I want to weld a 10 pt. cage in my car, what would be the best way to do it (MIG,TIG,stick,etc..)? Also, how would I go about testing some scrap pipe after I weld it? Want to make sure I can do it well before zapping anything worth keeping.

 

stick (SMAW) would be out of the question, mig (GMAW) or tig (GTAW) would work, my pick would be tig for the tube to tube connections and mig for the floor plates. you'd not want pipe but rather tubing with sometihng like a .187 wall. check a rule book for the exact size requirements.

 

Yeah, stick (arc) welding will melt your car; it's too "powerful". Instead of welding together, you'll be cutting things apart! If you go with MIG, make sure it's GMAW (gas) and not FCAW (flux core sheilded wire). FCAW requires more current and isn't good for thin sheetmetal (kinda like arc welding).

Practicing on regular sheetmetal should be fine. If you want a good book, dig up the Haynes Welding Manual (got mine from Lowe's Home Improvements for $15). It covers all the welding types, and how to use the equipment once you buy it.

One of those auto-darkening helmets will make life much easier for you, too. Mine is a Hornell Speedglass helmet, the "Utility" (non-adjustable) version. Looks kinda funky.

 

all the welding i'll be doing is with gas, either argon or helium, i have one of those auto-darkening helmets at work too, i love that thing for mounting the floor plates i'm guessing that a bead all the way around and a few spot welds around the middle should keep it in place right?
also i noticed the chrome moly tubing isn't that much more money then the mild steel, is it much harder to weld? (going to buy the cage from spohn)
and the last thing i was woundering about right now.. how would i go about testing my welds on the tube? i'm used to TIGing 316L stainless steel, and want to make sure i can get good welds on scrap tube before starting the cage

 

go to a local metal supply shop or any welding shop and ask if they have any metal tubbing that there goin to throw away and they should be bale to give it to you or give it to u for a small price. but for chromoly i would have no clue where you could get that, most places use mildsteel.

 

getting the stuff in no problem, but how do you test it? i've heard they x-ray the welds somtimes.. are there any other ways?

 

theres something called a dye penatrent test. ud probably have to go to a welding supply place (not homedepot or lowes) and ask them for a dye penatrent test kit. it 2 spary cans. 1 you spary on and after it drys u spray the second can on and then i think u wait 5mins and then u should be able to see if theres any cracks in the welds. but aving it x-rayed doesnt get used alot enless its something welded like the cooling towers of a nucler power plant or something that will be holding pressure, etc.

for a cage you dont need to have it x-ray quality, it doesnt hurt to have it that good but still, u dont need to go thru the trouble of welding in the cage and then finding someone that would do it. basiclly make sure u practice on some scrap metal gettin ur heat controls set to were it works nicely with the metal your using and afterthat go to town welding.

 

to test weld you can use x ray, dye, mag particle, ultra sonic. if you aren't sure you can make a good weld i wouldn't even try. you can do destructive testing on a representive sample of the parts. CM is hard to work, subseptable to HAZ cracking, hydrogn enbrittlement, and hot cracking. unless you know what you're doing stay away from CM.

 

If welding with a MIG the welder must be a minimum of a 145 amp unit, TIG around the joints would look much nicer without a doubt if you can weld with it. I think argon might burn a little to deep for welding to the floor pans. Also from experience, when welding the plates to the pan, turn the sensitvity way up on the auto lens as the floor usually has some imperfections that will flutter the bead causing the lens to turn off and on in quick sucsession resulting in that damn white spot where ever you look As far as tubing thickness, mild steel is minimum .134. Chrome moly? as I'm fixin to hit the sack or I'd look it up in my rule book for IHRA, it might be different if it's NHRA so you'll have to know what sanction your running more and conform to them.

 

We're making my cage with mild steel. Using a gas MIG welder and the old school non adjusting goggles. 1 and 3/4th's inches thick (this is for roadracing so NHRA rules dont matter to us anyway). We bought the hoop and a tube notcher from a company that sells stock car parts. We will be getting the rest of the material here locally. Should be around $150 for everything (not including the tube notcher, another $99 but a good buy for later use). We're building a chassis cage, so a 12 pt stock car style cage on the interior (will gut out the doors and all), but we will also be extending through the firewall into the engine bay. The chassis cage will extend from the radiator support to the trunk. Building the car to handle impacts. Stock car style....