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Old 01-02-2016, 10:29 PM
Pontiac Power Pontiac Power is offline
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Default What is better -- Oxy welding or Mig welding patch panels for Firebird

Hello Guys,
I am new to this forum and I recently posted a (in general questions) a question about closing the "gills" on a late 60s Firebird.
The consensus is to weld in patch panels vs Shrinking the stamped louvers back to a flat panel
I have access to the option of Oxy or Mig welding. - What is better for strength and ease of finishing. I will be butt welding the patch and plan on practicing on scrap first.

I know fitment and cleanliness is key to any sheetmetal welding. With that in mind my questions are as follows.
First Oxy or Mig?

To butt weld with Oxy the fitment would be no gap - correct? What filler rod would you use?
For mig .023 wire - fitment gap should be 1/2 the wire width - correct.

Is there any strength difference from an Oxy weld vs a Mig weld?
Is there any air contamination issues with Oxy welding?
Does anyone know what gage of metal these late 60s cars used for their quarter panels?
Thanks
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Last edited by Pontiac Power; 01-02-2016 at 10:31 PM. Reason: incomplete
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Old 01-02-2016, 10:36 PM
Pontiac Power Pontiac Power is offline
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Default If mig is preferred - what wire to use.

It was also recommended to me to use ER7OS - 7 wire over OS-6 or OS - 3. Although hard to find it was advised that it was good on penetration with an easier grind then the OS - 6, wire. Planning on .023 - if mig over Oxy - what wire do you recommend?
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Mark
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Old 01-02-2016, 11:32 PM
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Joe Hartson Joe Hartson is offline
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There is a search function on the site use it to research and learn something about what you want to know about. If you still have questions then post them.
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Old 01-03-2016, 01:15 AM
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Type of weld = Oxy
Type of rod = 70s 6 mig wire (used sparingly)
Fit = Tight (scribe not sharpy)
Thickness of metal = 19ga

Allow to come to room temperature, planish, DONE.

Jere
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Old 01-03-2016, 02:49 AM
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mark, if you have access to oxy and are capable (i don't know your background) then having a patch panel fit with no gaps you don't need filler rod. even if you have access to a dc tig it will do the same thing. don't get caught up with numbers on a packet and the ingredients in the welding rod, if it fits perfect, just weld it in no rod. if need be cut some thin strips of a flat sheet, or straighten a steel coat hanger like i was taught to weld back in 84. lol

mig is fine and has its place but using it to weld a patch in the middle of a flat/low crown panel, you will get lots of reasons why not to do it that way.
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Old 01-03-2016, 10:09 AM
sblack sblack is offline
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I second what Neil says. With OA or tig you can really control the heat and you want to use as little heat as possible, which means as little filler as possible and go as fast as you can. That means running the torch/tig at higher heat, which is counter intuitive, but the more time you spend the more heat goes in to the panel and the more distortion you will get. So get a super tight fit, lots of tacks, adjust the 2 panels to be flush with hammer/slapper and dolly after tacking, then go to it.

I have David Gardiner's video where he uses old school OA with no or little filler. I think Peter Tommasini has a youtube video of panel welding. Also there are a lot of good threads on this site.

I know a lot of people use mig and do a lot of grinding but I think it is a lot more work for nothing. I know some craftsmen who call it a manure spreader
The less heat you can do the job with the better, so no filler and going fast is how you minimize heat. And practise, lots of practise. Find the setup that works for you BEFORE you weld on your pride and joy.
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Last edited by sblack; 01-03-2016 at 08:12 PM.
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Old 01-03-2016, 11:46 AM
Pontiac Power Pontiac Power is offline
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Thanks Gentlemen,
Thank you for your input and help. I will practice on a vertical weld with scrap first. I appreciate the candid advise. I will search the topic and watch some videos.
It is great that I asked here because I was thinking MIG all the way - I should have asked here before I purchased a new MIG welder.


Thank you.
Mark
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Old 01-03-2016, 02:07 PM
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red baron red baron is offline
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Mig welder has its time and place.... just like every other form of welding. Don't feel bad about upping your arsenal of equipment to not only get the job done... correctly.... within your skill set.... and timely.
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Old 01-03-2016, 07:28 PM
AllyBill AllyBill is offline
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For those not 100% confident welding in patch repairs there's always the option to roll a joggled border around the patch and put it in with flush rivets. No welding, no distortion, perfectly strong and a very elegant repair scheme that's often overlooked by car restorers while aircraft people do it every day.

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Old 01-03-2016, 08:14 PM
sblack sblack is offline
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Steel Welding with Peter Tommasini is the youtube video I was talking about.
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