Seam welding the chassis

[FE3-323]

Please give your thoughts, do's/dont's, cage first/last.... proper ways of seam/stich welding

[FE3-323]

no one has any input???

[1st Gen]

I worked with a guy that swapped out the RR quarter of a Honda Civic. I had to drill out all the spot welds on both cars, he then fit the straight piece on the car he was building, then welded each hole back in with a mig welder. He kept the car on a frame rack the entire time so the integrity of the frame was kept straight. After all that, he covered the seems with seems sealer and painted it. You couldn't even tell.

What exactly do you want to know?

As for welding, short time intervals so heat doesn't build up too much. That's if your talking about body work.

[jay]

unibody cars, low heat, short intervals, inch long bead every couple inches or so seems to be the norm. Having the car on a rack would be a nice luxury as well.

[yunvmyegt]

all i wanna know is how it rides as a dd afterwords, ive thaught of doing mine if i can get it to not be sooo stiff feeling when its done.....

[MD323]

prep is your friend
prep is your friend
prep is your friend
prep is your friend

clean ALL joints 130% before ever welding a single bead. I was taught (though as far as "seam welding" goes i have only did an engine bay apillars forward) to do it with the suspension loaded and the motor/trans in. unless you have a ragged out body to start, then strip that bitch and get out the collisions diagram and bent till straight and weld.

also to 2nd jay, short welds, low heat, and space them out to avoid heat soak. you can make 4 passes at it if needed just let an area cool before laying more bead

[jay]

I can't imagine "too stiff" would be a problem, chassis designers are trying to make em as stiff as possible and make the suspension do the work instead of the chassis, things just work better that way. Show me someone who notices a difference in the way the car rides after seamweld and I'll show you a car that was way too floppy in the first place!

[MD323]

my 323 feels floppy at times

[FE3-323]

^ as does mine shawn. i've noticed flex in the chassis before just normal driving.
a cage & seamwelding the chassis are ideally what id like to accomplish.
Which should be done first? i've heard cage first then seam weld....

[MD323]

as far as improvement goes it would be cage, from legal and non dome splitter, id say seam

[SgtRauksauff]

A cage first would act as bracing for the chassis, so when you clean the seams, you don't have to worry (as much) about the car getting whacked out of shape.

That being said, Look at a good cage, and then try to fit yourself through it while trying to get good angles to weld things....

--sarge

[FE3-323]

i need a main hoop for the top bent up......

[JPmotorsports]

Just saw this thread---we've done about 8-10 through the years, mostly rallycars. The builds that are new the cars are stripped then acid dipped, seam welded on a stand/table, then caged/put back together. The others are done loaded up on level ground---we've taken the wirewheel to the seams and even had to take a chisel, spread the seams, more wire wheel then tap them back to get them clean enough. Very rarely do they weld nice, even after an acid bath...We stitch them like Jay said, about 7-10 pulse welds and then skip a couple inch's. Try an weld around the radius/corners---more on the loaded areas. The cage adds plenty of stiffness to the shell without the welding though---we have cars that constantly lift wheels in corners that they never had before without the cage. The rallycars will lift the right rear 10" coming out of the driveway at an angle in front of the shop at speed. The seamwelding/acid dipping is a pain for rust by the way---not worth it in my opinion unless the car has a short life span/duty cycle/whatever...

[nerd racing]

dang I'd love to have one of those stands... and California weather!

[FE3-323]

Jim, do you recommend staying away from fully welding the seams. I.E.> going back over the skipped portions after cool down?