While 6061-T6 alloy is very weldable it has some characteristics that
would make me hesitant to use it to repair a Healey shroud. Its use
in aircraft is due to these same characteristics.
The article on Larry Varley's website describes the original alloy
used in Healeys. Perhaps the closest thing available today, aside
from hunks of discarded shrouds, is 1100 alloy -- in other words
nearly pure aluminum. The shroud material is quite soft, easily
shaped. 1100 alloy is soft, easily shaped and has 35% elongation.
6061-T6 on the other hand is quite hard for aluminum (95 versus 23 on
the Brinell scale), much stronger, not so easily shaped and has 12%
elongation.
The result of welding original shroud material to 6061-T6 might be a
whole lot of distortion as the weld cooled, and over time I would
expect funny things to happen at the weld line. Funny but not
pleasing.
Shaping 6061-T6 to the seductive contours of a Healey shroud could be
challenging. If someone has done it, I would like to hear about how,
what tools, heat, etc.
Numbers presented here are from "Welding Alcoa Aluminum" as published
in 1958.
-Roland
On Sat, 5 Nov 2005 11:16:53 -0600, you wrote:
::Date: Tue, 1 Nov 2005 21:25:17 EST
::From: Gbouff1@aol.com
::Subject: What grade aluminum
::
::Gary, I am in a similar situation although I have not done the repairs yet.
::I checked with some engineering friends of mine in the aircraft business for
::a modern weldable alloy and also asked Roger Menadue many years ago. He was
::Austin-Healey's Chief Engineer.
::
::The advice I got was to use 0.063 inch thick 6061-T6 alloy for the shrouds.
::I remember that I mic'd it and that's the closest sheet thickness that it
::came out to.
::
::TIG welding would work best on it. I had some tears in my rear shroud and
::had it TIG welded and it came out beautifully.
::
::Hope this helps,
::
::Frank Magnusson
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