MIG vs TIG welding for chassis

[rwolcott23]

Is there a clear advantage between MIG or TIG welding for chassis construction (steel tube space frame). We have always TIG welded, but it has been a 'learn and practice for a week, then build the chassis' sort of thing. Is a good MIG welding job better than a questionable TIG job? If there are significant differences between the two methods (strength etc...), what are they?

[rwolcott23]

Is there a clear advantage between MIG or TIG welding for chassis construction (steel tube space frame). We have always TIG welded, but it has been a 'learn and practice for a week, then build the chassis' sort of thing. Is a good MIG welding job better than a questionable TIG job? If there are significant differences between the two methods (strength etc...), what are they?

[IsheeM]

There has already been a lot of discussion about this. Try doing a search for the info.

[rwolcott23]

I ran several different searches and couldn't come up with anything.

[Charlie]

Something is wrong with the search function. Seems to only return todays posts

[leclercjs]

Ok, to clear that up, TIG welding (when you know the basics) is for me better than MIG welding since you actually melt the metal and melt the to part you are assembling (TIG welding is accredited for aerospace, not MIG). MIG welding can be tricky if you do not use the right amps and the right feed, you can easily make a ''cold'' weld and it resume having a very weak weld since you've not penetrated the metal you are bounding. TIG weld will assure you a strong welding and even save you grams if you know well to weld since you are not always adding metal to your structure. Also, a TIG job is much cleaner than a MIG job for my point of view. But, if you don't have the skills and the time of TIG welding, MIG welding is the easiest and can be comparable to a point of view to a TIG job.

Also, if you are using MIG welding, I would suggest you do a stress relief after you've finish welding your frame and brackets. It will help the frame get rid of the stress induce by the welding (also it helps on a TIG welded frame) and will make your structure uniform (near welding, you are making the region less ductile and more fragile if you let the welds to open air after welding).

Hope it helps

[Travis Garrison]

IMHO MIG has no place on a racecar. Big ugly welds typically with less penetration. I've even seen some very shady mig work where it was "flowed out" later to cover up what I'm assuming was next to no penetration, if I hadn't seen the whole process it wouldn't have been terribly obvious how bad the weld actually was, the point being exactly what Jean was getting at, with all the rod mig welds use it's not always obvious what the weld quality actually is.

If you are making a low budget car, using square tube and going for producability then its probably more than alright...but if you're using expensive alloy tubing and going to great lengths to shave weight elsewhere on the car a mig job would be a crime, kind of like using 5 minute epoxy to attach components to an elaborate composite monocoque chassis.

Take some pride in your work...keep using the tig. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Travis Garrison

[clausen]

Some opinions we've heard
- Our uni workshop fabbie who is a drag race scrutineer says tig should be used on alloy steels but Mig is better for plain carbon steels.
- One of the professors here that specialises in welding says we should use mig becuase of the higher heat input, and she thought its easier to do a reasonable Mig weld than a reasonable Tig weld, but a pro Tig weld will be better than a pro tig weld.
- A racecar fabbie that I work with says we should use Tig because of the lower heat input giving less distortion, and you can make lighter welds (I guess he deals with touring car roll cages that have about 80 tubes in them)

So in the end I think we are mig welding our plain carbon steel chassis.

[Gonzo]

To echo Carroll Smith's words, arc welding (read also mig welding) is fine for repairing the truck or trailer but has no place on a race car.

Mig welds are ugly, lack penetration, create a large heat affected zone and are full of porosity. Try welding a steel tank with the mig and then pressure testing it if you dont believe me about the porosity. I have used the mig twice this year, for making the chassis table and the welding screens.

Tig welding produces a far neater weld with less heat affected zone. Practice makes perfect so keep practising with the tig.

I dont believe anyone that says Mig is better than Tig for plain carbon steel unless you are in a real hurry.

Tig is not that difficult, pro welders just say it is so that people think they're special http://fsae.com/groupee_common/emoticons/icon_smile.gif.

[RagingGrandpa]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Gonzo:
Tig is not that difficult, pro welders just say it is so that people think they're special http://fsae.com/groupee_common/emoticons/icon_smile.gif. <HR></BLOCKQUOTE>
Hey now! SHHHHHHH

[MikeWaggoner at UW]

Doesn't anyone use google anymore? Good article:

http://www.ridgenet.net/~biesiade/weld.htm

[Gonzo]

Sorry RagingGrandpa did i just let the cat out of the bag? http://fsae.com/groupee_common/emoticons/icon_confused.gif

I keep telling my team how easy tig welding is but refuse to let them use the welder otherwise I might lose my job.

[Frank]

MIG for production, TIG for racecars

OXY of you are "old school" http://fsae.com/groupee_common/emoticons/icon_smile.gif

[The guru of guru's]

Ahh the old mig/tig debate...i think the mig should be parked next to the arc and left there! TIG is easy and can be learnt quickly with little effort. I suggest anyone who has a spare moment in the workshop use it on the tig instead of passing wind!!!
Cheers
Dave

[rotor]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Frank:
MIG for production, TIG for racecars

OXY of you are "old school" http://fsae.com/groupee_common/emoticons/icon_smile.gif <HR></BLOCKQUOTE>

i didnt notice any brazing on your car frank...

mark hester
rmit

[Frank]

i meant oxy welding http://fsae.com/groupee_common/emoticons/icon_wink.gif
(no i didn't do any oxy welding on the car, but it fascinates me when i see it done.. my old man was sweet at it)