the tubes are not yet sealed. I've done a few over-head welds but I don't feel like doing a whole frame worth of them.

I'll see if I can get some pics and start a new thread. I got some knuckles that are turning out sweet. Frame should be out of the jig this weekend too.

Well got lots more welding done. Our rear suspension is pretty much done, we just need to stake the bearings in.

Knuckle being welded:


Finished product:


Lower a-arm being tested. It'll move 18" before binding, so was pretty happy with that.

No the motor mounts are far from done in that picture. We re-enforced them while putting in the transaxle mount. Really right now there isn't going to be a rolling chassis step. Transaxle and motor are in already, just waiting for the rear suspension to get finished. We have all the arms welded and knuckles, we just need to get the bearings staked.

Seat is done, pedal assembly needs to be welded and the steering just needs a little support. With the u-joint in there, it has a bad tendency to bind. I'll nab my camera and get some pictures. Earlier today we got all the bearings in and all the suspension is on the car.

SEXY...we are at the same stage, parts for the transmission getting splined and then they re to the heat treaments. 

Originally posted by neilan Ok tom i think we have teased enough. time to make them wait until competition...

Party pooper!

You shouldn't worry about people copying your design, because you guys need more competition.

The emoticons are soooo gay here......