All MetalShaping

Go Back   All MetalShaping > Metal Shaping Projects > Automotive Projects
  Today's Posts Posts for Last 7 Days Posts for Last 14 Days  

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-03-2019, 09:41 AM
Onorius Onorius is offline
MetalShaper of the Month Dec. 2018
 
Join Date: Jun 2016
Location: Romania
Posts: 71
Default Zagato aluminum gas welding without filler rod?

What do you think, how this weld was made?

Name:  1.jpg
Views: 484
Size:  61.1 KB

Name:  2.jpg
Views: 474
Size:  56.3 KB

Name:  3.jpg
Views: 470
Size:  78.3 KB

Name:  4.jpg
Views: 480
Size:  73.5 KB

Name:  5.jpg
Views: 483
Size:  66.2 KB

Name:  6.jpg
Views: 484
Size:  63.1 KB

Name:  7.jpg
Views: 475
Size:  80.8 KB

Name:  8.jpg
Views: 477
Size:  81.4 KB

Name:  9.jpg
Views: 473
Size:  76.4 KB
__________________
Onorius

Last edited by galooph; 01-03-2019 at 10:00 AM.
Reply With Quote
  #2  
Old 01-03-2019, 11:01 AM
mastuart mastuart is offline
Member
 
Join Date: Oct 2016
Location: Mendota Il
Posts: 47
Default

No expert here. Looks like the last pictures are of the back side. If so it looks like the back side of a gas weld . Front side looks welded with little to no filler. I kind of think it can be done with lots of experience. I think I could do a short section if it was tacked with filler. I think I would be able to start at a tack and be able to fuse it together from tack to tack. But if I could get it done it would not look as good as the weld pictured.
__________________
Mark
Reply With Quote
  #3  
Old 01-03-2019, 01:57 PM
Stretch Stretch is offline
MetalShaper of the Month Aug 2016, Feb 2017, Sept 2018
 
Join Date: Dec 2014
Location: Cornwall, England
Posts: 424
Default

Looks like a typical 50/60s coachbuilder's gas weld - fused without adding rod. This type of welding was common at the time in the U.K. and Italy etc. It's not as difficult as people think. What it takes is a traditional approach to setting up the torch etc. and this is what is missing from today's teachings.
__________________
Matt
www.air-Kraft.com

Last edited by Stretch; 01-03-2019 at 02:05 PM.
Reply With Quote
  #4  
Old 01-03-2019, 03:46 PM
crystallographic crystallographic is offline
MetalShaper of the Month October '14 & April '16
 
Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
Posts: 3,009
Default

I've seen these welds on 1930's - 1960's Euro coachworks from Germany, Schweitz, UK, Spain and Italy.
I demonstrated this on my 1994 Aluminum Gas Welding DVD using O/A on horizontal and vertical welds, and filmed through the TM2000 lens.
https://www.tinmantech.com/products/...g-aluminum.php
Usually every time you see the ditch of incomplete metal thickness/lack of filler on the top of auto body welds (both steel and aluminum), it means that the welds were autogenous ... parent-metal welds, Scot welds, fusion welds ... etc and etc.
However, American aviation practice forbids this type of welding because of incomplete metal thickness, and therefore lack of strength.
(Aircraft Accepted Methods and Practices -AC43-13B)
__________________
Kent

http://www.tinmantech.com

"All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919.
Reply With Quote
  #5  
Old 01-03-2019, 05:14 PM
Chris_Hamilton Chris_Hamilton is offline
Member
 
Join Date: Jan 2013
Location: Southisde Virginia
Posts: 121
Default

Quote:
Originally Posted by Stretch View Post
Looks like a typical 50/60s coachbuilder's gas weld - fused without adding rod. This type of welding was common at the time in the U.K. and Italy etc. It's not as difficult as people think. What it takes is a traditional approach to setting up the torch etc. and this is what is missing from today's teachings.

