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Wed Jun 18, 2008 1:06 pm

Ok, I did read some of the welding equipment posts here, but I wanted to ask a specific question and solicit response from people with experience in this area.

I will be launching into the resto metal work of a very rusty '51 Beetle later this summer, lots of heater channel, patching, metal work, etc.

I have a Miller MIG, have used MIGs for about 6+ years, and would characterize myself as "minimally proficient".

Recently I started looking into TIG outfits. Mostly because I have seen some TIG resto panel work that is simply beautiful. I am talking about butt welding panels such that when finished you can see no evidence of patching welding. Yes, there is finish work required after welding, but it comes down to "how much" finish work.

So that is the goal, undetectable, butt welds. I know what TIG is, and it seems to me that in any butt weld (since you can never get the edges to completely touch perfectly, no matter how accurate your cuts) you will need to use fill metal. So is there a real advantage here with TIG? If I can get my MIG dialed in just right for heat and wire speed, shouldn't I be able to get a nice weld needing little finishing? (by that I mean not having to grind off 70-80% of the metal I just laid down).

I know that TIG will produce a stronger weld, but I don't think that is much of an issue with this body panel work...

SO... I am looking for folks with real TIG and MIG and body panel experience here....

??????????

Wed Jun 18, 2008 1:37 pm

You definitely have greater control with a TIG. It is also much harder to
get the technique down You're using both hands and a foot which can be a bitch when you're laying on your back with the helmet on and sparks
going down your back. I think TIG is better suited to bench/jig type work.
With practice you can make some really nice welds with MIG and they'll
disappear with some flapdisc/ hammer/dolly work.

Wed Jun 18, 2008 1:38 pm

You can do an invisible weld with a mig. You just have to know how to work it right. Check out this thread for the technique:

http://www.metalmeet.com/forum/showthread.php?t=798&highlight=thin+metal+mig

No body filler needed if you do it right.

--louis

Wed Jun 18, 2008 1:59 pm

LouisB wrote: You can do an invisible weld with a mig. You just have to know how to work it right. Check out this thread for the technique:

http://www.metalmeet.com/forum/showthread.php?t=798&highlight=thin+metal+mig

No body filler needed if you do it right.

--louis

Wow, that dude is good. Great tip, I'll have to give that a try...

Wed Jun 18, 2008 5:09 pm

johnshenry wrote: LouisB wrote: You can do an invisible weld with a mig. You just have to know how to work it right. Check out this thread for the technique:

http://www.metalmeet.com/forum/showthread.php?t=798&highlight=thin+metal+mig

No body filler needed if you do it right.

--louis

Wow, that dude is good. Great tip, I'll have to give that a try...

WOW is right!!!!!!

:!: :!: :!:

Thu Jun 19, 2008 9:28 pm

He must be an awfully good welder to butt two pieces of sheet metal together with no gap between them and avoid distortion of the sheet metal and get penetration of the welds. I wish that I could make tack welds that all looked like that.

Thu Jun 19, 2008 11:02 pm

My advice to people that have to grind 70-80% of their work down is to TURN DOWN YOUR WIRE SPEED! And practice. Learn how to control torch speed as well as heat and wire feed if you are doing alot of sheet metal. I tend to be a little slow. If I keep the torch speed up I can control the heat and then dink with wire feed to get some great looking welds that require very little flapper wheel work. Moving too slow is what causes my ugliest work. It is what causes all the grinding in my universe.

Tig is great for the rich and the jobbers. For the hobbiest like my self I think that bread is better spent elsewhere. I have seen the best certified TIG welding done at the brewery where I work. These men are artist. It is just a car. How crazy you get about the restoration and the anal retentiveness involved is up to you.

Take a class at a community college and lean how to use what you already own first. If you cant MIG you sure as hell cant TIG. I know Because I have asked.

