Welding Question......

[92GTS-R]

Hi Guys, Well I have purchased a Hobby Mig Welder which has the option to use Gas.  I have purchased a disposable bottle of Argon /CO2 Shielding gas mix.

I'm running 0.8 wire.  I have been  playing around with wire speed and heat settings on some sheet metal but I think I'm now at a good place to actually start work on the car.  Ist Job is to weld in a rectangular patch panel under the rear seat area.  I plan to attempt to butt weld in the panel and then grind down the welds to "almost" smooth.

My question is about seam sealer.  Now once I have finished the welding, do you use the seam sealer direct to the bear metal or do you prime the new metal first, then use the seam sealer?  Also, What paint are you using to cover the newly welded area.  All my welding will be related to the floor pan areas so would like to know the preferred choice of chip proof paints.

Thanks   

 

[Carolina_Mountain_Mustangs]

Even     with your welds  being new you need to clean them with wire brush on drill. Then phosphate the weld & bare metal and then epoxy prime. Ford put the sealer on bare metal but when you do that once the sealer cracks you get rust started on the bare metal. Got to go to Dr. can get you number for the sealer when i get back. If you are inside the car like inside a door or floor i prefer to brush primer on to get into the corners and cracks. If it runs to the outside wipe it off.

 

[92GTS-R]

I don't know what you mean by "Phosphate the weld"  Could you explain, thanks, also (being in the UK) I might not be able to get the exact same paint, so will have to find a brand equivalent     

 

[Fabrice]

@92GTS-R " I have been  playing around with wire speed and heat settings on some sheet metal but I think I'm now at a good place to actually start work on the car. "

Not doubting your fast learning skills and glad to see you go for it! Before you start weld there, know that it's not new clean metal (yes you know that ) and as the floor is set under tension and part of the car strength. The welds need to be strong. not 1/2 strong. Sound obvious but practice showed me that it's not that easy even after hours of practice to be constant.

So I'd really make sure you are indeed ready for that one. Especially using new and old metal to make sure you obtain welds with good penetration. Which means using the right power and wire feed speed and then test/destroy to see how good they were. Also try to reproduce the angle in the car you will need to weld. Welding on vertical surface on your knees is much more difficult than welding 2 pieces on a flat surface from above... You'd be amazed how easy it is to make holes vs close some when you weld new metal to old one. Or the reverse, make nice looking welds that will popup the moment the metal cools off. So If your car needs repairs on the rear lower quarter or doors bottom, I'd start with that instead as its not "that" structural.

Note that I'm nowhere near a good welder myself, and do not want to play the "know better" guy here! See it as a constructive remark based on own experience!
Just trying to tell you that it is structural welds you need there, you are not allowed to  "fu..." them!

Good luck and let us know how that goes! Did you find a place to work btw?
 

 

[92GTS-R]

Here's some pics of some welds I have managed today and the Mig Welder.

 

[92GTS-R]

These are some welds 1st pic top of of sheet,

2nd pic the underside.  So I think I have good Penetration? 

 

[92GTS-R]

@92GTS-R " I have been  playing around with wire speed and heat settings on some sheet metal but I think I'm now at a good place to actually start work on the car. "

Best settings seems to be heat setting 1 and 0.8 wire feed just under 3. using the Argon /Co2 mix.

Good luck and let us know how that goes! Did you find a place to work btw?
No, I'm working on my front drive

 

[Hemikiller]

Welds are decent for a beginner, I've seen MUCH worse. Keep at it and you'll be a pro in short order. Like David said, the key is cleanliness. Phosphating the weld is done using a phosphoric acid based solution to clean the metal and leave a zinc phosphate layer behind. I use Rust Bullet's Metal Blast. 

I'd practice your butt welds before committing to the floor patch. I'd also consider picking up a spool of .025" /.6mm wire and tips. You might find it much easier to use on the gage sheetmetal you'll encounter than the .031/.8mm wire. 

As far as paint, I currently use Rust Bullet on any rusty metal repairs. POR15 is not the same since the company was bought out. 

https://rustbulletuk.com/en/

 

[92GTS-R]

The area I am going to try to weld first is the rectangular (letterbox slot) under the rear seat area.

 

[Fabrice]

Eeeewwwwwww!!! You made worms!!!

