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  #11  
Old 09-01-2017, 08:58 AM
sblack sblack is offline
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OA works great. The flux for aluminum is a pain to clean off the work and your tools but other than that it works very well. Besides, a torch is a very handy thing to have in the shop for dozens of other jobs, like stubborn bolts, bending stuff, annealing, and heating your tea.

But, feel free to experiment and see for yourself.
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  #12  
Old 09-01-2017, 07:55 PM
AllyBill AllyBill is offline
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Never forget that just because something has always been done the same way that this is necessarily the best way. Question everything, this is how progress is made.

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  #13  
Old 09-01-2017, 11:08 PM
crystallographic crystallographic is offline
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Quote:
Originally Posted by vroom View Post
I have been building a car body at http://www.metalmeet.com/forum/showthread.php?t=11470
So far I have figured out pretty much everything right up to joining panels together. Now I need some advice. I can butt weld thin sheet steel pretty well using OA or TIG but my car's body is aluminum so I have been trying to learn to TIG my panels. The whole subject seems pretty complicated and I wonder if it is worth the time it will take me to learn TIG.

The problem seems to be too much heat. I have read that an OA torch flame burns at 3200° F and a TIG torch something like 34000° F. So it is no surprise it is more difficult to control.

The old car guys all built bodies with OA. But, the modern guys seem to use TIG. If we could have a discussion of the pros and cons of each the decision might be easier to make.
Hi Tim,
You don't give your alloy or thickness here, though I will toss out a few thoughts, anyway.

In many of the race segments of American auto fabrication it is common for those craftsmen to gas weld the aluminum fuel tanks. Young, old, or modern - same thing. The dragster guys still torch weld the aluminum bodies. The restoration guys or repro body-fab guys still gas weld those Cobra/Porsche/ etc. bodies.

Yes, there are more tig-boys now, but then Lincoln and Miller have been promoting their gear at the auto/aviation events since the early nineties. And now even HarboFrate carries cheap tig and mig. Prices are down and availability is up.

Personally, I started with tig. I went to school and learned it and used it at my workplace. I owned a torch and stick welder at home and used them a lot. Eventually came the day when laying on my back welding up the back side of an aluminum seam, after having already welded the top of the seam, that one of the senior craftsmen (Rolls Royce, RAF, Park Ward, etc panel man) yelled at me as he walked past: "why the f. don't you go get the f'ing torch and stop f'ing around with that f'ing tigwelder???" Loud enough that most of the hangar could hear him. Harry Morrow was very Irish, you see.

So I did, after figuring all of that aluminum O/A esoterica out, first. I got the flux, struggled with eyewear, and figured out the tip size for .063 3003. And after a few false starts I was O/A tacking and welding like I had been doing on 20 ga crs for the previous 3 years.

Heat control with the torch does not use a foot pedal. It is tip size, flame setting, and angle of the torch to the work. Speed of your torch hand compensates for cool flame or hot flame.
Less flux in the weld is less to clean up.
Keep the weld zone clean, just like a tigboy does, with 91% isopropyl and the ss toothbrush.
For new aluminum just coat the rod with the primo flux. For resto/repair work coat the rod and one side of the work, with the primo flux.
Close fits help, but are not essential - if you have a good hand.
Horizontal "in position" work is best to start.
Horizontal on a vertical panel is next, "out-of-position."
And Vertical down is after that.
Overhead is last and required good patience, steady hand, and keen eyesight, and wear leathers against the hot drips.
Practice backhand and forehand, and step-back. Weld with either hand. (If you catch a hand problem you might be forced to learn, anyway ...?)
I have trained a lot of people to weld aluminum with O/A, over time.

For an authentic aviation lap seam using O/H, see this footage on F'book:
https://www.facebook.com/19094894868...type=2&theater

I have used an old Victor cutting torch for O/A welding of .050 3003 in public demonstrations, over the years.

The welders at Beech in the 1930's and 40's used to practice torch welding steel by welding their name in the air.
Beech 18's have some incredible welding on their gear legs. (landing gear)
name in air.jpg
This is just aluminum welding, though.

Good luck.
Post some images of your attempts, if you wish.
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Last edited by crystallographic; 09-01-2017 at 11:19 PM.
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  #14  
Old 09-02-2017, 03:19 AM
Dave K. Dave K. is offline
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Kent, Beautiful penmanship!
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  #15  
Old 09-02-2017, 10:44 AM
vroom vroom is offline
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Nice discussion and thanks to all those that contributed.