Fri Jun 20, 2008 5:29 am

That's Randy Ferguson's beautiful work. Just shows that it is not which welding method you chose, so much as it is whether or not you bump, stretch, smooth, and shrink the metal afterwards. I prefer gas welding to mig, but to each their own.

Randy's metal shaped panels are far better fitting than any patch panel that you are likely to find, but you can still get great results with poor fitting panels by doing some shaping after welding.

A panel without access to both sides presents its own problems, because you cannot stretch the weld shrinkage back out without cutting and removing obstructions and then re-welding.

Campy,

You can make tack welds like that if you have nice clear cover lenses in your welding hood, weld hot and fast, and perhaps bevel the sheet metal edges as I think Randy does. Their is no avoiding distortion from welding, but you can control it. With gas or tig you can make tiny little fusion tacks (no welding rod) that require no grinding at all...maybe a tiny bit of filing.

Hey, John Henry!

John www.ghiaspecialties.com

Fri Jun 20, 2008 6:25 am

John Kelly wrote: That's Randy Ferguson's beautiful work. Just shows that it is not which welding method you chose, so much as it is whether or not you bump, stretch, smooth, and shrink the metal afterwards. I prefer gas welding to mig, but to each their own.

Randy's metal shaped panels are far better fitting than any patch panel that you are likely to find, but you can still get great results with poor fitting panels by doing some shaping after welding.

A panel without access to both sides presents its own problems, because you cannot stretch the weld shrinkage back out without cutting and removing obstructions and then re-welding.

Campy,

You can make tack welds like that if you have nice clear cover lenses in your welding hood, weld hot and fast, and perhaps bevel the sheet metal edges as I think Randy does. Their is no avoiding distortion from welding, but you can control it. With gas or tig you can make tiny little fusion tacks (no welding rod) that require no grinding at all...maybe a tiny bit of filing.

Hey, John Henry!

John www.ghiaspecialties.com

Hey there John. I found one of your posts over on the metalmeet forum, and went to your site to look at you flattening discs. I remember your stuff from way back! NIce to hear from you again.

Ok, the verdict is clear, I'm sticking with my MIG. What I have learned:

Metal heat distorts because it shrinks. It can be hammered back out, and best to do a little at a time. For some reason I always thought it expanded, not shrunk.

For butt welds where you will have to fill a slight gap with steel, MIG is better. TIG will "burn back" the edges instantly.

Forget any kind of continuous weld. Quick over lapping spots works best.

That makes sense. Even if you pulse the trigger at 50% duty cycle doing overlapping welds, you have cut the heat by 50%.

I am guilty in the past of just "guessing" the wire speed and and heat, and lighting up my best panel (and screwing it up). Recently I have got scrap steel and made myself practice. Even if it looks great, I try cutting/adding heat and wire speed to just see what will happen. Also, I try to lay a bead on single piece as flat as I can get it. That is a reference setting that I then use when doing butt welds.

Thanks for all the great tips.

Fri Jun 20, 2008 7:20 am

John Kelly wrote: That's Randy Ferguson's beautiful work. Just shows that it is not which welding method you chose, so much as it is whether or not you bump, stretch, smooth, and shrink the metal afterwards. I prefer gas welding to mig, but to each their own.

Randy's metal shaped panels are far better fitting than any patch panel that you are likely to find, but you can still get great results with poor fitting panels by doing some shaping after welding.

A panel without access to both sides presents its own problems, because you cannot stretch the weld shrinkage back out without cutting and removing obstructions and then re-welding.

Campy,

You can make tack welds like that if you have nice clear cover lenses in your welding hood, weld hot and fast, and perhaps bevel the sheet metal edges as I think Randy does. Their is no avoiding distortion from welding, but you can control it. With gas or tig you can make tiny little fusion tacks (no welding rod) that require no grinding at all...maybe a tiny bit of filing.

Hey, John Henry!

