The Resurrection of Foam Car - 63 T6B

[merbesfield]

have any of you had any experience with Easy Grind wire, its suppose to be softer than the normal er70s. I've been going to try some but never have. its said to be more malleable than the er70. i'm with Bruce a butt weld with 023 er70 wire then ground down then planished is not a very good or strong weld.
Jay D.

I use L-56. Is this a good wire or not. I too am interested in the easy grind.

PS edit: though I have never noticed any weakness issues with any welds and subsequent grinding as mentioned above. But not like I bend or flex the parts after welding them.

[Phil Planck]

Scott
Very good question and I wish I understood the answer a lot earlier than I finally did. As you can see, there are various opinions and theories on how to properly do a butt weld. The nicest ones I have seen use no filler rod and are gas welded. If I were 20 years younger I would try to perfect that technique. But at 74, too late to learn a new trick, at least on Foam Car.

You will see a dark circle around each tack weld. This is the HAZ(heat affected zone). On long, gas welded butts, this zone will be much wider and should be even in width. This HAZ area has shrunk some, so the planishing(hammere on dolly) is to stretch that metal back out. I have done a lot of reading on the various mig techniques and have settled on this one: Do a series of tack welds to joint the two panels. Planish the tacks. Then grind or file the tacks almost smooth. I like to file on outer metal where possible. If grinding, I use low rpm and try not to get much heat into the tack. I then grind or sand the welds smooth underneath. Then planish again and "feel" the joint and adjacent area for smoothness. Next repeat the process making "oval" tacks next to the first ones. I say oval, because I start next to the first tack, quickly back into the first tack and then reverse direction. This time, I jump around so as not to get the two panels too hot. I wear thin mig welding gloves and if I can feel no, or very little heat at a tack, I will weld next to it. I also have a magnetic copper backing on the back side which helps avoid burn through and lumps underneath. After all of the first series of tacks have been re-tacked adjacent I then planish those tacke, file them down, clean up the underside and planish again. Repeat until all gaps are filled.
Here is the nose piece after 2nd round of tacks and filling almost flush:



When I have finished filling the gaps I will then file the welds flush. I used this technique installing the fender repair piece that Fay Butler made as a Holiday demo. You can barely detect that there is a butt weld.

Regarding brittle welds with mig, that has been challenged and debated. On one of the metal working forums one restorer actually did some test of gas and mig welded butt joints and found very little difference in formabilty due to "hard" welds. I used .023 wire for years. My current spool is .030 and I find very little difference. I use standard mig wire.

I live on dirt roads, so if I ever get Foam Car finished the brittle weld skeptics can follow me and retrieve my NOS nose piece and other patches as they fall off Foam Car as I bounce along. I can take the remaining car to Beverly Hillbillys, and they can write up a great description to sell it.

Phil

[roy mawbey]

Phil,

That last post was good reading. I enjoyed that. No doubt about it this welding lark is all down to experience, I think also, its all about the number of times its gone wrong and you fight yourself, to get the right way of doing it. I suppose its like most things if you have been reading the books and doing it for a long period of time it gets easier by having less mistakes happen.

Us two and 1943 have something in common, we have seen a fair bit of life!

Roy

[Scott B]

Thank you for all of the helpful information and education. Going to try this new approach. Such a dying art - panel beating - shaping - welding - this site is an amazing resource and so interesting to follow along on the projects particularly when we are all working on the same cars.

What would be fascinating sometime Would be to set up a face time to tour our shops or have some of the experts on where the site to do some live tutorials on their projects or facebook live one night. Thank you again for sharing the knowledge on welding. I applied it today to the dimple patch on my floor and made a big difference.

[Phil Planck]

Scott
Forgot to include that I use acetone to clean the weld joints as I tack along.
Phil

[bbspdstr]

Phil wrote: "I live on dirt roads, so if I ever get Foam Car finished the brittle weld skeptics can follow me and retrieve my NOS nose piece and other patches as they fall off Foam Car as I bounce along."

I would rather tend to believe the panels fell off while Foam Sleigh was being pulled by eight tiny reindeer tonight OVER the gravel roads and the bursting of brittle seams was from the overloading of billions of presents.

