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brightspark
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oxy acet welding is far smoother than mig and hardly needs anything grinding off it 
the metal is not softer it just doesn't leave lumps to grind off if u are proficient at gas welding
the metal is not softer it just doesn't leave lumps to grind off if u are proficient at gas welding
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WorkshopChris
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You can work and planish an oxy acetylene weld far easier than mig its the ideal process for rebuilding pannels where lots of forming and working are involved.
RonA
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I’ve read a lot of American restoration books were they advocate Oxy Acetylene welding because you can planish the weld while still hot to flatten it out & virtually avoid grinding altogether. They even show torch cradles so you can put the lit torch down & quickly grab a hammer/dolly to flatten the weld.
RonA
RonA
Fazerruss
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I've noticed mig is harder than tig when it comes to machining parts in the lathe. For example building up a worn area on a pulley or shaft.
I was told by an experienced welder this is due to mig wire being made of a harder composition to withstand being pushed from the machine to the torch.
I was told by an experienced welder this is due to mig wire being made of a harder composition to withstand being pushed from the machine to the torch.
WorkshopChris
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I have a gas economiser i fit in line if doing a lot of oxy welding, when you put the torch down flame goes out, then when you pick it up again you just light if from the pilot flame and off you go no re setting the torch. Well worth the cost in both gas and time saved.
Richard.
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Actually there is every chance a mild steel weld produced by OA or tig is going to be softer to grind than a mig weld.
It’s common with mig welds to be put in cold. This causes pretty immediate cooling rates and is known as a form of quenching.
This fast cooling or quenching can make the weld metal a substantial amount harder to grind or machine than the parent material.
OA you won’t get this. You completely heat the parent material in order to get a gas weld to flow. The cooling rate is way slower and this quenching doesn’t happen. The weld will be softer.
A hard weld isn’t a particularly good thing which is why mig shouldn’t be put in too cold. Along with lack of fusion defects this cold hard weld can become brittle particularly on higher carbon steels.
It’s common with mig welds to be put in cold. This causes pretty immediate cooling rates and is known as a form of quenching.
This fast cooling or quenching can make the weld metal a substantial amount harder to grind or machine than the parent material.
OA you won’t get this. You completely heat the parent material in order to get a gas weld to flow. The cooling rate is way slower and this quenching doesn’t happen. The weld will be softer.
A hard weld isn’t a particularly good thing which is why mig shouldn’t be put in too cold. Along with lack of fusion defects this cold hard weld can become brittle particularly on higher carbon steels.
Richard.
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Hardfacing cladding Processes are often done with high travel speeds to get the maximum hardness out of the consumable. Fast cooling/quenching rates really get the best results from a hardness point of view. It also helps to reduce dilution of the parent material too. A lot are welded in negative polarity to achieve this minimum dilution because an all weld metal clad is going to be harder than one heavily diluted with the parent.
2 layers is usually the norm to ensure the weld metal is completely free of dilution.
Great for hardfacing but not so great for sticking stuff together where you don’t want the extreme hardness and you want dilution.
If you were working on something critical or thick youd pre heat this in a lot of cases. The reason is simply to slow down the cooling rate.
2 layers is usually the norm to ensure the weld metal is completely free of dilution.
Great for hardfacing but not so great for sticking stuff together where you don’t want the extreme hardness and you want dilution.
If you were working on something critical or thick youd pre heat this in a lot of cases. The reason is simply to slow down the cooling rate.
I have a gas economiser i fit in line if doing a lot of oxy welding, when you put the torch down flame goes out, then when you pick it up again you just light if from the pilot flame and off you go no re setting the torch. Well worth the cost in both gas and time saved.
I've never seen one of those before, that's really cool. So top right has a little pilot flame and hanging the torch kills the gas? I guess the only concern is of the torch gets knocked off the hook without you realising.
Screwdriver
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My understanding is the "candle" is there to relight the torch, so it wouldn't get knocked off and burst into flames. You wouldn't leave it unattended but if you did, you wouldn't then be able to knock it over anyway. Looks like a great idea because I was always putting down the torch for fiddly little jobs and constantly relighting (and having to use both hands) was a real chore. Then I saw the price and decided I could live with that for now...
RonA
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ditto, looks like a nifty gadget to have if you practice what the Americans describe it in their books as “hammer welding” not to be confused with hammer welding in a forge. I can see what was meant by I can live without one for the present though
RonA
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Burdekin
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I have a gas economiser i fit in line if doing a lot of oxy welding, when you put the torch down flame goes out, then when you pick it up again you just light if from the pilot flame and off you go no re setting the torch. Well worth the cost in both gas and time saved.
That's a nifty idea. Main reason I use tig is I get tired or relighting the oxy torch. Oxy is such a lovely welding process, nice and quiet.
WorkshopChris
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Likewise until i stumbled upon one on eBay poorly describes as something like "welding torch and hose bracket"
Still in its box as NOS.
I only used oxy/a on cars etc until I got my mig and then the oxy/a was put on the back burner (excuse the pun) except for loosening seized components etc, could make some seriously smooth welds with oxy/a but that was over a 100 year ago.oxy acet welding is far smoother than mig and hardly needs anything grinding off it
slim_boy_fat
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Aye
Are you really that old?
brightspark
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did ya get your telegram from the queen 
use your zimmer frame to hold the torch
use your zimmer frame to hold the torch 