I am trying to weld .050 3003 AL. My TIG welder is a Miller Die nasty 200 so it will go down to 5 amps. It is a great machine and I love it for steel BUT when I saw a video of Kent putting the first tack on a joint while holding one of the panels in his hand I knew gas was IT.

I still have one question. Has anyone used propane instead of acetylene for torch welding? It burns at 4000°F rather then 6300°F but is a lot more available here in the sticks.
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  #16  
Old 09-02-2017, 11:05 AM
crystallographic crystallographic is offline
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Default oxy-propane on 3003 .050 using Meco with OX tip

Quote:
Originally Posted by vroom View Post
i still have one question. Has anyone used propane instead of acetylene for torch welding? It burns at 4000°f rather then 6300°f but is a lot more available here in the sticks.
P1150602 propane copy.jpg
P1150604 propane root copy.jpg
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  #17  
Old 09-02-2017, 01:22 PM
sblack sblack is offline
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Quote:
Originally Posted by vroom View Post
Nice discussion and thanks to all those that contributed.

I am trying to weld .050 3003 AL. My TIG welder is a Miller Die nasty 200 so it will go down to 5 amps. It is a great machine and I love it for steel BUT when I saw a video of Kent putting the first tack on a joint while holding one of the panels in his hand I knew gas was IT.

I still have one question. Has anyone used propane instead of acetylene for torch welding? It burns at 4000°F rather then 6300°F but is a lot more available here in the sticks.
Lots of airplane builders in WI. It can't be that hard to find acetylene if you can find oxygen.

Btw, Kent makes it look so easy, but whe you start it is hard, but then it actually becomes that easy, like riding a bike. You just have to murder some helpless coupons. That's what I did and I can weld with complete confidence in the flat position and semi confidence in the vertical position. If I practised more I would be fine in the vertical too. I learned solely form watching the tinman videos and I had no prior welding experience. Welders look at me strange when I tell them I learned how to weld on thin aluminum with a torch. I never tell them how easy it is. I'd rather they think I was some kind if genius

You have to work the panel as you tack to get things lined up and that results in flux getting on your tools. It washes off with water. If you forget to wash it you will be sorry. It's corrosive like crazy. Ask me how I know. And the work has to be very thoroughly washed in clean hot water to get all the flux off or the paint won't stick.
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  #18  
Old 09-02-2017, 02:36 PM
Dave K. Dave K. is offline
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Scott, great post! I agree, it is hard to weld with OA on aluminum, and I still struggle after two years of trying. That being said, I have also done Kent's hammer test, and was able to duplicate it, and my TIG welds broke. Though my welds are nearly as ugly as I am, I am confident with patience I can OA weld panels together. I like the fact that I can then 'smooth' out the panels and shape them without the welds breaking. Even for a beginner, it has been rewarding knowing that I can replicate the strength of Kent's welds.

The key for me has been to follow Kent's process to the letter. Even for a bad welder the process works.
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  #19  
Old 09-02-2017, 03:32 PM
Chris_Hamilton Chris_Hamilton is offline
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Quote:
Originally Posted by Dave K. View Post
Scott, great post! I agree, it is hard to weld with OA on aluminum, and I still struggle after two years of trying. That being said, I have also done Kent's hammer test, and was able to duplicate it, and my TIG welds broke. Though my welds are nearly as ugly as I am, I am confident with patience I can OA weld panels together. I like the fact that I can then 'smooth' out the panels and shape them without the welds breaking. Even for a beginner, it has been rewarding knowing that I can replicate the strength of Kent's welds.

The key for me has been to follow Kent's process to the letter. Even for a bad welder the process works.

Try using Kent's TM2000 welding lens. It really makes a difference in how you can see the weld zone when doing aluminum. Helps with steel too.
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  #20  
Old 09-02-2017, 06:56 PM
sblack sblack is offline
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Quote:
Originally Posted by Chris_Hamilton View Post
Try using Kent's TM2000 welding lens. It really makes a difference in how you can see the weld zone when doing aluminum. Helps with steel too.
I had no prior knowledge so I got everything from TM. Lense, headgear, flux, meco torch etc. It all works and he stands behind it. His 2 video set is the most thorough treatment of welding and brazing aluminum I have seen. Think of it... a TWO dvd set. He covers all the main alloys we use, 3003, 6061, 5052. Tons of detail on torch setup and lots of just welding so you can see the torch, filler and puddle. He uses his lense for the camera so it's very clear. This is the part that helped me the most.

Kent I take checks or cash
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