Try again connecting 2 plates of old and new metal and have the sheets stand vertically as you will need on the contours of the seats in the car. Worms hate gravity

edit: you posted the pict while I was typing. Do remove ALL the rust before weld both side need be shiny clean. DO NOT USE a grinder as you will reduce the thickness of the old metal even more.

"No, I'm working on my front drive "
Oooh man, I'll think about you when I'll watch the weather on TV!
I did my brakes this weekend and it was a cold experience! Good you will have heat 

 

[Don C]

To answer your question about phosphate, here is what I use, hopefully there is something comparable over there. It can be used on rusted or bare metal.

https://www.amazon.com/Krud-Kutter-Remover-Inhibitor32-Bottle/dp/B0044UP9XU/ref=sr_1_1?crid=TW6PLY68XXKN&dchild=1&keywords=must+for+rust&qid=1606245996&sprefix=Must+fo%2Caps%2C458&sr=8-1

It's good to use after you sand off a section of paint, so you don't have to immediately prime it to prevent flash rust.

 

[Vicus]

If the new welded in section is pure and blank steel, you can try to get Fertan. In general it is a rust converter, but if used on blank steel it covers the surface from getting rusty.

https://www.fertan.co.uk/

It's easy to use and a 0.25 litre bottle it totally enough for a long time. but it is necessary to follow the instructions.

Cheers Frank

 

[92GTS-R]

This is a pic of a piece of the old rusted floor pan and I tried (for fun) to see if I cold join on a piece of new metal.   It Worked!  and the weld is strong!

I Started off with some spot welds then joined them up.

Also tried a couple of butt welds 

 

[Fabrice]

You're a natural m8!

It's been said a few times but one more time:
Make sure the metal is shiny clean before welding on both sides of both sheets, welds on rust or dirt will fail soon or later!

 

[92GTS-R]

I will take my time with the floor pans, doing and finishing 1 quarter at a time. so as not to distort the car frame.

 

[Vicus]

looks good!



I had to do it at the same place but much smaller.



Here you see the dark black parts, covered with the rust converter, and the blank part in the middle, where the rust converter Fertan didn't turn black but brown.



And that's how it looks like after being painted.

 

[turtle5353]

I would recommend getting the old metal much cleaner. I use a 1/4' air angle grinder with 3M  2" roloc grinding wheels in 36 grit for grinding welds down or 50 grit for cleaning old metal.  Your old metal has to be shiny new looking or you will contaminate the weld.  Also you want to ditch the .030 wire and get some .023.  The .030 is too big for sheetmetal work. The heat it takes to properly melt the wire usually will distort or burn through old thin sheet metal. Since it looks like you are running the smaller 140 machine it will definitely benefit you to run the smaller wire.  Do not try to run any beads on sheetmetal. Just a spot weld, then move on, spot weld, move on....... don't get the panels too hot.  On the floor its not as important but on a quarter panel or something like that you dont want to warp the panel.  I even carry a damp rag with me to cool my welds as I go. 

As far as seam sealer goes, you can put it on bare metal if the brand your using says you can. Some say it must be installed over epoxy primer.  I have done it both ways. I usually use Fusor seam sealers. 

Heres a couple pics of the quarter panel Im patching up on a subaru outback.  Make sure you jump around with your spot welds and dont try to run a bead no matter how tempting it is. 

 

[turtle5353]

Also another quick tip, when you strike an arc, start it on the new piece of metal and then whip it over to the the old metal.  The new metal is usually thicker and can take the initial arc of the wire better. 

 

[Bentworker]

I'd second that .030" wire is a little big.  Find some .023"

I have found that compressed air is great to cool the weld.  It minimizes heat distortion and helps keep things clean.  I prefer it over water or a damp rag.

You may also consider finding some copper bar to use as a backer for your butt welds.

Successfully welding gas shielded outdoors is dependent on wind.  You may be able to crank your shielding gas regulator up to help out a bit.  If it isn't still outside I wouldn't weld.

After welding try to remove the excess weld material as skillfully as you can without getting into the base metal.  Consider knocking down your tacks as you go with whatever you are using.  Personally I have found a 36 grit 3M Cubitron 2 disk to cut like butter and produce very little heat.  

Last bit of advice is to trim the ball off the end of the wire between every tack.  Welding sheetmetal with a mig welder usually involves the welder to be set down in the dirt.  With so little voltage to work with starting with fresh cut wire will ensure repeatable arc starts / heat.