Hi Mike,
A very common problem there. I had to cut the entire lip off and have
another one fashioned and welded back on. TIG welding with a foot
pedal is the easiest, however it will crack if not done properly. The
old metal doesn't like being welded due to contaminants and corrosion
so be prepared to cut it right back to solid metal and fab up patches.
Wire brush the old metal with a stainless brush or wire wheel till
there is no more corrosion visible. Weld a little, brush a little,
weld... brush... weld. The contamination will come out constantly with
the heat of welding and if it is too much it will affect the weld
strength.
A "Power File" is your best friend for working with ali.
It seems to work best welding downwards and allowing the pool to sag
down while filling it up with filler wire. Then turn it over and
grind/brush out any impurities from the seam and weld from the back
side over where you just welded to ensure it is uniform. The old metal
won't pool nicely like fresh metal- or at least I haven't found a way
of getting it to. If there is a line visible on the back side of the
weld, it will crack there as soon as you dress down the front side. A
bit of practice on old metal will go a long way.
I never got good enough at controlling the heat with a MIG on thin
material and ended up just blowing holes in it.
Andy.
On 7/8/17, Mike Tobin <ahbt71 at gmail.com> wrote:
> I've got a couple-inch gap on the rear shroud at the flange bend. What's
> the best way to deal with it? I'd rather do it myself - just because that's
> how I'm approaching the restoration.
> I've got MIG welder and I closed a couple small tears in the front shroud
> with it. I also fill a small hole by using a copper spoon behind the
> hole. When I was done grinding ithe fixes came out OK. I'm hesitating to
> use the spoon on a hole this size. The metal is also pretty thin there from
> corrosian. I could use fiberglass, I suppose, , but I'd rather not.
>
>
> I've been surprised by the amount of factory-applied filler I've uncovered
> on both shrouds. At first I thought I thought it was damage repair with
> the first owner, but then I noticed that the reverse sides of the shrouds
> showed no sign of trauma - the filler was used not to fill but to shape the
> contour..
>
>
>
> Cheers and Thanks Again,
> Mike Tobin
> Townsend, Montana
>
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