John www.ghiaspecialties.com

Yep John is right, that is Randy Ferguson. If anyone wants to see more of his work, here is his site:

http://fergusoncoachbuilding.com/images/willys_replacement_parts/index.html#frontend

He hand makes replacement panels for Willys. My results are far less spectacular, but I getting better. I also have one of John Kelly's shrinking disks which makes a world of difference in finishing the panel.

--louis

Fri Jun 20, 2008 1:58 pm

I've used a mig welder to weld a lot of panels on four old buses and, for things like left side outer rockers and corner panels, I went back and forth from one side to the other with the tack welds to spread out the heat. If you don't do this, the sheet metal is more likely to get distorted.

Fri Jun 20, 2008 11:10 pm

You know what else is very helpful are those little panel clamps when you're tacking panels together. I got a big pack of them at Harbor Freight for very very little money. Well worth it.

I also agree about heat control. Keep the compressed air gun next to you as you weld. Use the air to cool the weld before the heat can spread, and you'll do a lot to keep the panel cool so it doesn't develop waves. You can get a lot more done too, because you're not waiting for the panel to cool off (or getting impatient and welding on a hot panel). My daughter is now seven and enjoys standing next to daddy, cooling off his welds--I don't even have to stop and fumble for the gun.

John, how old are your kids now?

Sat Jun 21, 2008 7:33 am

My kids are teenagers now, too old and too cool to be hanging around doing anything with daddy..............

Sun Jun 22, 2008 7:09 am

I too, believe that, good results can be achieved with a mig welder.
Here's a link of a project i did last year.
http://www.thesamba.com/vw/forum/viewtopic.php?p=2404726&highlight=#2404726

Sun Jun 22, 2008 7:20 am

slowtwitch wrote: I too, believe that, good results can be achieved with a mig welder.
Here's a link of a project i did last year.
http://www.thesamba.com/vw/forum/viewtopic.php?p=2404726&highlight=#2404726

VERY nice work!

Sun Jun 22, 2008 7:40 am

That is nice work indeed! It is also an example of where gas welding would be a lot faster than mig welding. After tack welding, the parts that were done where you can easily reach both sides could be welded 3"-4" or longer at a time with a torch, then stretched and smoothed with hammer and dolly. It is common to think that you have to go slow and weld small tack welds stitched together to reduce warpage.

This has validity with mig welding, but oxy-acetylene or tig welds can be stretched so easily that longer welds are possible. The metal is moving while you weld it, but once you gain confidence in your metal-finishing skills, this is not a worry. You will know that you can get the contours back, so you will spend less time worrying about warpage, and less time on the overall job as well.

John www.ghiaspecialties.com

Sun Jun 22, 2008 7:45 am

John (or anyone who knows how to gas weld sheetmetal), what kind/size of tip would you use to gas weld. I have an oxy/acet, but I am sure the torch tip is WAY bigger than it needs to be. Would love to experiment with some gas welding if I can just get a new tip for my torch.,...

Sun Jun 22, 2008 8:17 am

Hi John,

I use a 000 tip. Here is an old article I wrote on the subject:

http://metalshapers.org/101/jkelly/index.html

John www.ghiaspecialties.com

Sun Jun 22, 2008 9:57 am

John Kelly wrote: Hi John,

I use a 000 tip. Here is an old article I wrote on the subject:

http://metalshapers.org/101/jkelly/index.html

John www.ghiaspecialties.com

John, I finally got a gas setup and I'm anxious to use it. What rod do you use with gas???? Sorry for the highjack.....

Sun Jun 22, 2008 10:11 am

I use the smallest gas welding welding rod available from the welding supply store. I believe it is coated with copper? for anti-corrosion, and is less than 1/16" thick.

You can also cut a very thin piece of sheet metal and use it for welding rod. If you weld the way I usually do, you actually use very little rod. I mostly melt the pieces of metal together, only dipping a little rod into the molten weld puddle when it gets shallow.

John www.ghiaspecialties.com