Seam Welding

[welshpug 1,677]

have a look on the welding forum and you'll see quite a few mods you can do to the SIP's

[Baz 421]

Mig is a stronger weld than gas + the fact gas is harder to do.

 

The former isn't true, but is often the case due to the latter.

[SurGie 54]

Im sure if both have penetrated through enough im sure both are just as strong enough for car work, cant see anyone really wanting to use gas on car bodywork when mig is plenty enough ?

 

Iv had a few go's with gas in 2001 when i did a night course in car body work and found gas really easy. I did some good welds for my first ever go, the lecturer was impressed. I found getting the right flame is the key as well as timing.

[Mad Scientist 106]

I was told by a reliable source who used to prep the gp A 205s that they did very little seam welding. They did do the subframe though, and replaced the round tube on the subframe with solid bar.

 

Mind you, we are talking about a baggy 20 year old shell now, not a brand spanker.

[stu8v 68 1 Cars]

Can i just add my two pence with the cheap migs i have a sip one and its crap tbh.I know you say about the settiings cam but theres only 2 to choose from so its quite hard ,Ive managed to spot weld with it but thats about it ,My cheap sip seam to feed the wire in phases like if you hold the trigger it will give you say a two second burst then cut out for a second then back on really akward to use.

 

Why does nobody gas weld shells cages etc?.Every one seems to either mig or tig

 

I know of an Escort Cosworth built to the last of the line Grp A regs with a brazed in cage.

 

Most cant gas weld TBH although its not that hard.

[Liquid_106 97 1 Cars]

Iv had a few go's with gas in 2001 when i did a night course in car body work and found gas really easy.

I know it's a while back, but where and how much, if you can remember.

 

cheers

[SurGie 54]

Leicester college near Sainsburys, it was around the £100mark but not certain as it was ten years ago. They have changed it all now and have their workshop at the other side of the campus. I dont think they do night bodywork anymore with the cuts and all but its worth giving them a bell as you never know.

[Cameron 16]

The former isn't true, but is often the case due to the latter.

 

It all depends on whether it's been done properly, but MIG generally gets a fatter weld bead so I'd say it would be stronger in some situations like fillets.

[Liquid_106 97 1 Cars]

Leicester college near Sainsburys, it was around the £100mark but not certain as it was ten years ago. They have changed it all now and have their workshop at the other side of the campus. I dont think they do night bodywork anymore with the cuts and all but its worth giving them a bell as you never know.

Cheerd SurGe, think I've looked there already but I'll check

[brumster 135 1 Cars]

I use a budget Clarke MIG bought years ago from machine mart and I must admit, it's done me proud and I'm quite used to it now. Sure, I'd love a bigger, fancier one but it doesn't get enough use to warrant it. One thing I will say, though, when I moved up from the little hobby gas cylinders to a proper half-size Argoshield bottle, s*it me, did it make a difference. Wish I'd done it years ago! So I guess gas can make one hell of a difference? Otherwise I agree that learning what settings work for certain thicknesses of steel helps, but that's just experience...

[harryskid 193]

Gas welding done correctly is very strong and when i use to pipe weld with gas first was a root weld and then a cap weld over the top. Problem is the large amount of heat and on sheet metal you could find heat distortion, where on mig is best for cars. Thicker metal i would rather arc weld, but thats what i'am use to.

[hcmini1989 16]

Gas welding done correctly is very strong and when i use to pipe weld with gas first was a root weld and then a cap weld over the top. Problem is the large amount of heat and on sheet metal you could find heat distortion, where on mig is best for cars. Thicker metal i would rather arc weld, but thats what i'am use to.

Can i just add one thing ,The henrob torch isnt a conventional torch you could weld tin foil with it if you wanted .And i was speaking to my bosses dad who happend to work at fords building shells in the 70s and 80s and he reckons most of the rally ones were just brazed and reckons they are pretty strong. And ive yet to use the gas welder yet but hopefully ill get some spare time to play with it,The only reason i bought it was so that i dont have to buy another mig and then a tig for ally .But it does apear to be abit of a black art as not many people do it ,

 

Ive always thought it would be better to melt the two peices of metal together without adding anything to it such as mig wire etc,Im no welder or anything but wouldnt this be stronger?. And yes i know this would distort the metal abit due to the heat generated when melting the two together.

