B Pillar Repairs

[SteveRK]

With MOT time looming I knew the B pillars were a bit suspect where they joined the outer sills so time for a thorough investigation.

The N/S B pillar was in remarkably good shape and lulled me into a false sense of hope but onto the O/S what initially looked like a 'local patch required' type repair turned out to be more substantial once the toffee hammer was put to work.

Once I started getting to grips with the corrosion & not knowing the extent of damage I decided to play it safe & weld a small re-enforcing plate on the side of the pillar - I didn't want to get into a situation where the whole pillar might drop albeit I was pretty sure it wouldn't due to it also being spot welded to other parts of the door aperture:

The Problem once I had cut back to sound metal:

Initial repair used 2 plates suitable fabricated and fitted either side of the pillar. I went for metal around 1.7mm thick which made fabricating a lot more effort but a lot easier to weld as the sills are pretty thick steel. Lots of fettling required to get them formed close and tight. Vertical welding and upside down welding is definitely a difficult skill for me to master so I settled for making a series of short blobby, crappy looking welds. Took more time to dress up with the grinder afterwards than the welding itself took - always a good measure as to how good your welding is I guess.

Then the middle piece. This I made in thinner 1.2mm steel as it needed to fit nice and snug. Even more fettling required as I particularly wanted this to be a close fit to keep that MOT failer off the scent:

Anyways it should last a good few years and will be largely hidden by the plastic sill trim. Good experience for me in upside down welding but a long way to go yet before I can lay a continuous bead down

[ThreeSheds]

That's a neat repair!

My B pillars were solidly attached to the floor but not much else, so when I replaced the sill with box-section I did have to position it and then jack it up a couple of mm to lift the middle, but I am not entirely sure if this was the pillar dropping or LR tolerances. In any case, the 'metal' (ahem!) that I took out was definitely not supporting anything so I think that any 'dropping' that occurred would have already taken place on the local speed-bumps.

Good experience for me in upside down welding but a long way to go yet before I can lay a continuous bead down

[caveat]

Below is MY thinking using gas-less MIG. Although I first used MIG years (decades) ago, that was on nice gauge metal on a bench and I have never been taught to weld. Any of the techniques described below may be wrong, but they seem to work for me.

[/caveat]

I don't even try to lay down a continuous bead on thin metal - I am most certainly not a skilled welder and I find that after a run of maybe an inch it will blow through even on the lowest settings. And on low settings I am not happy with the penetration.

On thicker metal (say 2mm plus ) I can do a continuous bead, but I find that the distortion is too high (an early attempt at making a bumper from 4"x2" 3.5mm wall resulted in it being bent like a banana!) so I usually weld in a series of 1" runs, each one mid way between two previous ones.

So what I do for thin metal, (reaching for tin-hat) is to repeatedly do short runs (duration depending on metal thickness) starting the next run as soon as the weld/slag pool from the last run starts to solidify. At the end of one short run, I do not remove the wire from the pool, but I make sure that I start the next run before it completely solidifies.

If I am welding a non-stressed area and the metal is 'a bit thin' then this method may take the form of a series of overlapping spot-welds - each one of less than 1 second duration. On normal thickness (16 gauge?) I find that I can comfortably do about a 10mm run at a time.

For vertical welding I usually go upwards - going downwards with gas-less means that you run into the ever-growing pool of slag and it is difficult to see.

Upside down welding with gas-less is nasty. The amount of spatter and slag is huge and will easily set fire to overalls (ask me how I know!). In this situation I make a pent roof over myself with sheets of plywood so that the spatter rolls away, and I put in ear-plugs since having a ball of near molten metal bouncing around in your ear is not nice (ask me how I know that too!).

Right - let the flames begin!

Roger.

[steve_d]

Right - let the flames begin!

Roger.

A subtle hint, perhaps, that you also managed to set fire to the car.

Steve

[ThreeSheds]

A subtle hint, perhaps, that you also managed to set fire to the car.

Steve

Done that before*, but not to this one - yet

No - what I was meaning was that I was expecting people with genuine welding knowledge to be critical of my ideas...

Rog

*Tell you what - on the occasion that I did set fire to a car while I was under it - and I mean REALLY set fire to a car - it's amazing how much of a headless-chicken I became... I did put it out though and (apart from the smell) there was no irreparable damage. It would be nice if I could have someone fire-watching when I weld, but I just don't have that option I am afraid.

[SteveRK]

I will try that technique of keeping the tip in position after pausing as i usually remove the nozzle completely from the area and then start again - with the result that I get dis-jointed fillets (sounds like a medical condition!) I know what you mean about thin metal, even on mine with the lowest setting it just about copes with 1.2mm but more often than not will burn a hole.

I have a AC/AC voltage transformer that I have tried to lower the voltage into the mig which helps reduce the current but makes the wire feed a bit notchy.

[SteveRK]

Ta for the compliment three-sheds - amazing what a bit of paint does to flatter the repair - it looked ragged before painting.