Classic Mini: Welding Help??

[scottylord]

Hi all,

I have posted a few threads now, but I need some help as I come to weld the step into my mini.

It took me a lot of time and effort to get the fit as I like. But now I am happy with it.

I have only tacked it in place, and I am wondering how should I go about welding the panel in fully? Shall I use the technique in the practial section "welding thin metal"?? Or any other advice

Please help, I do not want to distort the metal.











Please Help!!!

 

[Nathan]

Maybe you should spot weld it all the way down it wont warp as much + you will be grinding it down.

 

[peterd51]

Hi,

you'd run a very small amount of weld, maybe just a spot as you've done already. Maybe place these next to an existing spot and then move to the next spot and do the same.

So you'd then have a row of new spots with gaps in between...

allow the metal to cool for a few minutes and then do the same again with another set of spots. Eventually you have a continuous run of single spots and you grind it all down with a flap-wheel.

Regards
Peter

 

[malcolm]

If it was me I'd put tacks between the tacks until they are spaced at roughly 1/2 inch. Then grind the tacks flat to make them easier to weld over. Then I'd run a 1/2 inch seam (or the thin metal on-off technique if you keep blowing through) starting and finishing between tacks. Then weld another 1/2 inch somewhere else on the car, then another somewhere else. Let all of that cool, then a few more 1/2 inch runs.

Just spotting would mean cold edges and likely leave pinholes along the weld which would need properly sealing from the reverse before paint.

It won't prevent distortion - you'll need to keep an eye on the panels and maybe encourage them back into shape every now and again. Here's one I did this way. There is distortion, but it's fairly localised to the small lengths of weld rather than across the whole panel.

A heatsink will help.

Also if you weld the wing panel before tacking the bottom (use clamps to hold the bottom in place) the panel has somewhere to move which reduces distortion.

 

[scottylord]

Hi,

Many thanks, do a quick question first, am I going about this the right way? does the photos look like I am doing to right thing before welding?

Are the panels going to distort regardless of what I do?

Cheers

 

[GeorgeB]

Eventually you have a continuous run of single spots and you grind it all down with a flap-wheel.

This sounds good to me. I've some had success with this approach on thin sheet, with an arc welder. As long as all the gaps are closed up as much as possible, will the end result qualify as a 'continuous seam' for MOT purposes? After the seam is ground down, filled very slightly and painted, no MOT tester will know, of course. But if he did know, would it pass, if the joint is within a key structural zone?

 

[Nathan]

You look like your doing it fine. as long as the spot welds weld to each other other wise when you grind it down you will have loads of little holes.

 

[Knipex]

No matter what you do you will have loads of pin holes. Its a problem when joining "spots" together.

Personally I skim the front of all welds with a fibreglass paste (just a very thin layer) to seal the holes and keep it water tight (the fibreglass should be forced into the pin holes by pushing hard when applying the layer) then a rust preventive paint and plenty of seam sealer on the reverse.

Seems to have worked OK so far.

I tried running seams but the distortion can be a pain to get out of the panels.