Author Topic: seam welding chassis (Read 7901 times)

silvertdi · « **on:** December 30, 2007, 01:13:24 am »

Anybody seam weld or stitch weld the chassis? I'm thinking about doing the radiator support and the underbody. It will definately stiffen things up, but I've read that they could fail catastrophically. Any input? Thanks.

the caveman · « **Reply #1 on:** December 30, 2007, 05:57:47 pm »

why would it fail? i did my super beetle years ago and it is defintely stiffer than stock. did it all with a torch too. messy but fun.

blkboostedtruck · « **Reply #2 on:** December 30, 2007, 09:36:02 pm »

the only failure i see is not treating or sealing the metal from moisture after the process is done! anotherwords rust is the word a chemical reaction when water dries on steel! oxydation,steel is biodegradable!
another possible faliure is using improper welding technics , oxcy accetelyne ,braising is not recomended for use on vehicles from around 74,75 and newer because of the introduction of HSS (high strength steel) the heat produced from a torch takes out the temper or strength of the steel!
MIG or spotwelding is the recomended process you don't want to but alot of heat in the part your welding it just takes away the strength!
thanks Duane

silvertdi · « **Reply #3 on:** December 30, 2007, 10:47:54 pm »

I had read that if the weld wasn't of a high quality, and a crack started, it would migrate the length of the weld and spell trouble. I read that the autocross folks do it when the rules allow. I'd just like to strengthen the areas where I jack the car so it doesn't look so bent up and ugly.

blkboostedtruck · « **Reply #4 on:** December 31, 2007, 01:20:59 am »

well behind every weld there is a welder so the quality of the weld depends on thier knowledge and skill! i've done a little welding in my day! what area are you planning to beef up? i may be of assistance to ya and could tell you if it can be done or not?
send me a P.M.
thanks Duane

the caveman · « **Reply #5 on:** December 31, 2007, 10:17:56 am »

bikboostedtruck you are right of course about the newer steels. in the past i would have had no problem using a torch but things have changed. i welded up my beetle almost 30 years ago.

blkboostedtruck · « **Reply #6 on:** December 31, 2007, 11:00:26 am »

Quote from: "the caveman"

bikboostedtruck you are right of course about the newer steels. in the past i would have had no problem using a torch but things have changed. i welded up my beetle almost 30 years ago.

well just so you know i was not trying to shun you with that process you did nothing wrong! years ago thats how they did body work! used a torch process was called heat shrinking and also the torch was used for lead fill till it was replaced with light weight filler resins! the metal on your old bug was thicker like 22gage and the newer steels are 16or18 gage
and i still remember all this from college!
thanks Duane

rallydiesel · « **Reply #7 on:** January 01, 2008, 08:17:46 pm »

So is this something you could do with home welding set-up like you would find at Canadian Tire/Princess Auto, etc?

Zulfiqar · « **Reply #8 on:** January 03, 2008, 10:17:16 am »

isnt sheet gauge size a decreasing thing, like 22 gauge is thinner than 16.

anyway - never torch weld the body or chassis, you end up with a soft spot,

blkboostedtruck · « **Reply #9 on:** January 03, 2008, 01:55:38 pm »

Quote from: "rallydiesel"

So is this something you could do with home welding set-up like you would find at Canadian Tire/Princess Auto, etc?

i'm not certain what canadian tire has? cause i live in the states someone should chim in that knows?

and Zulfigar correct me if i'm wrong it's been a while since i worked with gage sizes? i can be dislexic some times i'm sure you know what i mean?
older is thicker and newer is thinner!
thanks Duane

clbanman · « **Reply #10 on:** January 03, 2008, 02:16:06 pm »

Gauge sizes:
http://www.engineersedge.com/gauge.htm

I read in a hot rod type mag years ago not to weld the seams on a factory stitch welded chassis because the factory had designed the weld locations for the stresses the chassis would see, and if you welded the seams, you could move the stresses to areas that were not designed for them - leading to failure. No proof or background was given. My personal opinion is that most factory welding is done as stitch welding primarily to reduce cost, not because someone took the time to move weld locations around in a simulator program to find the ideal location. As mentioned previously, most failed welds have much more to do with the welder's technique and expertise.

One multiprocess machine:
http://www.millerwelds.com/products/multiprocess/shopmate_dx/

This one can't do MIG, but sweet size:
http://www.millerwelds.com/products/tig/maxstar_150_sth/

blkboostedtruck · « **Reply #11 on:** January 03, 2008, 02:31:56 pm »

ooohh they have gone down the last time i looked was a couple years ago they were in the 3,500.00 starting range for a multy process! sweet!
that chart clairifys my dislexic butt!! thanks
thanks Duane

blkboostedtruck · « **Reply #12 on:** January 03, 2008, 07:26:29 pm »

Quote from: "clbanman"

This one can't do MIG, but sweet size:
http://www.millerwelds.com/products/tig/maxstar_150_sth/

ahhh i got a welder in the garage simular to to one above and i never realized it could do TIG! all i need are the attachments! SWEET!! im in buisness now! i've been wanting to weld aluminum!
thanks Duane

Zulfiqar · « **Reply #13 on:** January 04, 2008, 03:00:44 am »

truck - yeah older were thicker,

Me and a couple of my mates are taking welding classes from this real old timer, we've all chipped into buying a used mig welder, All the welders here use the old oxyacytylene torch and wire,

this old geezer used to be head welder in Pakistan Steel, so he knows his business like no-one else,

I would end up with my yard n garage looking like a workshop.

QuickTD · « **Reply #14 on:** January 04, 2008, 07:58:38 am »

Quote from: "blkboostedtruck"

ahhh i got a welder in the garage simular to to one above and i never realized it could do TIG! all i need are the attachments! SWEET!! im in buisness now! i've been wanting to weld aluminum!
thanks Duane

Those little inverter welders are usually DC only, so TIG welding of aluminum isn't possible, steel/stainless only. For aluminum you'll need an AC power supply and a high frequency unit.