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  #1  
Old 01-08-2018, 03:02 PM
elavir elavir is offline
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Default Gaswelding difficulties

One of the difficulties of gaswelding aluminum i think is welding over the tacks. When
you've adjusted the torch to make the final weld and you're going fine till you must
run over a tack. In my experience the setting with gaswelding is for a tight material
thickness( I don't know how to explain it in an other way) When you reach the tack, which
is a bit thicker, the flame has insuficiant heat to let it melt in the same way as it
could with the sheet. I tackle this to grind the tacks to the same thicknes as the sheet
, which works well, but this is timeconsuming and you have to be careful not to ruin the
sheet. Sounds this familiar and is there an easier way to solve this? All suggestions are
welcome.
Cheers Richard.
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  #2  
Old 01-08-2018, 04:11 PM
Peter Tommasini Peter Tommasini is offline
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Richard
You have the right idea but do not grind the weld simply use the file, reason you can impregnate stone residue on to the ally and that can cause problem on your run also make sure to wash all the old flux from the tacks right off so you can start the weld from a clean surface ,make sure to use acetone to clean the surfaces inside and out

Here a tip for you........ to get best result for a flat weld and tack, file the two top edges of your panels off, so they are not square edges, they must look something like this V also it's best to have little penetration as possible so you can hammer your weld right out ,what that means you must be quicker on your speed when welding and have the torch with a feather (carbonizing flame)


PS ... VERY IMPORTANT.....do not hammer any tacks or weld... while the flux is on the surface, you will impregnate flux on to the ally ....the painters will hate you for it!!

Peter
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Last edited by Peter Tommasini; 01-08-2018 at 04:49 PM.
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  #3  
Old 01-09-2018, 01:51 PM
elavir elavir is offline
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Originally Posted by Peter Tommasini View Post
Richard
You have the right idea but do not grind the weld simply use the file, reason you can impregnate stone residue on to the ally and that can cause problem on your run also make sure to wash all the old flux from the tacks right off so you can start the weld from a clean surface ,make sure to use acetone to clean the surfaces inside and out

Here a tip for you........ to get best result for a flat weld and tack, file the two top edges of your panels off, so they are not square edges, they must look something like this V also it's best to have little penetration as possible so you can hammer your weld right out ,what that means you must be quicker on your speed when welding and have the torch with a feather (carbonizing flame)


PS ... VERY IMPORTANT.....do not hammer any tacks or weld... while the flux is on the surface, you will impregnate flux on to the ally ....the painters will hate you for it!!

Peter
Hi Peter, thnx for all the information. I'll try to put it into practice

Cheers Richard.
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  #4  
Old 01-09-2018, 03:04 PM
Stretch Stretch is offline
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Hi Richard.

For aluminium (16 gauge) I would highly recommend trying either a no5 or no7 BOC style (UK) welding nozzle and, most importantly, turn the gas pressure down to 2-3 psi max. You want a soft, fat flame. A lot of beginners make the mistake of running a too narrow flame cone, with higher than necessary flame pressure, which inputs too much heat into a thin weld zone causing burn through. Also, you have to weld aluminium at a very quick pace with oxy-acetylene. We are talking almost feet per minute as opposed to inches per minute a la steel. This is where the true art to gas welding ali comes in to form. Fast, fast, faster!

I seldom add rod to the puddle on ali body panels - for me the rod is there literally to start the weld then finish the last 1/4" of weld.

Also, I was taught to oscillate the torch in continuous circles to the width of approximately 1/4" - 3/8" around the weld zone as you move the torch along its path. This, apparently, was the norm during WW2 era to decrease the intensity of the heat affected zone according to my mentor. It is said to even out the h.a.z. a little, which reduces stress. This method, with good practice, should produce a lovely, flat bead with perfect penetration: A weld that needs no filing and only planishing or wheeling to make the weld virtually disappear.

Don't get me wrong, there are many ways of gas welding aluminium, but this is what I was taught and I find it works fantastically well.

On a side note... and this is one that's sure to raise eyebrows: I only flux the edges of the metal and not the full width of the weld bead. I find there is more than enough flux on just the edges to facilitate a perfect weld. The advantage is that flux glare is massively reduced and you have a more even temperature distribution. Again, a nugget that was passed down to me during my apprenticeship in the 1980's.

Regards, Matt
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  #5  
Old 01-09-2018, 04:03 PM
Gareth Davies Gareth Davies is offline
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Originally Posted by Stretch View Post
On a side note... and this is one that's sure to raise eyebrows: I only flux the edges of the metal and not the full width of the weld bead. I find there is more than enough flux on just the edges to facilitate a perfect weld. The advantage is that flux glare is massively reduced and you have a more even temperature distribution. Again, a nugget that was passed down to me during my apprenticeship in the 1980's.

Regards, Matt
Matt, that is a proper nugget and one worth remembering. Out of interest, what sort of lens do you use when oxy acetylene welding ally? I keep on seeing people recommend the ones that Kent White sells but was wondering if there is anything comparable here in the UK. Cheers.
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  #6  
Old 01-10-2018, 01:05 PM
Stretch Stretch is offline
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Originally Posted by Gareth Davies View Post
Matt, that is a proper nugget and one worth remembering. Out of interest, what sort of lens do you use when oxy acetylene welding ally? I keep on seeing people recommend the ones that Kent White sells but was wondering if there is anything comparable here in the UK. Cheers.
Hi Gareth. For 30 years I have simply used traditional old BOC style goggles with either green or a brownish type lense. Never had a problem. However, I've been reading on here about blue cobalt lenses and out of curiosity want to give them a go to see what all the fuss is about. I've managed to score a new old stock 1950's set of goggles with cobalt blue glass lenses. I've yet to try welding with them, but have tried them on and the world seems a whole lot more abstract!

