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Re: Aluminium welding with a MIG
Posted: Sun Jul 13, 2014 10:07 pm
by TerryG
OK, after several attempts I don't think repairing cracks is possible. One of four things happens.
An aluminium blob forms on one side of the crack
You can "weld" the crack but as soon as you flex the metal slightly, it re-forms in exactly the same place
You blow a hole
The aluminium gets thicker on one side of the crack and refuses to bridge it
On the other hand, replacing the mounting bracket by drilling out the spot welds and welding a new aluminium piece on the back by plug welding, works perfectly.
Tomorrows job, call breakers to find some rear wings from a car that hasn't had a brooklands kit fitted so is not cracked and potentially replace the mounting brackets (which will be broken or missing as they all are)
Re: Aluminium welding with a MIG
Posted: Mon Jul 14, 2014 6:47 pm
by tractorman
Sounds sort of sim8ilar to what I was trying to explain! I had a similar thing happen when I tried to weld what looked like aluminium (I seem to remember it was a coffee percolator) and, in spite of using ample heat, there was a nice pool, but a sudden change to the "base" metal. I put it down to the heat being conducted away too quickly for a good fusion to take place - though I'm sure the main reason was my inability to weld aluminium!
It would be interesting to see how it works with two chunks of "proper" aluminium though...
Re: Aluminium welding with a MIG
Posted: Mon Jul 14, 2014 10:43 pm
by TerryG
I will clamp a couple of bits together tomorrow and upload a pic or two.
Re: Aluminium welding with a MIG
Posted: Mon Jul 14, 2014 10:46 pm
by JPB
Giving up on the Magnesium alloy then? Shame, I was sure you'd crack that one if anyone would. Still, welding aluminium is in itself a thing that some folk never quite manage so it's all good.
Re: Aluminium welding with a MIG
Posted: Mon Jul 14, 2014 11:07 pm
by TerryG
I won't throw the wing away, I will have another go with it but when I am less frustrated.
From experience, when things start getting frustrating it is best to walk away and do something else before you throw the frustrating item or it annoys me so much I leave it for years. I have various bits of burmabright (door skins, wings and a scuttle) which are "scrap" unless I can work out how to do this so it would be a handy thing to do if I can pull it off.
Fortunately I don't find welding steel all that difficult (I am not the tidiest welder in the world but I get the job done) so I will get the floor finished then have another go at the "aluminium".
My new phone arrived today so I have a chance of taking some pics and them still being on the phone when I connect it to my laptop.
As I said before, plug welding seems to be no problem and they are strong welds I can pull hard against them and the burmabright starts to bend with no stress showing on the welds at all so it must be possible. Just not with my current frustration level with it.
Re: Aluminium welding with a MIG
Posted: Tue Jul 15, 2014 8:22 am
by tractorman
I seem to remember they had similar problems on "A Land Rover is Born" - though I think it was TIG welding (by some "expert", who may have just been a friend with a TIG!). I expect it will be on Quest again before too long and I'll see if I can catch the right programme - and stay awake (I usually go to sleep if I watch TV at lunchtime!)
Re: Aluminium welding with a MIG
Posted: Tue Jul 15, 2014 8:30 am
by TerryG
I have the whole series. I think they spot welded it but I will have a quick look tonight.
Re: Aluminium welding with a MIG
Posted: Tue Jul 15, 2014 9:47 pm
by TerryG
Still no pics as my phone is at work (whoops) however, it can be done! I promise pics tomorrow even if I have to get my Nikon out.
I cut out the section with a crack in it (I did this the other day in frustration) to try welding in a 1 1/2" section of new metal.
After the reel sticking AGAIN (If you don't feed a few inches of wire through after you have welded a bit, it sticks to the inside of the copper tip) I had the wire speed all the way up to feed it quickly. Forgetting this I went to weld it in and Robert's your mothers brother.
Mass builds up really quickly which has taken some serious filing back but it is entirely possible to weld aluminium to burmabright

I can pick the wing up and swing it around by the new section so I am fairly sure it is going to stay in place.
I suspect my lack of experience is shining through not realising the wire speed was too low but even with the power all the way up to do chassis welding last year, I didn't have to have the wire speed on 10.
Good news as all 3 breakers I have spoken to with range rovers in for breaking are in worse condition than the one I have. I am still calling around as I would like a spare pair having found how difficult they are to come by (I will have enough spare parts to build another one at this rate)
Re: Aluminium welding with a MIG
Posted: Tue Jul 15, 2014 11:32 pm
by JPB

Well there you go, I figured you'd find a way sooner or later.

Re: Aluminium welding with a MIG
Posted: Wed Jul 16, 2014 9:43 am
by kstrutt1
I found the same with TIG, you had to throw loads of metal at it quickly to avoid a big hole forming, in the end I cut off strips of birmabright from a scrap panel to use, the result was not pretty but it is still holding after 3 years and being hit in an accident.
Kevin