Edited February 18, 2011 by hcmini1989

[Cameron 16]

This is how F1 manifolds are welded up, they just TIG all the butt welds with no filler wire. You can also do it for external fillet welds (i.e. the outside of a corner) BUT it isn't stronger than adding filler, think about it, adding material will always make something stronger. Plus, if you've ever tried TIG welding you'll know that if you don't add enough filler to certain kinds of weld you get undercuts (where the metal melts and thins the material) which are weak points.

Edited February 18, 2011 by Cameron

[Rippthrough 98]

Not in most cases hcmini, you change the physical properties of the metal when you create a weld pool to melt it together, the filler is used to both modify those properties back to what you want, and to create a thicker area or fillet between them to reduce stress.

 

There are specialised area's where that is the case, but boy do you need some equipment to make it work how you want to:

 

 

 

 

FWIW, a perfectly brazed joint is usually stronger than a perfectly welded one. The problem is the difficulting in achieving the former vs the latter...

Edited February 18, 2011 by Rippthrough

[hcmini1989 16]

Not in most cases hcmini, you change the physical properties of the metal when you create a weld pool to melt it together, the filler is used to both modify those properties back to what you want, and to create a thicker area or fillet between them to reduce stress.

 

There are specialised area's where that is the case, but boy do you need some equipment to make it work how you want to:

 

 

 

 

FWIW, a perfectly brazed joint is usually stronger than a perfectly welded one. The problem is the difficulting in achieving the former vs the latter...

Im really impressed ripthrough , I was strugaling to grasp how they were working on the 1st and 2nd vid but the 3rd one made it all clear and that is fancy.And cheers for the pointers cam ,Ill invest in some rods

 

EDIT-Sorry for the hijack

Edited February 18, 2011 by hcmini1989

[Rippthrough 98]

In the first two they're running less heat - just hot enough to get the material so it's almost like plastecine - the tool itself 'stirs' the metal together.

 

Like mixing epoxy or bodyfiller up.

Edited February 18, 2011 by Rippthrough

[hcmini1989 16]

In the first two they're running less heat - just hot enough to get the material so it's almost like plastecine - the tool itself 'stirs' the metal together.

 

Like mixing epoxy or bodyfiller up.

Surely this has to be the stongest type of welding you can do?.Its essentialy making it so there isnt a join there.

[rallysteve 22]

I did a metalwork course with a company who hand form classic jaguar body panels/shells and all of there welding is done by TIG welding the pieces together with no filler as it means there is no extra material added to cause problems with smoothing the panel. Pretty amazing results, and really not that hard to do as long as you have perfectly parallel panels with no gap between.

 

Steve

[Cameron 16]

I'm not so sure, I think the reason they do the stir welding is because of the thickness of the metal they're joining there and the difficulty in getting full penetration (oo-err). I don't know if it would be stronger than a conventional weld on thinner material, I kinda get the impression it forms some funny grain structures that can't be quite as strong as those formed from a proper weld pool.

 

The friction welding of cylindrical stuff is brilliant (3rd video), some pretty incredible forces there to generate that much heat!

[Rippthrough 98]

Best thing about stir welding is it lets you weld materials that are normally incompatible due to melting temperature differences/sheild/puddle incompatibility, aluminium can be welded to steel or copper for example.

[Cameron 16]

Cool.

 

It's also possible to weld different materials with the rotational friction welding, isn't it? I remember watching videos about it at college.

[harryskid 193]

Any one tried to weld cast iron thats a bugger, i never got that right eve at tec!

[hcmini1989 16]

Any one tried to weld cast iron thats a bugger, i never got that right eve at tec!

Welding it with what mig tig etc.If you youtube henrob 200 theres a vid on there of someone welding a cast iron maifold with a crack in it,He uses the henrob torch and an old piston ring to fill the crack and does the job ,How easy it is i dont know ive read alot on this and it seems quite hard just the guy on the vid is an expert on it

[omega 82]

so anyone got any pics of a seam welded subframe?

[SurGie 54]

Yeah me too.

 

Is it a good idea to fully seam weld the sub frame or stitch ? I assume fully seam weld.