properties of aluminum

[smallfry]

Is there a book with just Airstream information? I am wondering specifically about the aluminum skin and the lining of the inside. What is the thickness of the layers? Does a reaction occur between the Al skin(s) and stainless steel - if I replace the original fasteners with SS ones? What chemical solutions will best clean Al? I really enjoyed read about "bucking rivets" - fascinating.

[74Argosy24MH]

If you can't find a book on Airstream construction, look for one on aluminum aircraft history, they are very similar in material and construction and it probably would be easier to find.

The exterior skin off my door was .040 (1974 Argosy mh). The interior is probably about the same but you would have to peel the coating off to measure it. I have been told different thicknesses were used over the years. I used .050 to make a new door skin (I wanted more stiffness than the original) and .063 to make new headlight surrounds and fill my rear window openings (the rear window fillers I considered structural support for the cap, the headlights take a lot of pressure from air at speed).

Stainless fasteners would probably be a source of future problems. A fastener should be softer than the materials it fastens, it should fail first. If it tears out the hole you have a worse repair than if the fastener failed.

If by cleaning you mean polishing the skin, there is a ton of info on this forum about polishing. If you mean chemically for paint or after polishing for clearcoat, standard paint prep solvents work fine.

John

[PeterH-350LE]

When I dismantled some of the exterior skin of my 79MH, I was surprised to find that almost all of the windows and the door were riveted to the skin and not to the ribs. This let me to believe that the interior skin is an important part of the shell integrity.
Some of the window openings were originally cut too big, resulting in some of the rivets being just decoration. They did put tons of vulkem in those places to make sure it would not leak.
It takes about 500 rivets to fasten this ~20' panel.

[74Argosy24MH]

Hey Peter, sort of like the picture below? This was my upper rear drivers window, one of the leaks I am sure had aggravated PO's for years.

I agree with you 100% about the inner skin. I look at the shell as a peice of corugated cardboard; strip one of the outside layers off and it becomes very weak.

Did you find any ribs that were split by windows? I have 1 rib that is really 3 pieces, another that is 2 where window(s) were cut into them. I guess the window adds strength, but would have liked the continous run.

John

[hex]

Page 37 of the 1974 A/S-T/T Service Manual shows all the inside skin as "Aluminum Vinyl Clad .032 (thickness).

It is not said whether the vinyl is taken into consideration as part of the thickness. This would be nice to know.

The roof and outer side-walls are "Aluminum Alclad .032.

Oddly (to me) the 61.5"wide Belly-skin and turn-under-transitions
(22 3/8" wide hips/rocker panels) (from bottom outer side-wall to bellyskin ) are "Aluminum Alclad .024 thickness. I would have thought and hoped a thicker skin would have gone under.

Does anyone know if the term "Alclad" is a brand name? or does it describe something generic?
I assume that it refers to something clad (bonded) to the raw aluminum panel. But what? The plasti-coat most likely? Again I wonder if the "cladding" is considered in the thickness?

[skipj]

If I rember right, Alcad is an Alcoa brand name. I think it's 2 layers of aluminum one alloy for strength with a thin cosmetic layes of pure aluminum for apperance. Don't rember where I read that, sorry.
Skip
89 25' Excella
B-190

[74Argosy24MH]

There is no real need for thicker metal on the belly pan. It only protects, is not a structural element. Any heavier and it would add weight with no real benefit.

John

[Pahaska]

Alclad:
Composite wrought product comprised of an aluminum alloy core having on one or both surfaces a metallurgically bonded aluminum or aluminum alloy coating that is anodic to the core and thus electrochemically protects the core against corrosion.

Also:
Wrought alloys are available as duplex products where one aluminum alloy is bonded to another by rolling or extruding. Where the cladding is anodic and sacrificial to the core alloy, the core alloy identification number carries the prefix Alclad.

[PeterH-350LE]

Originally posted by 74Argosy24MH
......Did you find any ribs that were split by windows? I have 1 rib that is really 3 pieces, another that is 2 where window(s) were cut into them. I guess the window adds strength, but would have liked the continous run.

John

No, John, I didn't find any split vertical ribs, but there were some 'loose' horizontal ribs, which caused a problem upon reassemble, due to not having full access from the inside.

Looks like the same guy was still cutting the window openings in '79.