All MetalShaping

Go Back   All MetalShaping > General Metal Shaping Discussion > Welding Sheet Metal
  Today's Posts Posts for Last 7 Days Posts for Last 14 Days  

Reply
 
Thread Tools Search this Thread Display Modes
  #31  
Old 12-12-2014, 01:15 PM
Patrick DeZeeuw Patrick DeZeeuw is offline
Member
 
Join Date: Dec 2014
Location: Dallas Texas
Posts: 26
Default

Quote:
Originally Posted by Steve Hamilton View Post
Patrick

In your video you are welding on rather small pieces of aluminum.
I am not an expert gas /alum. Welder but I think you would have better results & be more consistent with larger panels, that change temp slower.
I would use about 1 sq. foot cut in half.

I usually suggest that beginners first practice running a puddle across a panel (not a joint) when you are able to control the puddle width, then do the same while adding filler metal.

Only after learning good puddle control would I suggest welding a joint.

Steve
Steve thank you.

I am going to pick up some .063" today. Unfortunately it seems being Dutch we like to take on monumental tasks. Our last name means 'sea land' our ancestors are from province in the Netherlands call Zealand. de Zeeuw is our name meaning of the "sea land" So I am pretty sure some pretty gal asked a young Dutchman to build her a garden where the ocean was... Zeke says, "dad you make me do the really hard thing so that the hard things aren't so hard." Our family crest says "Luctor Et Emergo" which is "I struggle I rise"

Thank you.
__________________
Patrick
Reply With Quote
  #32  
Old 12-12-2014, 01:33 PM
Patrick DeZeeuw Patrick DeZeeuw is offline
Member
 
Join Date: Dec 2014
Location: Dallas Texas
Posts: 26
Default

Quote:
Originally Posted by crystallographic View Post
You are welcome, Patrick.
Theoretically, the oxy-acet torch flame does consume all oxygen - and for mild steel and 4130 Chromemoly it effectively does it well enough - so this is why those alloys do not need a welding flux for oxy-fuel welding. So you are correct, for those two groups.

However, for those alloys more sensitive to welding oxidation, a flux is needed beyond the "neutral" flame envelope -i.e. aluminum alloys, stainless, Inconel, copper, magnesium, titanium, and others.

The oxidation protection provided by the correct welding flux is therefore non-trivial, and the torch flame setting is specific to the metal alloy, since this is really about chemistry impacting welding metallurgy. For aluminum alloys, the US Navy, ALCOA, and the Aluminum Association all recommend that the torch flame be set with a slight excess of acetylene (for the carburetion guys: a fuel-rich setting). These industry PhD's all specify this flame setting to assure the weldor of a non-oxidizing flame. The telltale feather of a carburizing flame is the single useful indication of a non-oxidizing flame, in the field.

For oxy-fuel welding aluminum alloys specifically, the actual welding flux formulation can affect the actual welding procedure for flame setting and flux application.

hope this bit helps a little,
For some reason I am not getting all email updates and missed your post. That answers my question and now I understand "why" the flux is not just breaking the oxidation down but also protecting the weld from it...btw your superpremium flux is amazing. This string has been very enlightening and apparently Zeke's been paying more attention to your videos than I have been for he seems to be doing it right and I'm doing it wrong so now let's see if the old man can give the young whippersnapper a run for his money.
__________________
Patrick
Reply With Quote
  #33  
Old 10-13-2015, 03:39 PM
crystallographic crystallographic is offline
MetalShaper of the Month October '14 , April '16, July 2020, Jan 2023
 
Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
Posts: 4,388
Default

Quote:
Originally Posted by Patrick DeZeeuw View Post
For some reason I am not getting all email updates and missed your post. That answers my question and now I understand "why" the flux is not just breaking the oxidation down but also protecting the weld from it...btw your superpremium flux is amazing. This string has been very enlightening and apparently Zeke's been paying more attention to your videos than I have been for he seems to be doing it right and I'm doing it wrong so now let's see if the old man can give the young whippersnapper a run for his money.
Patrick,
Give him a good run for his money - those whippersnappers need the "grey dog challenge."

Yes, the super premium is a huge relief for my aluminum welding (dirty gas here) - I like those well-defined ringlets!