I'll let you know how I get on

Cheers, Matt
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  #7  
Old 01-11-2018, 01:38 PM
Jim Tomczyk Jim Tomczyk is offline
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Quote:
Originally Posted by Gareth Davies View Post
Matt, that is a proper nugget and one worth remembering. Out of interest, what sort of lens do you use when oxy acetylene welding ally? I keep on seeing people recommend the ones that Kent White sells but was wondering if there is anything comparable here in the UK. Cheers.
Hi Gareth
I found some UK eye wear for OA Ali welding a little while ago that work well by taking out the orange flare and protect - see the following link

http://allmetalshaping.com/showthread.php?t=9151

Jim

Ps the vibroshear is getting some use 👍
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  #8  
Old 01-09-2018, 04:25 PM
Peter Tommasini Peter Tommasini is offline
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Quote:
Originally Posted by Stretch View Post
Hi Richard.

For aluminium (16 gauge) I would highly recommend trying either a no5 or no7 BOC style (UK) welding nozzle and, most importantly, turn the gas pressure down to 2-3 psi max. You want a soft, fat flame. A lot of beginners make the mistake of running a too narrow flame cone, with higher than necessary flame pressure, which inputs too much heat into a thin weld zone causing burn through. Also, you have to weld aluminium at a very quick pace with oxy-acetylene. We are talking almost feet per minute as opposed to inches per minute a la steel. This is where the true art to gas welding ali comes in to form. Fast, fast, faster!

I seldom add rod to the puddle on ali body panels - for me the rod is there literally to start the weld then finish the last 1/4" of weld.

Also, I was taught to oscillate the torch in continuous circles to the width of approximately 1/4" - 3/8" around the weld zone as you move the torch along its path. This, apparently, was the norm during WW2 era to decrease the intensity of the heat affected zone according to my mentor. It is said to even out the h.a.z. a little, which reduces stress. This method, with good practice, should produce a lovely, flat bead with perfect penetration: A weld that needs no filing and only planishing or wheeling to make the weld virtually disappear.

Don't get me wrong, there are many ways of gas welding aluminium, but this is what I was taught and I find it works fantastically well.

On a side note... and this is one that's sure to raise eyebrows: I only flux the edges of the metal and not the full width of the weld bead. I find there is more than enough flux on just the edges to facilitate a perfect weld. The advantage is that flux glare is massively reduced and you have a more even temperature distribution. Again, a nugget that was passed down to me during my apprenticeship in the 1980's.

Regards, Matt
Right on Matt!!!!!!!
Peter
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Metalshaping tools and dvds
www.handbuilt.net.au

Metalshaping clip on youtube
http://www.youtube.com/watch?v=WEAh91hodPg

Making Monaro Quarter panel:
http://www.youtube.com/watch?v=KIpOhz0uGRM
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  #9  
Old 01-11-2018, 02:44 PM
elavir elavir is offline
MetalShaper of the Month May '17
 
Join Date: Dec 2014
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Quote:
Originally Posted by Stretch View Post
Hi Richard.

For aluminium (16 gauge) I would highly recommend trying either a no5 or no7 BOC style (UK) welding nozzle and, most importantly, turn the gas pressure down to 2-3 psi max. You want a soft, fat flame. A lot of beginners make the mistake of running a too narrow flame cone, with higher than necessary flame pressure, which inputs too much heat into a thin weld zone causing burn through. Also, you have to weld aluminium at a very quick pace with oxy-acetylene. We are talking almost feet per minute as opposed to inches per minute a la steel. This is where the true art to gas welding ali comes in to form. Fast, fast, faster!

I seldom add rod to the puddle on ali body panels - for me the rod is there literally to start the weld then finish the last 1/4" of weld.

Also, I was taught to oscillate the torch in continuous circles to the width of approximately 1/4" - 3/8" around the weld zone as you move the torch along its path. This, apparently, was the norm during WW2 era to decrease the intensity of the heat affected zone according to my mentor. It is said to even out the h.a.z. a little, which reduces stress. This method, with good practice, should produce a lovely, flat bead with perfect penetration: A weld that needs no filing and only planishing or wheeling to make the weld virtually disappear.

Don't get me wrong, there are many ways of gas welding aluminium, but this is what I was taught and I find it works fantastically well.

On a side note... and this is one that's sure to raise eyebrows: I only flux the edges of the metal and not the full width of the weld bead. I find there is more than enough flux on just the edges to facilitate a perfect weld. The advantage is that flux glare is massively reduced and you have a more even temperature distribution. Again, a nugget that was passed down to me during my apprenticeship in the 1980's.

Regards, Matt

Hi Matt, thanks for your explanation and tips.
One thing that I don't understand is the oscilating of the weld. Is this done after welding?

Cheers Richard.
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  #10  
Old 01-12-2018, 12:16 PM
Stretch Stretch is offline
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Originally Posted by elavir View Post
Hi Matt, thanks for your explanation and tips.
One thing that I don't understand is the oscilating of the weld. Is this done after welding?

Cheers Richard.
I think the best way to describe it is to do a video! I'll do one next week and post a link on here.

Cheers, Matt
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