Matt what exactly do you mean when you say a traditional approach to setting up the torch? Slightly carburizing flame???
__________________
Chris (trying to be the best me I can be)
Reply With Quote
  #6  
Old 01-03-2019, 07:32 PM
Peter Tommasini Peter Tommasini is offline
MetalShaper of the Month May 2013, Dec 2013
 
Join Date: Apr 2011
Location: Melbourne,Victoria, Australia
Posts: 7,573
Default

A similar question was asked on another tread about ally welding, this is what I have seen and practice over the Years
.................................................. .................................................. ........
There are a few techniques to weld alluminium I have seen it in Italy in 1967/68 at Scaglietti, and also at Carrozzeria Touring in Milan *Italy) when I visited there .
.................................................. .................................................. .................................................. .................................................. ...............
Years later, then living in Australia I did see and practice the way that the English tradesman did it in England at Aston Martin ,Rolls Royce. .. They did it a bit different but with the same results.

So here I will try to explain how

In Italy two people would weld a long and large panel, by one person holding the two panels together, and manipulating the panels so the next person (after preparing and fluxing the two panels) would run the oxy torch over the joint and melt the two parts together. Then the panel would get replenished and hammered up on a Maglio , then finished off by hand, this method is very hard to do, and I have only seen a few people doing it right.
I my self cannot get it .
I have seen two other methods from England tradesmen , The first method was... to turn (with a hand made tool) a very small edge upwards on each of the edges to be welded, then fuse those two edges together, ( again with oxy) meaning that the two upwards edges where used as filler rod. Then after washing the flux thoroughly, the panel would be planished on a stake dolly and then wheeled up . when with this method the panel was finished ,on the inside of the panel the penetration was nearly invisible , it looked like a mark done with a wet finger on the ally. I have tred that and it works rather well .

The next method is the normal conventional method to cut file and bevel the two edges , adjust and tack (again with oxy) then weld with a HOT but soft flame (this is called carbonizing flame ) then simply planish and wheel. The problem with this method.... YOU NEED to have the torch really really working well, WHY ? 1st...... because you do not want to have too much penetration, because that is only going to upset the planishing, 2nd...it might either have a cold weld (meaning it's too high) or a too hot weld causing holes and uneven weld

If you where to ask me which method I like better.. I would say that, once I have decided on the type of shape I will be welding, I would then decide which method I would use
__________________
P.Tommasini

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
Reply With Quote
  #7  
Old 01-04-2019, 03:58 AM
Stretch Stretch is offline
MetalShaper of the Month Aug 2016, Feb 2017, Sept 2018
 
Join Date: Dec 2014
Location: Cornwall, England
Posts: 424
Default

Quote:
Originally Posted by Chris_Hamilton View Post
Matt what exactly do you mean when you say a traditional approach to setting up the torch? Slightly carburizing flame???
The traditional approach calls for a wide, soft flame for gas welding aluminium. I can only give UK standard welding nozzle sizes (BOC etc.). Whereas for steel at 16 gauge (1.5mm) I would probably use a no2 nozzle at 3-4 psi of pressure, the same thickness in aluminium would require a 5 or 7 nozzle at around 2-3 psi of pressure. This gives a softer, wider gas cone and is much more suited to welding ali. The number 2 nozzle at 3-4 psi would generate pretty much the same heat and could technically weld ali, but due to its narrower cone and higher pressure it is a million times more likely to burn holes. The wider, gentler flame of a larger tip/nozzle creates a wider fusion pool and suits gas welding aluminium much, much better.

But, and here's the caveat: travel speed needs to be far greater than that of gas welding steel to achieve the desired results. I've never timed my welds, but I'd say travel speed in the region of 3x steel is required.

Torch angle is another critical factor - forget what the book may teach because for aluminium you really need to lean more to approximately 45 degrees. This aids forward flow when moving at the pace aluminium requires. A steel Type torch angle will promote burn through.

When one becomes proficient at gas welding aluminium, then it's time to start oscillating the torch in little circles. This promotes a slightly wider, more even fusion when not adding rod on body panels and reduces the "divets" that sometimes accompany gas welds as in the pictures above.

The process described above is the traditional British method taught to us at Lynx Engineering in the 1980s. We used to make complete aluminium bodies for 1950s race cars (mainly Jaguar D and C Type etc). We had the benefit of semi-retired artisans that had worked for Rolls Royce, Aston Martin and of course during WW2 they were making Spits, Hurricanes and Lancs etc., so they had a wealth of experience, which they duly passed on.

