MIG or TIG When Frame Building?

I actualy saw a guy take a cutting torch and "blow out" two broken off header studs/bolts without harming the threads in the head! I was blown away remembering all those I tried to drill out! Still not sure how he did it. I never tried it, anyone else seen this technique?

 

Another thing some people really need to pay attention too, is the rules that apply to a Fillet Weld. The fillet is a triangle & the leg's of the fillet weld always..ALWAYS...need to be equal too or greater than the base material thickness.

So, if your welding 3/8 plate together in a T shape, then the legs of the fillet weld need to be 3/8's or greater to certify.

Go ahead an start looking over all your TIG welded stuff, even the stuff from the stores and you will easily see, most people stop the puddle WAY before the legs of the fillet are equal too or greater than the base material thickness.

Yes...the TIG welds all look pretty and I'm not against TIG and do plenty of it, but just look some of them welds over & you'll easily see Most are way too small of a fillet compared to the base material thickness. Pretty ..yes, safe......you be the judge.

I'd go so far as to say, 90% of TIG welds I see don't even come close to having the leg's of the fillet match the base material. They can look great, but......pay some attention to it and you'll start to notice.

Also, alot of processes end up using both MIG & TIG for the same weldment, likewise TIG & ARC for the same weldment.

Shorten a sway bar.......cut, bevel, do multiple p*** of TIG in the center & then go back and filler all up with multi p*** of ARC. "I don't use any MIG in that one"

Look at some of the TIG pics' on this thread or others and you'll see how the fillet welds are not close to the base thickness. It's all a process and we do use our own methods, but some of these things have already been put into place by years of experience way before any of us.

Carl Hagan

 

I think you guys meant slide over the next size. Wall thickness doesn't matter when you're sliding inside...

 

tig is slow mig is fast arc is the best

 

Interesting point of view. I would say MIG is the best option for a home hobbiest (someone who doesn't get paid for their work). If you have a shop or are working on customer cars, I would expect that you would lean towards TIG.

 

Slightly OT,but after following this post, I remembered there was a guy in this neighborhood who used to braze his slingshot dragster frames together,guessing early sixties ,by the one I saw...he was highly proficient, and they looked real nice...but scary...! his nickname ,which was a parody of his real name, was "Brazelhan" or something like that...anyone remember him?

 

THANK YOU!!!
And the corollary to that is that many people will NOT listen to anyone who is not ***ociated with a shop or otherwise in the "industry".
Meaning some mouth-breathing schmuck whose brother-in-law managed to get him a job in a repair shop will be worshipped as a god on the subject; yet you, who have toiled for seeming centuries at the same thing, learned all you know from hard-fought experience, are given the same respect as a booger on a windshield.

Cosmo

 

There are a lot of valid points on this thread, and just as many opinions. The majority of the material used in a hot rod ch***is is 3/16" thickness or less, so pretty much any welding process can work just fine....just as long as the person behind the welder knows what they are doing.

I think one of the best things about the TIG process is that it doesn't let you "cheat" like you can with MIG. You have to have absolute cleanliness before you start welding, or it's going to bite you in the ***. With a MIG you can weld right over rust or other contaminates and keep on going...same for less than perfect gaps. With the TIG, you need to have the joint you're welding fit a lot more precisely.

All in all, TIG just adds up to a cleaner finished product in most cases. I want to have the absolute best finished product that I am able to produce, so I use the TIG....simple as that.


Thanks for the props JeffreyJames!

 

Thanks for the correction.

Da Tinman, you are correct, .058 is the correct wall thickness. My crusty old memory pulled up the .063 number. .005 can make a hellava difference from go to no go.

Guess I should stay out of welding threads, since I hav'nt fabbed a ch***is since the mid 80's, but I still do some tig welding on occasion, just no moly tubing. Hope no one goes out and buys a bunch of .063 wall moly to build a ch***is. They will sure be upset when they get home and start trying to fit it. Sorry for any confusion, guys and gals.

