Edge to Edge joins on Aluminium body work - it's that T-36 again.

[Gordon_M]

 

 

Got a bit of a technical problem here and could do with some advice.

 

The basic situation is that although the frame and sides on my T-36 Snow tractor cab are steel, the original roof cover and curved corners are aluminium, rivetted to the steel frame. Although 95% of the roof cover is fine, a 2" strip has rotted fairly consistently along the edge of each panel where it is rivetted to the frame, as seen in the first image above. By the time I clean it all back and trim it neatly I'm left with a missing strip of Aluminium about 2" high, as seen on the second image which is across the top of the windscreen frame area - the worst section of the roof. Maybe five or six feet of join to do in total.

 

I've tried Aluminium fabrication before - when I replaced the body on the Sno-Cat I got Argon gas and Aluminium filler wire for the MIG, but franky it was horrible to use and the results were less than ideal although eventually I just made it work.

 

I have the MIG, and can get more Argon (£££) and I have a decent spot welder, though no experience in spot-welding Aluminium. The joins will be very visible on the re-finished cab, so I don't want to just fill it full of pop rivets either.

 

If the rest of the roof was in the same state I'd just strip it and re-sheet it, but there are numerous square yards of perfectly acceptable roof, all fastened with hundreds of solid 3/16" rivets that haven't rotted, so I have to try to make the edge-to-edge joining of the repair sections work first.

 

So, should I spend money and just do a lot of practising with the MIG, or should I use the edge joggler and just try to spot weld ?

 

All sensible advice appreciated, and yes, in the first image that is the mounting for the single taillight, which is on the top left corner of the cab roof - snow must get quite deep....

Edited February 19, 2012 by Gordon_M

[Marmite!!]

Your could try Low Temp Aluminium Brazing/welding. http://durafix.co.uk/

 

Durafix aluminium welding rods are used to repair Aluminium, Al-alloys, Zinc, Pot metals, Die-cast and Kirksite dies. In fact you can use it on almost any non-ferrous metal, except stainless steel. You can use Durafix on dissimiliar metals (copper to aluminium) and even galvanized steel.

 

Plenty of kits about on ebay

[Rangie]

I would err on the side of edge joggling. I find welding older aluminium can be fairly problematic. :undecided:

How about joggling the roof section then use countersunk rivets to let in the new metal and finally a skim of filler to make it invisible on the outside? The snag would be the line of rivets on the inside.....

You could drill the new section and plug weld it with mig to make it invisible as well. Again, electric spot-welding alloy has reduced me to a swearing wreck in the past due to the energy levels involved in welding thicker gauge alloy.

 

A tip an old hand gave me was to butt-weld the two sections in very short tacks, allow to cool and then continue to join the dots in an irregular fashion to minimise distortion. I have found I end up dollying the repair afterwards to remove the worst of the distortion.

 

So yeah, for skins I prefer mechanical fixings, for structures/castings I weld. Just my tuppenceworth

 

Alec.

[Marmite!!]

You could try joggling the endge & bonding it, good enough for cars & aircraft these days!!

 

May be something like this.. http://www.masterbond.com/applications/metal-bonding-adhesives?gclid=CPfMn8nmqa4CFUcTfAodmB80RQ

[Gordon_M]

Thanks for that advice chaps. I'd seen DURAFIX before but hadn't clocked it would do for that sheet metal. I've snapped up an economical kit from E-Bay and will give it a go.

 

I'll keep the mechanical joints as a fallback option - in fact I'll probably joggle the repair section and then DURAFIX the seam on both sides.

 

I could really have used this when making the Sno-Cat roof, but then if I have to do another one I'll be all set.

 

Thanks again

[philhrc]

a ac/dc TIG is really the best thing but £££'s ....

 

before you do anything clean with something like brake cleaner , to make it really clean , and don't touch it afterwards the grease from your hands will contaminate it ....

 

i use the wurth panel bond , 3M do a similar kit but i can't remember the part number , it works very well on non structual areas .. swage it and bond it can be rubbed/sanded down when it's set and is very strong , they use it for bonding roof skins/quater panels on a lot of cars ...

 

[Gordon_M]

Thanks chaps - will report back in due time when I give the DURAFIX a go.

 

I'll joggle the repair panel and DURAFIX it. I can spend the time till it gets here cleaning up the other bits that need the same treatment.

 

Gordon