I'm in no way suggesting this is the only way as there are other methods, but from all I've learned over the years it is the only way I approach gas welding aluminium. It is pretty much a "lost art", with very little being taught correctly today, so info covering what I describe above may not be found in a book or might be contrary to writings. However, this is what the old timers at Lynx did, and it was born from their lifetimes' experiences.
__________________
Matt
www.air-Kraft.com
Reply With Quote
  #8  
Old 01-04-2019, 06:04 AM
Onorius Onorius is offline
MetalShaper of the Month Dec. 2018
 
Join Date: Jun 2016
Location: Romania
Posts: 71
Default

Peter Tommasini:
So here I will try to explain how

In Italy two people would weld a long and large panel, by one person holding the two panels together, and manipulating the panels so the next person (after preparing and fluxing the two panels) would run the oxy torch over the joint and melt the two parts together. Then the panel would get replenished and hammered up on a Maglio , then finished off by hand, this method is very hard to do, and I have only seen a few people doing it right.
I my self cannot get it .





I want to see if I get it right. This means no tack first?
__________________
Onorius
Reply With Quote
  #9  
Old 01-04-2019, 06:11 AM
Onorius Onorius is offline
MetalShaper of the Month Dec. 2018
 
Join Date: Jun 2016
Location: Romania
Posts: 71
Default

Quote:
Originally Posted by Stretch View Post
The traditional approach calls for a wide, soft flame for gas welding aluminium. I can only give UK standard welding nozzle sizes (BOC etc.). Whereas for steel at 16 gauge (1.5mm) I would probably use a no2 nozzle at 3-4 psi of pressure, the same thickness in aluminium would require a 5 or 7 nozzle at around 2-3 psi of pressure. This gives a softer, wider gas cone and is much more suited to welding ali. The number 2 nozzle at 3-4 psi would generate pretty much the same heat and could technically weld ali, but due to its narrower cone and higher pressure it is a million times more likely to burn holes. The wider, gentler flame of a larger tip/nozzle creates a wider fusion pool and suits gas welding aluminium much, much better.

But, and here's the caveat: travel speed needs to be far greater than that of gas welding steel to achieve the desired results. I've never timed my welds, but I'd say travel speed in the region of 3x steel is required.

Torch angle is another critical factor - forget what the book may teach because for aluminium you really need to lean more to approximately 45 degrees. This aids forward flow when moving at the pace aluminium requires. A steel Type torch angle will promote burn through.

When one becomes proficient at gas welding aluminium, then it's time to start oscillating the torch in little circles. This promotes a slightly wider, more even fusion when not adding rod on body panels and reduces the "divets" that sometimes accompany gas welds as in the pictures above.

The process described above is the traditional British method taught to us at Lynx Engineering in the 1980s. We used to make complete aluminium bodies for 1950s race cars (mainly Jaguar D and C Type etc). We had the benefit of semi-retired artisans that had worked for Rolls Royce, Aston Martin and of course during WW2 they were making Spits, Hurricanes and Lancs etc., so they had a wealth of experience, which they duly passed on.

I'm in no way suggesting this is the only way as there are other methods, but from all I've learned over the years it is the only way I approach gas welding aluminium. It is pretty much a "lost art", with very little being taught correctly today, so info covering what I describe above may not be found in a book or might be contrary to writings. However, this is what the old timers at Lynx did, and it was born from their lifetimes' experiences.

This is very valuable information, thanks for posting
__________________
Onorius
Reply With Quote
  #10  
Old 01-04-2019, 10:10 AM
Stretch Stretch is offline
MetalShaper of the Month Aug 2016, Feb 2017, Sept 2018
 
Join Date: Dec 2014
Location: Cornwall, England
Posts: 424
Default

Onorius - you are welcome!

The method Peter describes of one person holding the panel moving it up and down whilst the other welds is very accurate also! At Lynx I would sometimes do the holding and tweeking up and down whilst Frank Knight would weld from start to finish without a single tack! He could also weld two large aluminium panels together without a single tack by himself!!! He was and is the only person to date I've ever seen do this in my 35 years of working in classic car restoration. Miss you Frank! R.i.P. old buddy.

Matt
__________________
Matt
www.air-Kraft.com
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -5. The time now is 10:17 AM.

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.