Practically Classics Forum

I shall do. It will be Thursday or Friday as I am off. My parents are staying this weekend so I won't get chance to do very much.

When I used Tig on the landy I found the 50 odd year old birmabright difficult to weld, I have also heard of professionals having similar problems with them, if I was doing it again I would use adhesive to stick a patch on from the rear instead (most modern alloy cars heavily rely on bonding)

I still haven't got round to starting. Unfortunately there are splits in both my rear wings where my rear bumper was riveted to them so I will have to weld those up as a minimum. I then have 3 plug welds to make on each side to attach new brackets. With my rear bumper removed, I can see there are perfectly good (and unused) mounting points behind it which I will use in preference to riveting it back on.

Well, I had a go in the garage earlier (pics are blurry, I will try and clean them up a bit). You need the power pretty high (welding up a crack in my rear wing which is made of 1mm burmabright) to get penetration. My welder is a Clarke 160EN, 6 power settings, I had to have it on 3. For 1mm steel I can use 1 or 2.
To go with that, I had to have the wire speed 2/3 of the way up. normally I weld steel at about 1/4.
The problem is that it penetrated the burmabright too well and you end up with a lump. I am going to grind it back tomorrow and see. 10pm grinding, the noise carries across the fields and the neighbours can hear. I think my solution is going to be to add some 2mm aluminium behind the damage as reinforcement and to (hopefully) make welding up the damage easier.

Sure & the product for which Birmabright were best known is an alloy of Aluminium to two (or is it three? ) parts Magnesium so if you can weld that to itself at all without using the appropriate alloy filler rods (can you get suitable MIG wire for an Al/Mg alloy?) then you've already achieved what some folk take a lifetime to discover they can't do.
If this were Aluminium alone then yes, weld it but unless you're incredibly talented or just plain jammy, I'd be riveting these patches or bonding them as this could become an incredibly frustrating exercise otherwise, without specialised wire.

It appears to be bonding fine. I'll have another poke at it tomorrow and see what happens. Fingers crossed some reinforcement will help spread the heat and stop it melting so quickly.

I wonder if the ally filler is working more like a solder joint than a welded one - if John is right about Birmabright, the edges of the panel may just melt to the filler and not fuse with it.

Life would be so much easier if superglue was really super!

We shall see. if I give it a tug and it cracks down the line behind the "weld" then I will admit defeat and buy some replacement "usable" wings that have no mountings from a breakers i know and panel bonding compound from my local bodyshop.
Then I will "repair" the old wings with a big hammer.

I have a feeling that if anyone can pull this off, it'll be you, Terry since you appear to have a natural talent and a feel for welding that can't be taught, it's something you need to be born with.
Tractorman, if Terry can weld the material with ordinary aluminium wire as I suspect we'll find he can, what'll be happening is that the wire will alloy at the join and the magnesium will flow out so there'll be - in effect - a sea of Birmabright on which the part that flows back along the beach at the turn would be straight aluminium. It would be a weld by definition, but would be rather more brittle than one composed of two identical workpieces and/or one made with wire of a similar alloy. That wouldn't necessarily render it unfit for purpose though, since this isn't a structural repair to an Aluminium bodied car or bike frame we're looking at, but a simple (to someone who has Mr G's enviable talent with the welding gear) patching job on which nobody's life would depend.

I think the worst case scenario if it were to fail is that one of 4 bolts holding the bumper on to that corner (all within 6" of each other) would fall out. Unlike the last person who had the rear bumper off, I'll put the bolts that are currently loose in the mounting bracket actually in to the bumper so it's whole weight isn't swinging from the wings. If the crack starts I'll have to replace the wing. Given I am going to be painting it shortly, it would be quite annoying but not the end of the world.