408 AA/D

 

Sorry B***, I know (I HOPE) you're not excusing the lack of metal prep. I gotta say no, No, and HELL NO! You CAN weld over that **** with a TIG as well, just like you can weld with dirty tungsten. You get the same results with MIG or TIG...a ****ty weld.

 

yeah they better have a big hammer!!

 

I prefer to use tig first when possible. One of the nice things about tig is that it puts almost no smoke in the air compared to mig or stick. Stick has its place too but is by far the worst for smoke. In a small home shop like mine it makes a difference and helps keep the wife happy!

 

Although I prefer TIG, I MIG welded many Off Road Race Car and Truck ch***is, chormoly tubing, for years. We would normalize the ch***is by utilizing a local heat treating company and never experienced weld or weld joint failures, nor was cracking near the weld a problem. We mainly did MIG to keep costs lower, there are a ton of tubes and welds in an off road ch***is!
Like any weld process, it's a matter of proper welding with proper filler material and absolute cleaning and prep.

 

Did you guys do any pre or post heat? I helped certify a process on 4130 last year, we were welding 3/8"dia. 1/16"wall tubing(both fillet and open groove). We did a bunch of sample pieces all different ways(no pre or post heat, one or the other, different temps, different filler metals[er80-d2 and er70s6]) and they ALL p***ed the destruction tests when sent to the lab. Some were more elastic, some were more brittle, but they all p***ed. Perhaps because of the small size of the tubing the heat treatment wasn't too much of an issue. This is a subject that a lot of people think they know the answer to, but few really do

I don't understand the needlepoint reference? Maybe if you're pulse welding sheet metal, but even then I don't think you want the background current to go below the point where it's not keeping a puddle. My tig welds are definitely one continuous bead!

I take pride in my workmanship whether I'm tig or mig welding. The question is which process is best suited for the application.

Definitely takes a nice touch! I would imagine you'd need to chase the threads at least afterwards, to get all the slag out? I've had to blow out bolts at work, but nothing that small.

That's definitely a good point on the fillet size. There are tolerances on going over and under though. You can't just put a half inch fillet on a 3/8" plate. Most people don't understand joint prep or design either. My "day job" is as a millwright/maintenance welder, and I always get guys or bosses that just want me to put a pretty bead over a crack. Or weld a 2" by 2" bar together by just laying a bead around the outside of it. They can't understand why I need to take the time to v the thing out to get 100% penetration.

Every situation is different. Some jobs it can be your preference, and a lot of times any of the processes will do. But usually one will be the BEST way, you just have to have the experience to know what it is!

-Josh

 

Back in the day used to do this a lot. I did field work on heavy earth moving equipment like Cats, Terex, Le Tourneau etc etc, to fix things all you had was tools, arc welder & gas axe. You needed to be creative, so cutting of nuts, cutting out studs was common place ... could I still do it The key is the stud will heat at a different rate than the surrounding metal, you punch a hole through the center of the stud, make sure the host metal (block, head etc) is cool & then you can cut without hurting the threads, steady hands good eyes helps.

 

kiwikev makes some of the tiggiest looking mig welds!
TP

 

I've got a question for all you Tig experts:

What size Tig machine would you need to work on ch***is stuff, say up to 1/4" thick mild steel max? Also, if you wanted to Tig weld aluminum do you need a way bigger machine since the aluminum conducts the heat away so fast?

Mig welding is what I've used for everything I've ever done. Tig's nice and pretty, but it's always seemed way out of my league price-wise. What would be the minimum size Tig machine that you could get away with for doing ch***is type stuff? Probably I'll never be able to justify buying a Tig machine, but it would be nice to know what the minimum size machine would be just in case I see a good deal on a used one someday.

Thanks.

 

Good question Rusty......I've been thinkin' of getting a TIG machine myself, but the price is $$$.
Anyone try the new Miller 165?
http://www.millerwelds.com/products/tig/diversion_165/

 

Nuclear reactors are TIG welded. Before they went to carbon fiber,
all the Formula 1 suspension parts were TIG welded.

NASCAR shops use MIG because it is quicker and easier.

