Welding inner wing to chassis

[rngDeadeye]

Hi all

I was thinking I'd borrow a spot welder to fix the new inner wings on my Astra to the chassis rails but it's been recommended that I plug-weld instead.

So two questions:

1) would you spot or plug?
2) if you plug, do you drill the hole through the thicker chassis rail and weld to the thinner inner wing through the chassis rail, or weld through the thinner inner wing into the thicker chassis rail?

Oh, and another:

3) the inner wings are currently fixed in place with screws after a week of aligning last year so I'd rather not un-screw them. So how do I only drill through one piece!? Would a metal rule be tough enough to stop a drill bit?

 

[chevy2]

Drill through the thinner and plug weld to the thicker behind,
plug welding is generally done on a higher heat setting,

for a good plug weld snip the ball from the mig wire before each weld,
start the weld in the centre of the material to the back and draw the weldpool out to the edges of the drilled hole

 

[rngDeadeye]

I've got a Clark 135 Turbo welder and have the thinner welding wire fitted. Is this ok or should I go for thicker wire?

I've done some before (still a novice) on the rear inner arches, do they look ok?

 

[rngDeadeye]

What size hole is best?

 

[chevy2]

Stick with 0.6mm wire, you'll get a cleaner start on smaller stuff like plug welds,
About a 6mm hole is enough.

 

[rngDeadeye]

Looks like the original spot-welds were about 1 inch apart. Should I keep the same?

 

[chevy2]

Factory spot welds are often pretty random spaced but yeah about 1 to 1.5" spacing will be adequate.

 

[rikrobson]

you can buy spot weld drills. they have a centre spot and the outer edge cuts. this will cut the hole to plug weld while the two parts are "joined"

 

[rngDeadeye]

you can buy spot weld drills. they have a centre spot and the outer edge cuts. this will cut the hole to plug weld while the two parts are "joined"

Yeah, they're 8mm. I think I've removed about 500 spot welds with one!

 

[rngDeadeye]

Ah, just seen you can buy 6mm too, cheers.

 

[BrokenBiker]

i just centre punch and use a 13mm drill. Works just the same and chamfers the edge

 

[rngDeadeye]

Won't that make it burn away easier?

 

[BrokenBiker]

ive never noticed it, just drill deep enough to break the spot weld when removing. If replacing the panel you already have nice clean metal to weld to because of the chamfer

 

[rngDeadeye]

Oh, you're talking about removing the spotweld.

 

[BrokenBiker]

yeah, but last time i removed a panel(front o/s wing) it was just to gain access and replaced the panel with no problem using the holes i had cut with the 13mm drill. Didn't notice any of the material burning away, got some fairly good welds on it

 

[Windy Miller]

...

3) the inner wings are currently fixed in place with screws after a week of aligning last year so I'd rather not un-screw them. So how do I only drill through one piece!? ...

More to the point, how are you going to clean up the chassis rail prior to welding without removing the inner wings?

 

[rngDeadeye]

More to the point, how are you going to clean up the chassis rail prior to welding without removing the inner wings?

I've already sand blasted and weld-through sprayed the bits that touch the inner wings and the new inner wings were sand blasted and primed with weld-through...

 

[Windy Miller]

Wow! That's a seriously in depth rebuild. More photos needed. Many more!

 

[rngDeadeye]

This is my favourite pic. Took a week of evenings if measuring and clamping and screwing to get everything aligned correctly. The only original part you can see is the door: