Body Seam Welding

[gmcconn1]

I wanted to seam weld (TIG preferably) a 1997 Mustang I am working on. I know there is factory sealer between exterior panel to keep water out. But I am looking at front end and underbody structural welding. I am concerned about the coating they dip the entire body in prior to paint at the factory. I can grind the surface but what about the coating between the panels? Is this going to contaminate the welding making it worthless? Will it be impossible to weld?

Anyone insight from people that have done it or know about it is appreciated before I get started...

Thanks

G-

[H80N]

I wanted to seam weld (TIG preferably) a 1997 Mustang I am working on. I know there is factory sealer between exterior panel to keep water out. But I am looking at front end and underbody structural welding. I am concerned about the coating they dip the entire body in prior to paint at the factory. I can grind the surface but what about the coating between the panels? Is this going to contaminate the welding making it worthless? Will it be impossible to weld?

Anyone insight from people that have done it or know about it is appreciated before I get started...

Thanks

G-

Have done it many times over the years... but never done a Mustang.... always ends up being smokey/stinky no matter how much you clean and prep...
expect to spend days cleaning seams with a knot brush and stripper disks..on drills and grinders....welding ends up mostly MIG... lots of seams never get clean enough for TIG.. no matter how hard you try...

Here is Youtube I found by a guy doing it at home..

https://www.youtube.com/watch?v=c8tdGiCW8VU

Am a huge believer in seam welding... having seen many race and street cars after major impacts... here is an old thread on it

http://forum.millerwelds.com/forum/m...ng-plus-a-cage

.

[MMW]

I agree with using mig mostly. If you are stuck on using tig it will need to be very clean for it to work. If you can't get into the seams as described you most likely won't get a good weld. My vote would be clean as best you can & use a mig (not gasless).

One trick I have found where you can't clean all that well is to use very short welds, kind of a start a stop method. The reason for this is at each "stop" the heat affected zone in front of you burns out some of the contaminants before you proceed. If you try to continuous weld a lot of times you over run the cleaning action of the haz.

[H80N]

FWIW.... it seems.... the newer the car the more snot/sealer/adhesive there is ... and the fewer the factory welds...

One trick I have found where you can't clean all that well is to use very short welds, kind of a start a stop method. The reason for this is at each "stop" the heat affected zone in front of you burns out some of the contaminants before you proceed. If you try to continuous weld a lot of times you over run the cleaning action of the haz.

+1 on the skip welding too...

[H80N]

Wire brushes shed bristles.... and the coarse agressive ones you need to clean seams... will break off and stick in your flesh... so I would suggest you wear a quality full face shield to protect your eyes and face

[gmcconn1]

Thanks.

Sounds like MIG is the preferred method so I will start with that.

I worked in body construction engineering for an OEM for a while. We had a project that was having trouble passing crash testing. We ended up running simulations with continuously welded seams instead of spot welds to see what that was worth. ~ 26% improvement over spot welding.

G-

[H80N]

Thanks.

Sounds like MIG is the preferred method so I will start with that.

I worked in body construction engineering for an OEM for a while. We had a project that was having trouble passing crash testing. We ended up running simulations with continuously welded seams instead of spot welds to see what that was worth. ~ 26% improvement over spot welding.

G-

You might consider adding "Gusset Plates" to further tie in the cage to the rest of the structure... should help stiffen the chassis for handling well as provide better crash protection..

https://www.youtube.com/results?search_query=roll+cage+gusset+plates

[ryanjones2150]

any of you guys ever use silicon bronze mig wire for body panel welding? I bought a small spool of it to try on the Bamchero when we were building it, but I just never got around to trying it out. I read a lot of good things about it though.

[H80N]

any of you guys ever use silicon bronze mig wire for body panel welding? I bought a small spool of it to try on the Bamchero when we were building it, but I just never got around to trying it out. I read a lot of good things about it though.

I use it infrequently to TIG on galvanized body panels (Porsche-Audi)....
also periodically to TIG bronze castings

but some folks are really sold on it... here is an article by Ron Covell....

http://metalshapers.org/101/covell/c...ilbronze.shtml

There have been several threads on it here in past years

My preference is steel filler for steel when practical..

[OscarJr]

Thanks.

Sounds like MIG is the preferred method so I will start with that.

I worked in body construction engineering for an OEM for a while. We had a project that was having trouble passing crash testing. We ended up running simulations with continuously welded seams instead of spot welds to see what that was worth. ~ 26% improvement over spot welding.

G-

Good info. Can you tell us what quantitative measurement bettered by 26%?

[H80N]

Here is an interesting approach to Seam/Stitch/Rosette weld a unibody with a MIG welder...

https://www.youtube.com/watch?v=EY0wEKg3dAI

Think I would make my welds longer as well as much more cleaning/prep ...

but this video does give some idea of the areas on the shell that need to be tied together......