TIG Vs MIG on car chassis

[TarkMalbot]

When I first tried welding I found TIG much easier and neater than MIG but when I read anything to do with car chassis repairs MIG always seems to top the searches and seems the method of choice. What is the reason behind this?

Thanks,
Mark.

 

[Ragnarok]

mig will tolerate a bit more dirt than tig, and you don't need a long filler rod which there isn't always room for or isn't always easy to use under cars ect, plus mig is much cheaper to buy and to run, argon used for tig welding is about twice as expensive as the mixed gasses for mig, and you use more gas with tig as well, so much more expensive over all.

 

[zst]

There are two questiona more:
- Will arc ignition by HF at TIG destroy the electronic circuit in cars? There is an unconfirmed rumour that waves above 15000 Hz make ultrasonic welding in some car electronic circuits, and it is also the reason for avoiding TIG at cars... Is it true?
- It seems there will be more and more car bodies made of aluminium... As far as I know, most of them are made of al. 6xxx serie and are repairable, but there is a news that new Jaguars would be made of certain aluminium tri-plate or some sandwich foils... Any information about this?

 

[omkar]

hello. im new to this site so forgive me if im intruding on your discussion. i want to teach myself welding so i can restore my car but i dont know if i should learn mig or tig, but i have a question.

are there strength differences between tig and mig welding. seeing as a chassis is an integral part of a car, will the mig weld give the best strength weld or tig?
(of course this depends on the welders skill level, but that aside).

 

[outofthefire]

There are two questiona more:
- Will arc ignition by HF at TIG destroy the electronic circuit in cars? There is an unconfirmed rumour that waves above 15000 Hz make ultrasonic welding in some car electronic circuits, and it is also the reason for avoiding TIG at cars... Is it true?
- It seems there will be more and more car bodies made of aluminium... As far as I know, most of them are made of al. 6xxx serie and are repairable, but there is a news that new Jaguars would be made of certain aluminium tri-plate or some sandwich foils... Any information about this?

At work we connect surge protectors to the wagons batteries before any welding is done with mig or tig (although we rarely use tig, unless its a repair to an ally body), even so parts occasionally get damaged, the last was a starter motor. Also some makes of wagon cant be jump started because the surge can damage electronics, so I imagine modern cars would be the same if not worse.

 

[Tiggy_dorset]

There are two questiona more:
- Will arc ignition by HF at TIG destroy the electronic circuit in cars? There is an unconfirmed rumour that waves above 15000 Hz make ultrasonic welding in some car electronic circuits, and it is also the reason for avoiding TIG at cars... Is it true?
- It seems there will be more and more car bodies made of aluminium... As far as I know, most of them are made of al. 6xxx serie and are repairable, but there is a news that new Jaguars would be made of certain aluminium tri-plate or some sandwich foils... Any information about this?

I have asked this similar question myself, before now. From what I understand Mig can affect electronics as well as Tig. As long as you have a good earth lead connected as close to the job being welded as possible, there should be no problem as the current will always find the easiest route to earth. As long as there are no electronics in that path you should be ok. Also be careful of bearings as well as there is the possibility of arcs occuring within the bearings which willl pit them and obviously ruin the bearings. Damage to electronics is still possible but you lessen the chances with how I described above.

This is how I currently understand it so dont take it at face value.. I would be most pleased if I am to be corrected by the more experienced and technical guys here as it still is a question I have not had a complete guaranteed answer for I feel.

 

[mike os]

I was always told to disconect battery, altenator & ecu..... and do it out of habit...not that i do much car work these days.

 

[Tigman]

I was told to disconnect the battery too always have , never tigged a car but plenty of mig never had any issues with electronics ! but most of the motors Ive welded are old and not much in the way of electronics , not like up to date models !

 

[outofthefire]

I was always told to disconnect the battery as well, but it doesn't isolate the rest of the vehicles electronics if they use the chassis as the earth, thats why we use surge protectors. It would be really impractical to disconnect everything compared to the cost of repairs if you damage something these surge protectors aren't bad value for money http://cgi.ebay.co.uk/12v-Surge-Pro...aultDomain_3&hash=item19bf784166#ht_500wt_922

 

[Tigman]

So you connect that where ? for those of us who know little about electronics ( thats me ) oh I get it across the battery , sorry ! thickhead !

Nice idea!

 

[zst]

Well, I am trying to find the answer about TIG HF emission... No matter if the ground clamp is very close to the place of welding or not, I am said that HF could generate damaging radio-waves and create "ultrasonic welding" of tiny parts in electronic circuits and make a mess of them... So I am advised to ignite the TIG arc by "lift" techinque at cars, never by HF, or someone must change the frequency of HF at machine bellow some critical value...

I am just said like that, so I am interested if someone could confirm or reject this statement...

 

[shenion]

Yes the HF can damage the ECU. It can be picked up by sensor leads and fed to the ECU.

HF boxes float around the net as "PC EMP killers"

Lift start will be better. Always connect the ground lead to the same metal as you are welding.