Infact you can use an oxy torch to add carbon to steel. It is called carbonizing and is usually used for hard facing.
What Gauge metal to use
Started by
_OZZ80Y_
, Jun 29 2010 08:50 PM
32 replies to this topic
#26
TerrA LX
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Posted 24 January 2011 - 10:46 PM
#27
_Quagmire_
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Posted 24 January 2011 - 10:56 PM
Oxy welding (or brazing) is your worst enemy on sheet steel car panels. Any form of flame welding burns the carbon from the steel leaving it as tin. Once the carbon is gone tin will rust at an extremely aggressive rate if it cannot be properly prepped and sealed on Both sides. TIG is not as bad as oxy, However if you can master the mig with .6mm wire you will get great results. After many years of experience I can butt weld panel steel with the mig using .6 wire in continuous runs...... I choose to do this to eliminate the overlap joint that holds moisture and assists the start of new rust. Practice with different settings, keep it clean and free of paint/zinc/gal etc and you will soon be getting satisfactory results.
heat shrinking is still used on some cars
so does this affect the make up of the panel and render it rust prone?
#28
S pack
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Posted 25 January 2011 - 01:26 AM
Oxy welding (or brazing) is your worst enemy on sheet steel car panels. Any form of flame welding burns the carbon from the steel leaving it as tin. Once the carbon is gone tin will rust at an extremely aggressive rate if it cannot be properly prepped and sealed on Both sides. TIG is not as bad as oxy, However if you can master the mig with .6mm wire you will get great results. After many years of experience I can butt weld panel steel with the mig using .6 wire in continuous runs...... I choose to do this to eliminate the overlap joint that holds moisture and assists the start of new rust. Practice with different settings, keep it clean and free of paint/zinc/gal etc and you will soon be getting satisfactory results.
This is dribble.
Oxy is the best if you are good at it.
Which I,unfortunately am not.
It is a dying craft which most metalworkers and panelbeaters no longer use due the time restraints and the skill and training involved.
Panelsteel composition has also changed,which renders it useless on modern vehicles.
Hammer welding with an oxy gives fantastic results on butt welds with very little grinding necessary. Great esp for large open panel joins with no distortion once you get the hang of it.
There are lots of components that make up the modern motor vehicle body that are made from a variety of High Strength Steels that should not be heated or welded otherwise the strength of the component will be reduced and in some cases may actually render the vehicle non compliant with the ADR's.
Some of these steels are also hard to weld because of their alloy content.
But don't worry you won't encounter body components made of HSS on pre 1979 cars.
Edited by S pack, 25 January 2011 - 01:27 AM.
#29
_Yella SLuR_
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Posted 25 January 2011 - 05:02 PM
Oooh, ahhh, that threw the cat among the pigeons didn't it.
You normally learn on oxy to understand how metal distorts with heat (principally the wheel chock exercise, you learn how to tack and control distortion). The oxy process is fairly slow, so you get to see the weld pool, etc. It all happens a bit faster with MIG, but still the same issues: pulling, and heat distortion.
Personally, I like oxy welding, and not a prob when you know what you are doing. Heat shrinks are ace (they also show you how to do those in the resto course, and there are a few of them in the pic ^^).
I haven't tried 0.6mm MIG wire, might give that a go, I've only ever used 0.9mm on panel steel, but it's a pretty good MIG. Might give that a go.
You normally learn on oxy to understand how metal distorts with heat (principally the wheel chock exercise, you learn how to tack and control distortion). The oxy process is fairly slow, so you get to see the weld pool, etc. It all happens a bit faster with MIG, but still the same issues: pulling, and heat distortion.
Personally, I like oxy welding, and not a prob when you know what you are doing. Heat shrinks are ace (they also show you how to do those in the resto course, and there are a few of them in the pic ^^).
I haven't tried 0.6mm MIG wire, might give that a go, I've only ever used 0.9mm on panel steel, but it's a pretty good MIG. Might give that a go.
Edited by Yella SLuR, 25 January 2011 - 05:03 PM.