Done properly, by any process, good welds are not brittle.

 

I always use backing plates inside the tube on all my seams when building frame rails, at least between the axle/spring mounting points. On those backing plates I put several rosette(plug) welds. So, I use mig on everything between the axles. For crossmembers, brackets, gussets, frame rail seams "outside" of the axles, and such, I would tig, if I had one available. That's my way of doing it.

 

I like JB Weld....

 

I'd be interested on feedback on that machine also...

 

I would be looking in the 250 amp range if you plan to do serious fabrication work. That ought to be adequate for aluminum too, unless you're doing some pretty thick material. One thing you'll definitely want if you're welding aluminum is a water cooled torch. Most of the small machines do not have them, although they can be added later. Inverters are nice because they are small and more portable, plus some can run on 110. But transformers are more durable and most people don't know how to use all the wiz-bang stuff on the inverters anyway. I looked at everything on the market a couple of years ago and ended up buying a Miller Syncrowave 250DX TiGRunner package, and it has been great. Never had a problem with any of my Miller equipment.

 

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</TD><TD cl***=alt1 id=td_post_3207728 style="BORDER-RIGHT: #e5e5e5 1px solid"><!-- icon and ***le --> Re: MIG or TIG When Frame Building?
<HR style="COLOR: #e5e5e5; BACKGROUND-COLOR: #e5e5e5" SIZE=1><!-- / icon and ***le --><!-- message -->Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD cl***=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Rex Schimmer
MIG (Mud gun) is for trailers and TIG is for race cars and hot rods!
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Are you trying to tel us what your MIG welds look like?
<!-- / message --><!-- sig -->__________________
"beep beep my ***..."

ZMAN,
I only have a TIG welder and do everything from 22 gage to 1/2 inch thick plate with it. Never had a need for a MIG (Mud gun) or even wanted one.

Rex
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If you are going to be doing any amount of aluminum, inverters are the way to go! I do a lot on both, we have a 350 Syncrowave at work and I've got a Dynasty 200dx at home. Obviously the 350 is the only way for thick(>1/4") aluminum, but anything else and I'd MUCH rather use the dynasty! Having the ability to fine tune the hertz and not have to use continous high frequency makes a huge difference. I do a fair amount of al with my Dynasty and I don't have a water cooler, but it's definitely in my future. I can't say much bad about the syncrowave, but I love my 45lb 200 amp dynasty that can run off 110/220/480! It's not cheap though, and it's not easy to find used. Syncrowaves pop up much more often on craigslist, ect.

I'd like to hear from someone with first hand experience with the diversion too. I don't think a guy making a living welding will want one, but it looks like a sweet machine for someone's garage. For under 1300 it looks like a good deal. Millerwelds.com has a pretty decent forum, I know there's some feedback on there by now.

-josh

 

I'm happy for you, but I'm still wondering about your mud gun comment. If that's what you're seeing then you need to get out more. Of course I've seen people do ****py stuff with all the welding processes.

 

I have a Miller Maxstar 200DX (as I really don't need aluminum capability as there is none on my cars except for engine castings . . . and I'll have somebody who does it for a living weld on those parts!).

The inverter machines are fantastic . . . the portability is a big deal for me. I can throw it in the trunk and take it to a friends house and weld up to 150 amps off of 110 volts. Or imagine you're headed to Bonneville and might need to "fix" something using the outlet at your hotel . . . inverters make all of that possible. Also, even in the shop, it is nice to have a light weight welding cart that can easily be moved around -- and I only need a 220V 35 amp line to handle it.

Cost is an issue - I bought the base unit new for about $1300 ( great deal ), but by the time you purchase a couple torches, gas bottle, foot control, dual gas meters and all the "stuff" that it takes for the full setup, you'll have another $1500 in it (without a water cooler). It all adds up, but if you're doing a lot of your own frame fabrication, it will pay for itself in a relatively short period of time.

I'm new to TIG, but I found the machine fairly easy to use . . . just practice a lot with it and it is amazing what you can produce with it - from 3/8" thick to 22 gauge . . .