P1140130 copy.jpg
__________________
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
  #34  
Old 10-16-2015, 12:16 PM
Steve Colby Steve Colby is offline
Member
 
Join Date: Jun 2009
Posts: 35
Default Questions

With the tooth paste type flux that we use when Q/A welding Aluminum at what tempt. does it change from paste to liquid and flow. I believe this happens around 800 to 900 degrees ?
Also in one of Ken Whites videos, I believe that he suggested using a tip size with an opening 3/4 the metal thickness. This can be done by inserting a tip cleaner in the hole and measuring it, and knowing your metal thickness and doing a little math, it sounds like a good starting point?
Reply With Quote
  #35  
Old 10-16-2015, 05:04 PM
Stretch Stretch is offline
MetalShaper of the Month Aug 2016, Feb 2017, Sept 2018, Dec 2020, Aug 2022
 
Join Date: Dec 2014
Location: Cornwall, England
Posts: 550
Default

I've always found that reducing gas pressure down to 2-3 psi and using a no5 tip works absolute wonders on 16g aluminium. This produces a wider, 'softer' flame that is much more forgiving. I rarely add filler rod when butt welding sheet body panels and always oscillate the torch in a series of circular motions as I work along the panel. This process was taught to me by my mentor back in 1984, who learned his trade at Rolls Royce in the 1930s and then building Spitfires during WW2. To this day, he was the only person I have ever seen weld large ali panels together without any tack welds - a very difficult process!

The circular motions of the torch help to dissipate the heat evenly across both panels and reduces the chance of burning through dramatically. The weld bead using this process is excellent and the penetration is almost a mirror image of the upper bead. The welds always passed all testing and inspections to aviation standards.

I have watched many YouTube videos of people welding aluminium, and to date haven't seen anyone weld in a similar fashion. I'm also surprised by how often people burn through on videos.

Perhaps the method I was taught died out with the old schoolers - I have no idea. One thing I will say is that this method requires speed. Judging by the YouTube stuff I've seen, many people tend to weld ali pretty much at the same speed they would gas weld steel. From my experience, aluminium welds so much better with a wider, softer flame at pace. Maybe it's horses for courses, but burning through is much reduced, pretty much to the point of being excluded. I tend to agree that lifting the torch on and off the panel induces oxidation and therefore the tendency for burn through. The tell-tale sign of a little bit of blackening happens in a second or two. Very difficult to then reflow the ali pool forward, as it has then a tendency to part like a breaking a-frame wave, causing a burn through.

The above is just my experience on welding aluminium. There are, of course, many ways of achieving the same results. I am in no way implying anyone else's method is wrong!
__________________
Matt Keene
www.air-Kraft.com
Reply With Quote
  #36  
Old 10-16-2015, 05:25 PM
elavir elavir is offline
MetalShaper of the Month May '17
 
Join Date: Dec 2014
Location: Holland
Posts: 157
Default

Hi Matt,

What is the inner diameter of the tip no 5 you are using.

Cheers Richard.
__________________
Richard
Reply With Quote
  #37  
Old 10-16-2015, 08:25 PM
sblack sblack is offline
Member
 
Join Date: Sep 2011
Location: Montreal
Posts: 382
Default

As a rank amateur, i find it easier to reduce the flame if it is welding a bit too hot rather than pulling back. I know more experienced welders can control the heat with ease, I even saw one madman weld aluminum with a cutting torch . But for me adjusting the flame so that I can maintain a pace that is comfortable for me makes things easier. If I turn it up too much i have to go faster than my skill level and it ends up uneven or I blow holes and if the flame is too cold I can't get a rhythm going either. When it is just right, and I have the work piece at the right temperature, I can do a nice consistent weld. Lately I have been experimenting with reducing the bead thickness to minimize planishing and I am making progress gradually. But the main thing is to get the settings and rhythm and coordination so that you can lock into that sensation and remember it and reproduce it.

I am usually welding 0.050" and I think it is the #2 meco that I use.

I learned my welding on my own using Kent's videos. All of the techniques and products (torch, flux, googles) have worked really well for me. He has been welding, teaching and researching for a long time and his knowledge covers a vast range of metal working. I don't have the experience to comment one way or the other on other traditions or techniques. I hope this perspective from a successful beginner is helpful.
__________________
Scott in Montreal
Reply With Quote
  #38  
Old 10-17-2015, 12:31 PM
crystallographic crystallographic is offline
MetalShaper of the Month October '14 , April '16, July 2020, Jan 2023
 
Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
Posts: 4,388
Default Oxy-acetylene, oxy-hydrogen, oxy-propane welding of aluminum

As far as tip sizes go, the tip size - per - metal thickness chart that we offer was posted earlier in this thread.

It is very helpful to measure by marked tip size using this chart, because tip sizes are not entirely consistent between manufacturers. Or, you can also use the non-cutting ends of wire drills to measure orifice diameter - which directly corresponds to metal thickness.

However, tip size may not be an exact science, as I have learned by trying many different torches and tips. For .050" 3003 aluminum, a tip orifice diameter of .035" is a good rough start. You can go either up or down in tip diameter from there. And, if your metal has been shaped you will find that your edge thickness has either increased or decreased, so best to be aware of that variation when choosing an exact tip size.