#30
_TorYoda_
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Posted 25 January 2011 - 07:43 PM
Oxy welding (or brazing) is your worst enemy on sheet steel car panels. Any form of flame welding burns the carbon from the steel leaving it as tin. Once the carbon is gone tin will rust at an extremely aggressive rate if it cannot be properly prepped and sealed on Both sides. TIG is not as bad as oxy, However if you can master the mig with .6mm wire you will get great results. After many years of experience I can butt weld panel steel with the mig using .6 wire in continuous runs...... I choose to do this to eliminate the overlap joint that holds moisture and assists the start of new rust. Practice with different settings, keep it clean and free of paint/zinc/gal etc and you will soon be getting satisfactory results.
This is dribble.
Oxy is the best if you are good at it.
Which I,unfortunately am not.
It is a dying craft which most metalworkers and panelbeaters no longer use due the time restraints and the skill and training involved.
Panelsteel composition has also changed,which renders it useless on modern vehicles.
Extensive experience forces me disagree with you Wot. I can Oxy as skillfully as I can Tig and I Mig better tham most.
Mig weld a piece of bare panel steel and chuck it out in the yard. Oxy weld a piece of the same material and place it next to it. Check them both in a month or two and see which one is more severely rusted. It will be the flame welded piece! Stress test both pieces before you toss them out in the weather.... you will find the flame welded piece has less tensile strength than the Mig welded piece. Any form of Flame welding that produces a molten pool burns the carbon from the steel in the HAZ. (heat affected zone) It is not possible to reintroduce the carbon properties of the welded steel in situation so for this discussion my facts are indeed correct. Low carbon steels were referred to as tin when I was learning the trade. (I realise pure tin is a different material altogether, yes) Tin is a softer, more malleable material than steel. A flame welded repair section loses its tensile properties much worse than Mig or Tig because the heat affected zone is much larger and more extremely affected. This is a scientific truth.
Do the test and prove it to yourself. Cheers.
Modern 'panelsteel' is little more than mild tin these days which is why it doesn't last and is so soft and easy to shape. Good sheet steel is still available but is costly and difficult to find for sale in small quantities.
Edited by TorYoda, 25 January 2011 - 07:47 PM.
#31
_TorYoda_
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Posted 25 January 2011 - 08:00 PM
Oxy welding (or brazing) is your worst enemy on sheet steel car panels. Any form of flame welding burns the carbon from the steel leaving it as tin. Once the carbon is gone tin will rust at an extremely aggressive rate if it cannot be properly prepped and sealed on Both sides. TIG is not as bad as oxy, However if you can master the mig with .6mm wire you will get great results. After many years of experience I can butt weld panel steel with the mig using .6 wire in continuous runs...... I choose to do this to eliminate the overlap joint that holds moisture and assists the start of new rust. Practice with different settings, keep it clean and free of paint/zinc/gal etc and you will soon be getting satisfactory results.
heat shrinking is still used on some cars
so does this affect the make up of the panel and render it rust prone?
If the heated section is not properly sealed on both sides it surely does! Not all areas we repair on cars can be accessed to effectively prepare and seal on both sides and this is why I choose the least damaging method of welding the parent metal. When I need to shrink I cut the high section with a 1mm abrasive blade to allow it to relax and run a mig weld down the cut. Immediate results with minimal impact on the surrounding material.
#32
TerrA LX
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Posted 25 January 2011 - 08:24 PM
Mig wire is high tensile, that's why it is harder to dolly a mig weld without cracking. Alloys in the wire are less prone to oxidising.
Oxy welding, as with cutting involves oxidising the metal, there is no hydrogen fusion or nuclear physics going on here, you just need to treat it as per bare metal.
Oxy welding, as with cutting involves oxidising the metal, there is no hydrogen fusion or nuclear physics going on here, you just need to treat it as per bare metal.
Edited by TerrA LX, 25 January 2011 - 08:32 PM.
#33
_Yella SLuR_
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Posted 25 January 2011 - 09:43 PM
Interesting. There's no doubt about it Toyoda, the heat zone from Oxy, even when controlled is larger.
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