What Aluminum in 1975

[JohnG]

Can anyone say for certain what kind of aluminum was used for the skin in 1975?

I have to replace the roadside lower panel that wraps from below the front wing window to the side of the trailer. Need to know for sectain what type aluminum was used. The service manual does not say, it just says .032 thickness and the size of the panel.

[Happycampers]

John, I just replaced the same part on my Argosy except on the back. I just sniped a piece of the old stuff and went to the metal shop and told them I wanted something close to that size, it worked great, I don't think it really matters what size it is as long as it will bend well to conform to the curve, after it is on nobody knows how thick it is anyway. Marvin

[JohnG]

Thanks Marvin, But I know how thick it is since the manual says it is .032

What I need to know is what type of aluminum I need. Like 2024-T3 Aluminum, which type was used in 1975?

I don't know for sure which type was used and I need to know cause after it is replaced I will be polishing the TT and I want the new area to look the same tone as the rest.

[JohnG]

I wonder why AS dosen't have a technical specifications page on thier website, or do they and I have maybe missed it??? I really need to know which type of aluminum they used on the 75's so I can get it ordered.

[Inland RV Center, In]

John G.

The aluminum used for the 75 models was 2024T3.

All the side and roof sheet were .032 inches thick.

If your going to replace the lower side sheets, then change the thickness to .040, as Airstream has in the later models.

If will give the sheel a little extra strength.

Remember that the type construction is semi-monocouque, which means the shell is "load bearing."

That in it self, suggests beefing up the shell, if you change the lower side sheets.

Andy

[JohnG]

Andy,

Thanks for the info. I would have replaced with .032 so I am glad you pointed out what I should use and the type of aluminum too. I am placing a note in my Service Manual now.

[markdoane]

Originally Posted by Inland RV Center, In

John G.
If your going to replace the lower side sheets, then change the thickness to .040, as Airstream has in the later models.
If will give the sheel a little extra strength.
Andy

I guess I should have asked the question also. Just got my .032" for the lower side sheet today.

[JohnG]

Don,

I'm no metallurgist, but I doubt that .008 difference would be all that critical in terms of strength. I think it goes to the old adage that when doing a repair it should be as strong as the original was and if possible it should be stronger.
At least your repair will be as strong as the original, and possibly stronger when you figure in the metal fatigue factor. There is probably a chart somewhere that will tell you how much stronger one size is over the other, but what I am saying is that I wouldn't sweat .008 in difference.

[markdoane]

Originally Posted by JohnG

Don,

I'm no metallurgist, but I doubt that .008 difference would be all that critical in terms of strength. I think it goes to the old adage that when doing a repair it should be as strong as the original was and if possible it should be stronger.
At least your repair will be as strong as the original, and possibly stronger when you figure in the metal fatigue factor. There is probably a chart somewhere that will tell you how much stronger one size is over the other, but what I am saying is that I wouldn't sweat .008 in difference.

Probably one reason they made the newer models with thicker metal was to compensate for lower tensile strength.
Old 2024-T3 has a yield strength of 45,000 psi
New 3004-H38 has a yield strength of 36,000 psi