Is tig stronger than mig?

[Gerry450]

I've been doing some research on welders and MIG welding for a few days, and a video got me onto TIG welding, which in turn brought me here. Ahh the wonders of the internet..

Anyway, I am in the process of restoring a TVR Chimaera and the task at hand at the moment is replacing the rotted outriggers. The OE tube that is used is 38mm OD 16 gauge mild steel. With some 3mm mild steel plates in the corners. I was assuming MIG was the way to go for this particular job, but now I'm not so sure.

My question after that intro is this: Is TIG welding going to produce a stronger and more applicable weld on this chassis (picture in my profile) than a MIG weld?
Bear in mind that a fiberglass body sits on this chassis, which may or may not have a certain amount of flex in it (an assumption as no testing has ever been carried out. But I do know that fibreglass flexes)

Any good advice greatly appreciated.
Gerry

 

[normspanners]

I bet the standard car was mig'ed
I looked at some production steering arms that had been tig'ed, they came off a westfield they looked beautiful-------- but broke on a track day test day ---- they where cleaned vee'd and mig'ed and are still on it now.

 

[doubleboost]

I think it is a case of "horses for courses" depends on the particular job
Try tig welding a paper thin / rusty exhaust
A coded tig welder would have problems on real thin rusty stuff
Some of the mig on motorcycle frames is shocking
Most of the tig on alloy frames is a feature

 

[Gerry450]

I bet the standard car was mig'ed
I looked at some production steering arms that had been tig'ed, they came off a westfield they looked beautiful-------- but broke on a track day test day ---- they where cleaned vee'd and mig'ed and are still on it now.

I believe so Norm.

 

[Gerry450]

I think it is a case of "horses for courses" depends on the particular job

The particular job is renewing the outriggers on this chassis:

The grey primer marks are where the cuts will be made. This is where the steel is good from there on, to the main chassis box sections. So NO welding rusted metal anywhere. Any rust you can see will be surface, which will be media blasted off after the welding is complete. Then hot zinc sprayed.

Here is a closer picture of one of the sections to give you a better idea:

The tube is 38mm OD 16 gauge mild steel tube. The triangular plates in most corners are 3mm mild steel plate.

 

[premmington]

MIG vs TIG...

Depends on metal wire quality and machine settings and operator training.

I MIG thin rusty steel...

TIG anything that must not leak...

MMA arc weld anything that must not break...


For production welding, laying lots of metal down, when you get everything right MIG takes some beating!

Out of the above three processes I mostly MMA weld stuff now.

 

[Kent]

had a conversation with a time served tig welder tonight and to be honest he peed me off a bit

reckons you cannot be coded in mig because it is a substandard method of welding and that tig is far stronger method of joining 2 pieces of metal and mig is just for muppets who cannot manage tig!!!!

Rubbish, codes exist in all even flame gas welding codes exist for pipe! All ways have their uses and correctly done all should create a stronger join than the parent metal. Its ever so slightly indicative of an uneducated one trick pony to make such a comment unless he is just teasing you. Time served TIG welder? when did a guy become time served only having trained using TIG? Am I just out of touch? Because I had to do it all plus a lot of other stuff besides. Is it this new modern apprentice thing?

 

[norlander]

My question after that intro is this: Is TIG welding going to produce a stronger and more applicable weld on this chassis (picture in my profile) than a MIG weld?
Bear in mind that a fiberglass body sits on this chassis, which may or may not have a certain amount of flex in it (an assumption as no testing has ever been carried out. But I do know that fibreglass flexes)

I'm a hobby TIG n MIG welder so bear that in mind, I reckon:

if you have a decent MIG set with a proper gas (not pub CO2) you should get sound welds on that chassis with proper preparation.

TIG is more precise, and can produce neater welds, and there is more control in the actual welding of the joint-but at my skill level I would not attempt that job, because I am slow due to being a part timer-I know that because of that I put too much heat into some jobs, so anything critical that needed TIG or where TIG was preferred, I would get a pro to do it, I would be more confident in my MIG skill level to weld up a chassis.

Looks like those original welds were MIG???

 

[wyn]

I'd be looking to replace the whole length of each tube, not just cut and add a bit on.

If you do join it like that slide some tubing up the centre and plug weld it as well.

 

[Gavin_d]

I'm coded in mig so he is wrong. Try a vertical up pass getting good penetration and no undercut and a half decent looking weld. It's harder than people think. Each process has it place. I think true down and dirty welding is SMAW. Can't beat it.

 

[Jim Davey]

Nothing wrong with a weld done with CO2, all MIG was done that way until they got clever with Argon/CO2 mixes.

 

[Turbo]

IMHO each form of welding is as strong as the other when properly done.
The problem with mig is that if a weld is not good internally ie poor penetration it can still look good on the surface and the welder can be fooled into thinking that they've produced a perfect weld.
If MMA is not done correctly it shows on the surface and it's probably the hardest one to master.
I find tig welding the easiest, everything you do is shown on the surface so you know where you go wrong. You can control the weld pool better and only add in filler rod as you need to. In the other 2 processes you have no choice, the filler rod is added whether you want it or not.

 

[Gerry450]

Thank you for all the replies gentlemen. On the balance of things, it seems MIG is the way forward. Regarding the tube, I am going to internally and externally sleeve the cut and joined parts. Just need to watch a few tutorials on plug welding.

What is a Cebora Stag 196 like compared to a Clarke or Sealey nowadays?
A guy told me yesterday that I'd be better off spending the same amount that would buy a new Sealey Supermig 180, on an older used better name MIG.
Hence the Cebora question..

Thanks again

 

[PhillipM]

From what is the normal quality of welding on those TVR chassis, I reckon some tie wraps and filler will probably match it.

 

[Kent]

From what is the normal quality of welding on those TVR chassis, I reckon some tie wraps and filler will probably match it.

Heck yes! The cars were built terrible

 

[Gerry450]

From what is the normal quality of welding on those TVR chassis, I reckon some tie wraps and filler will probably match it.

Very funny... :/

The problem with TVR chassis, is that the 1st few years of building Chimaeras' and other models of that era, TVR outsourced the chassis coating. These were the silver coloured chassis, which are still going strong today.
Unfortunately some idiot in an office with a calculator at the factory thought it would be a good idea to do it all 'in house'. That's where the problem started. They would leave chassis outside after making them, open to the elements. They never hot zinc sprayed them, so rust and rot is inevitable. Then powder coated them white. These were the white chassis, that are now suffering today. Slowly but surely people are now getting the problem rectified.

Anyway, back on topic.... The Cebora Stag 196? Anyone know how good they are compared to todays Sealeys, Clarkes, etc?

 

[Kent]

just out of interest, the TVR family are near neighbours of mine. I think I know the reason why these things had so many basic manufacturing faults and it comes with the queens head on it for a clue

 

[Monkey Harris]

just out of interest, the TVR family are near neighbours of mine. I think I know the reason why these things had so many basic manufacturing faults and it comes with the queens head on it for a clue

The queens head pub...

 

[Jim Davey]

Old Ceboras are good, not great but good. How old is it and what sort of money is it up for?

 

[norlander]

Nothing wrong with a weld done with CO2, all MIG was done that way until they got clever with Argon/CO2 mixes.

the pub gas I tried did not float my boat-I think the welds were probably sound-but the argon mix I have seems loads nicer and seems to work out cheaper-but this is France of course