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Old 08-26-2017, 10:46 AM
vroom vroom is offline
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Default Panel joining

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.
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Old 08-26-2017, 11:39 AM
Dave K. Dave K. is offline
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Hi Tim,
First, I am beginner and a student of metalworking so I am learning but will share with you what I know. I am sure the experts will provide their guidance.

One of the experts in aluminum is Kent White Tinmantech. He believes in the Oxy-acetylene method, and because of this I have studied his approach.

In example, here is a video Kent has on OA welding that talks a bit about this. https://www.youtube.com/watch?v=aF1Srs_e1Aw (If link doesn't work search tinmantech on youtube 'how good is your TIG welding')

Kent is on this site and others will likely provide more. Also there are lots of videos on youtube as well as books on OA welding. TIG is great, I just have a hard time with it on thin sheet aluminum.

I would love to see the project you are working on if you would like to share pictures and your approach. I am learning, so I am sure you can teach me things!
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Old 08-27-2017, 02:20 AM
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neilb neilb is offline
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Quote:
Originally Posted by vroom View Post
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.
materials melt at their respective temperatures regardless if with O/A or TIG.
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Old 08-27-2017, 03:33 AM
lots2learn lots2learn is offline
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Quote:
Originally Posted by neilb View Post
materials melt at their respective temperatures regardless if with O/A or TIG.
Agree, from memory I think oxy is closer to 6000 and Tig around 11,000. I have a lot more experience Tig welding aluminum but would not use it for panels.Oxy is not brittle and easier to form after welding.
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Old 08-29-2017, 06:18 AM
Oldnek Oldnek is offline
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I think unless your your a scientist, disregard all temps and just weld with what ever you have at hand to get the job done right.
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Old 08-30-2017, 04:17 PM
ncologerojr ncologerojr is offline
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Of course o/a welding is great, but you can tig the panels as well. A lot of guys do. When I took a class with Wray Schelin he demonstrated that when tig welding aluminum if you run a bead with filler on the outside, and then just a quick fusion pass on the inside the joint is very, very strong. I've done this with motorcycle fuel tanks and I have never had a problem.
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Old 08-31-2017, 09:05 AM
Peter Tommasini Peter Tommasini is offline
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I dont like to sound like a smart a*se..... but for all of you that think that tig weld is as strong for joining body panels then OA ,... just do what Ken did on your tig weld and see how long it takes before it fails ........

so... it does not matter if you weld the inside or not (which by the way it takes too long ) it would simply BREAK!
Just try it and make up your own mind
Peter
PS David Gardner ,Jeff Moss, and many other professional around the world ,all use OA for welding and plenishing aluminium body panels with very little distortion and a well annealed panel to work with .....
I wonder why??
https://www.youtube.com/watch?v=aF1Srs_e1Aw
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Old 08-31-2017, 05:15 PM
Charlie Myres Charlie Myres is offline
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Good link Peter and Kent!

A simple test at home for people learning to weld, is to butt-weld two pieces of metal together about 100mm long and then bend the join along the weld to 180 degrees. Then check for failure on the back of the weld,

Cheers Charlie
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Old 08-31-2017, 06:15 PM
AllyBill AllyBill is offline
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I was brought up on OA but wouldn't touch it for welding panels.

Where people often go wrong with TIG welding aluminium is failing to pre-heat. OA takes a lifetime to warm anything so by the time the metal melts the job is pre-heated and already annealed. TIG puts a lot of energy in very quickly so the surrounding metal quenches it as you go an you get a brittle weld with poor penetration. Get it warm and it's quicker and simpler than ever OA was, in my humble opinion.
If you're new to it put a strip of thin steel over the back of your joint with Clecos to pull out any excess heat, hold the joint in position and contain the gas shield around the back. You can weld the holes up later. Tack weld every inch or so, stretch out with a hammer and dolly to keep the shape then fill in the gaps.

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Old 09-01-2017, 06:58 AM
cliffrod cliffrod is offline
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Quote:
Originally Posted by Peter Tommasini View Post
I dont like to sound like a smart a*se..... but for all of you that think that tig weld is as strong for joining body panels then OA ,... just do what Ken did on your tig weld and see how long it takes before it fails ........

so... it does not matter if you weld the inside or not (which by the way it takes too long ) it would simply BREAK!
Just try it and make up your own mind
Peter
PS David Gardner ,Jeff Moss, and many other professional around the world ,all use OA for welding and plenishing aluminium body panels with very little distortion and a well annealed panel to work with .....
I wonder why??
https://www.youtube.com/watch?v=aF1Srs_e1Aw
After more than one formal apprenticeships in different fields of craft, one of the things I have learned is to listen to a Master. Period. Shut up, listen and do what they say. When they tell you you're doing it wrong, there's a reason. That's why they are the Master and not the apprentice. It isn't always the fastest path to success, but it is the best path. Choose your Masters well and the rest is just hard work trying to be as good as they are.

When men like Peter and others mentioned (and not mentioned) choose and recommend OA, that's what I do. Anyone else can do what they like, including how their Masters taught them.

if you are going OA, get one of Kent's Meco Midgets. There are top tier experts around (Not including Kent) who say it is the best torch they have ever used. More inspiration for those of us nuts in the peanut gallery.

Personally, I think many modern people have some conscious or subconscious level of aversion to the old ways. The idea of the new way being better/faster/more whatever is the basis of progress. It isn't always so. Competency and fluency with any method has a lot to do with the amount of practice. If the modern method seems to eliminate the need for practice, that is not the path to being a better craftsman.
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