To Arc or to Mig ?

[AUS911SC3]

Hi All, What's the preferred method of welding porsche panels. Is it Arc or Mig. My guess is it's Mig but I prefer Arc as it can be a stronger weld. Would appreciate your thoughts.

[jpnovak]

Body panels? I like MIG when pseudo-spot welding replacement panels. I prefer gas or TIG welding for exterior body panels, like flares, cowl repairs, etc.

ARC typically does not have the level of heat control as other methods. Granted good welders can make due with just about all the techniques and produce good results.

[ossiblue]

IMO, ARC may be too difficult to control the heat/feed, creates too much splatter, and in sheet metal, having a weld that is hard is not an advantage. Mig is easier to control, using a gas shield reduces splatter, but it too produces a hard weld material. Careful regulation of voltage/feed is needed as it's very easy to burn through if you're not careful. Gas welding is often preferred because it produces a much softer weld that allows for easier shaping/finishing, especially on sheet metal butt welds.

[docrodg]

Gas or MIG or TIG, I save Arc for big stuff. IMHO arc is great for things like frames and 1/4" steel, but is not for small stuff. Gas you can control easy with practice and no adjustments needed for voltage/wire feed. A good oxy kit is not expensive and you can use the torch for other things like leading panels, heating nuts, and cooking hot dogs.

[AUS911SC3]

Thanks Guys, great advice

[sc_rufctr]

TIG seems to be the choice of professional restorers but for an amateur at home MIG is the most versatile. And... With the right TIG equipment you can also weld aluminium.

Old school stick arch is great for thicker metal. It's cheap and the results can be very good after grinding and clean up but on thinner car metal it's just a PITA.

[DBDP]

IMO TIG is the only way to weld body panels. The advantages of being able to weld without filler can be highly beneficial. Also being able to control heat and tack so small repeatedly can help avoid panel distortion.

Also, I constantly hear that TIG is hard. I don't buy it. If you can ARC you can TIG with a little practice

[Flieger]

Am I missing something here? Both MIG and TIG welding use arcs.

[DBDP]

Originally Posted by Flieger

Am I missing something here? Both MIG and TIG welding use arcs.

arc=STICK

[Augustus]

IMO TIG is the only way to weld body panels. The advantages of being able to weld without filler can be highly beneficial. Also being able to control heat and tack so small repeatedly can help avoid panel distortion.



Also, I constantly hear that TIG is hard. I don't buy it. If you can ARC you can TIG with a little practice

Tig: I'm not coordinated enough to use both hands. Wish I was.

[Tippy]

TIG is superior to all other welding types mentioned above due to very concentrated heat control when it comes to thin metals. Arc is like a hatchet where TIG is like a scalpel.

TIG is required in aviation for certain repairs due to this.

[Jesse16]

TIG is process A+++, just a tad pricey to have one sitting unused in the garage for us amatuers.

[Carbster]

Save the stick welder to fix your snowplow, mig/tig is the only way to go. distortion from excessive heat will warp panels adding bodywork. You need not be able to weld like a pro for most panel replacementnusing plug welds to replicate spot welds. I used type kelico clamps with drilled holes and huge c-clamps. The work is fun and gratifying so long as the panel is well made and stays true.
Tig is a beautiful thing, it will lay down a weld like an itailian supermodel laying across an Guiletta or something, but the cost of ownership and dual movement scare many. If you can buy borrow or rent a mig, it will do the job well. Practice for a few evenings on scrap metal on importantly old german metal! I cut up and rewelded several VW hoods and deck lids to get my settings just right. Its not rocket science, its just metal, with patience, heat and the right tools you can always out think it.

[Iciclehead]

You can also weld sheet metal with gas, it is actually the preferred way as the resultant weld is soft and can be formed as if it were the original sheet as opposed to MIG which makes for a very hard weld seam. The techniques to do so are not dead easy (MIG is easier) but it is awfully nice to be able to just hammer and dolly the weld seam to reduce or eliminate filler.

There are some good tutorials out there for gas welding, I personally use MIG and gas, the gas for the visible sheet metal when I can get to both sides, MIG otherwise.

Dennis

[Dodge Man]

Originally Posted by Flieger

Am I missing something here? Both MIG and TIG welding use arcs.

Arc or heat(flame), not many other ways to weld "sheet" metal repairs at home. Body panels were carbide tip "clamp arc welded" at the factory and the steel is rather thin as welding goes. As many have stated above a MIG can make an easier weld when replacing body panels. MIG is also excellent for "tacking in place" before TIG. However, be sure to get the proper setting, wire type & thickness so you do not burn thru. Too thick of wire will cause burn thru issues or cold welds and will not give you a good operating window. Go to ED Craig's Weld Reality web site and get the book. TIG can be a big PITA but makes very neat welds. A plasma cutter also makes a good cutting tool with clean removal lines for getting the rust out. MIGs can be purchased that can run on household electrical currents. You can always go tour a restoration shop to get more information and visuals. Best of Luck.

[Charles Freeborn]

Tig is the most precision method. Mig is great for laying down a lot of bead, and stick (you're calling arc) has pretty much no business on any part of a unibody car. Rail frame cars, tractors or trains maybe, but not a Porsche.
I still contend that if you're only going to own one welder get a Oxy-Acetylene set up. It's the most versatile for not only welding and brazing, but for general heating of stuck parts and cutting.
For non-structural body panels brazing is plenty strong, and puts less heat into the parts. With proper heat sinking you can do a full clip with a gas rig. I've done it.
-C

[Oldporsche]

As a substitute welding instructor, my preference would be tig then mig. If you have a dc welder then a tig wand and a shielding gas source is all that you would need. You might look into a cheap spot welder or spot accessory for you welder.

Tig welding allows you to reposition an item where a mig spot or tack weld wont. Mig is a fast freeze process that makes things difficult to move if tacked in place incorrectly.