OH2 cuttorch_aluminum_2.jpg
Sometimes a flange weld is a good way to determine how a tip size is performing as there is no filler rod used and the bead is well-defined.
(.050" 3003, welded with oxy-hydrogen from a small Victor cutting torch)

I have tried many torches and many tip sizes, along with every flux I could find and every bottled water I could locate across the US and parts of Europe. I've gone to the flux companies and have spoken to their tech-reps, and have had formulas made or changed. Sigh, I've been at this for a while and have wanted to eliminate as many fundamental problems as I could. I've spoken to aircraft welders who welded, instructed and managed welding crews for Beech, Waco, Steerman, Boeing, Northrop, Lockheed, Travel Aire, Command Aire, Martin-Marietta, and others I cannot remember. The Aluminum Association has been a very good source of people, information and history. Their annual Conferences and their book, "Aluminum Welding and Practice" are very worthwhile.

The only fuel gases I have tried are Acetylene, Hydrogen and Propane.
P1150602 copy.jpg

I use a 30deg angle of tip to metal surface (recommended by ALCOA) and generally have the acetylene flame set so that the inner cone is a nickel's thickness from the aluminum surface. Hydrogen usage (no inner cone easily visible) puts the torch tip end about 3/4 inch from the aluminum surface, but you can set it closer than that, if you wish.

Personal technique varies enough that the aviation weld inspectors have said that they could identify the weldor by their welds.

Personally, I manage heat control during my welding by flick-twisting my wrist a tiny bit to change the angle of the flame to the work by 10 to 20 deg. This also makes defined ringlets in the weld bead, and also heats the weld zone ahead of my weld. It is also a standard method used for decades in the aircraft factories.

P1130433 fusion copy.jpg
Fusion welding, shown here, is a way to weld without adding filler metal. It is one of the standard methods used in the auto body industry, both in Europe and the US until handmade/hand assembled bodies were discontinued.
Drawback: incomplete metal thickness, and the subsequent "ditch" showing in the weld seam - visible on numerous Rolls, Maserati, and etc bodies. Of course, with additional time and effort the edges may be thickened by upsetting or have metal "added" by lipping.

Fusion welding in aviation is not permitted by the US Aviation Standards book, AC 43-13-B, which specifies that all welds shall be full thickness and no filing or sanding is permitted.

For my own work I use .035" filler or thinner. I will fusion weld in some cases but the parts are limited to automotive paint-grade examples only.

Tacking the weld seam first is a very common practice, in both fields of automotive and aviation. Planishing the tacked seam is also common, prior to welding complete. Fusion welding an entire seam without tacking is also a method used by production panel makers. Personally, I recommend learning the accepted methods completely, and then vary them to suit your job and your talent.

I am not an expert on this stuff, but am just trying to fill a few gaps until a real expert comes along....
Attached Images
File Type: jpg oxy_hydrogen_oxy_propain_welds_top.jpg (20.9 KB, 14 views)
__________________
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.

Last edited by crystallographic; 10-17-2015 at 12:42 PM.
Reply With Quote
  #39  
Old 10-17-2015, 12:55 PM
Stretch Stretch is offline
MetalShaper of the Month Aug 2016, Feb 2017, Sept 2018, Dec 2020, Aug 2022
 
Join Date: Dec 2014
Location: Cornwall, England
Posts: 550
Default

Kent's example of a fusion weld shown in the above picture he offers is a perfect example of a very good butt jointed fusion weld. I bet the penetration bead is also similarly consistent. This weld would planish up nicely with a hammer and dolly and would almost disappear when wheeled through an E-wheel. That weld is typical of that from a traditional English style panel beater from my experience. Notice the consistency - very even with a good weld bead width - just what the doctor ordered!

When I get the time I'll post up some samples of my welds for comparison. This may take a while as I'm flat out crazy busy at the mo!!!

Richard - I'll measure up a no5 on Monday and let you know.

Regards, Matt.
__________________
Matt Keene
www.air-Kraft.com
Reply With Quote
  #40  
Old 10-17-2015, 05:26 PM
crystallographic crystallographic is offline
MetalShaper of the Month October '14 , April '16, July 2020, Jan 2023
 
Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
Posts: 4,388
Default

Quote:
Originally Posted by Steve Colby View Post
With the tooth paste type flux that we use when Q/A welding Aluminum at what tempt. does it change from paste to liquid and flow. I believe this happens around 800 to 900 degrees ?
Yes, Steve,
From what I have learned about the welding, brazing and soldering fluxes, the industry formulates the chemistry so that the flux melts and runs out just before the filler flows. In this way, each flux gives its visible indication when at the appropriate active temperature. Now,which aluminum gas welding flux melts at precisely what temperature I cannot say, but it is below the melting point of both the parent alloys and the filler metals.

Perhaps I should add here that the welding, brazing and soldering flux chemistry is also formulated for each alloy and purpose, on copper, aluminum, iron, stainless etc.
__________________
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.

Last edited by crystallographic; 10-17-2015 at 05:30 PM.
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 Off

Forum Jump

All times are GMT -5. The time now is 10:43 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.