Merry Christmas,
Bruce the Skeptic

[Phil Planck]

Ref. brittle welds with mig, it is apparently caused by the rapid heat and cooling cycle of mig vs. tig or gas welding. Many tig welders use the same wire used for mig and those welds are more formable. The heat from the mig weld hits the cold adjacent metal and causes the brittleness. I have read that it is good to heat the metal up before mig welding. In this cold weather, even tho I heat my shop when I enter, it takes a while for the metal to warm up. I use a heat gun to warm up the metal in the welding area. Here is a good article if you decide to mig rather than gas weld. It is what my method is based on:

http://fergusoncoachbuilding.blogspot.com/

Randy Ferguson, and almost all pros recommends gas welding or tig, but has shown here the mig can work.

Phil

[roy mawbey]

Phil,

Interesting article by Randy. He made a super job of that butt weld. When I tried that on my door with gas I started off with the tack welds then as I tied to stitch it all together, it then got problematic because I could not effectively find room for a dolly and pure lack off real experience to know what to about that shrinkage.

For sure my repaired panel is still strong using gas and the lead has never moved so unless you opened up the inside of the door section no one would know the pain I went through, except for me.

Interesting though the question of the weld being possibly brittle with MIG if the area is very cold and Tig is possibly a better option. I had never heard of that. I presume the brittle aspect of MIG is only when its used to butt weld panels?

Roy

[bbspdstr]

Roy wrote in reply to Phil: "Interesting though the question of the weld being possibly brittle with MIG if the area is very cold and Tig is possibly a better option. I had never heard of that. I presume the brittle aspect of MIG is only when its used to butt weld panels?"

Yes, yes and yes. We do not throw away the end of a spool of MIG wire (ER70S), we cut it into manageable lengths and use that for TIG butt-welding.

TIG is like an electric version of a gas torch with a hand fed wire covered by an inert gas, so it is like an oxyacetylene gas weld which is, however, without the shielding gas that avoids the oxygen embrittlement. It's just the heat expanding more and cooling more slowly that avoids the rapid absorption of oxygen as in a small border of the added MIG metal.

Unlike a TIG with a post-(weld)-flow, the MIG shuts off it's shielding gas as soon as the trigger is released and the MIG weld, as it quickly cools, draws oxygen into it's perimeter. That's where the embrittlement comes along. Planishing that CAN crack eventually if not immediately. That warning is just that it's a possibility, not always a result.

A MIG weld can be 'normalized' by passing a torch over it. It must be hotter than a heat gun, unless the heat gun can actually reach 1000* and by then, the heat gun would be spreading it's heat in a big area and cause more problems...in sheet metal. Same with Butane or Mapp gas torches. A small oxyacetylene (aircraft) torch works best. Heat and planish. I have never had a crack in an oxyacetylene or TIG or re-heated MIG weld....but I experienced some occasional cracking in over-worked MIG'd areas that I hadn't normalized....and wished I had left a generous overlap and used structural adhesive....

Welding thicker metal also demands pre-heat for a good penetration of MIG or TIG, especially TIG....and you haven't lived until you have welded a roll cage in a Porsche where you hang like a monkey and operate the foot pedal with your knees. Those days are over for me. The only good news it that TIG doesn't shower you with sparks.

Happy New Year,
Bruce

[Phil Planck]

Bruce
You are turning me into a mig skeptic.

Phil

[Phil Planck]

On a different note, I found a complete used T6 harness set on thesamba last week, so between Bruce's donations and this reference/parts set I should be able to finish up my underdash harness repair.


Phil

[Phil Planck]

Finally finished welding in the passenger nose section:



There is a small lower corner that was in bad shape that I had cut out:



It took quite a bit of work to unweld the fender bead and get it out of the way. I then media blasted this area.

Started making a patch piece using the bead roller to get a nice crease line:



Patch has been fitted and ready to weld in. I reworked the old fender area to recreate the nice curve that had disappeared due to accident damage. Made a template of the other side which is original to get the right shape:

[John Pierce]

Welcome back to the North. Has all of your snow melted? Glad to see that you're back at it, Phil.

[Phil Planck]

Thanks John

Little corner section welded in and shaped. Still hate welding upside down. Used Bruce's advice and found a nos political sign wire. Much easier to bend than old heater can rods. Used a tube bender for the tight curve:







Waiting for coatings to dry before joining wire.

[Jack Staggs]

Nice to see you back at it, Phil.