Eagles International Forum

Ahoy, Eagles,

My Eagle is entirely flush riveted, with 3/16" x 120 deg rivets, holding 0.080" thick aluminum 5052-H32 alloy. It is the stuff that 'black boxes' are made of, and can be flanged 90 deg without cracking. The skin is not flanged, but a lot of other stuff that you make is, so it is good for all around use. Costs less than 6061-t6, which must have a x2t to a x4t bend radius. I have had NO trouble with denting, and I put it on 'hot', at about 130f, and there is NO wrinkling in the heat.

Sounds perfect, yes???? ---- Not quite!!!! Go and look at any big airplane which is riveted, (especially if it has had a lot of cat shots) and you WILL see the rivets. Perhaps not immediately, but you will eventually. My Eagle Bus does. I'm not troubled by that, and decided way back that spot blasting and sanding flush rivets was a LOT easier than working around protruding rivets. Yah, I really need to do a corrosion job and re-paint on my Eagle soon, but not today.

On an earlier post, there was mention of using steel for siding. The idea has some real merit. Work it hot, MIG weld the edges -- always locating the edges on the tubing structure. When cool, it will be absolutely drum tight, and won’t loosen and buckle in hot weather. Since it will be tight, it does not have to be very thick -- say if you use ~~0.040” stock would weigh like 1/8” thick aluminum. Metal creep does not occur on the materials we use and at the loads and temperatures that we see.
The edges and seams will fill with bondo quite nicely, and with a continuous – non-moving – weld seam, should hold just great.
Details of the welding -- If I were to try it, I’d not try to use immense sheets. If the scheme works, comfortable sizes will do just as well. Say -- from the baggage bay longeron to the window line, and several feet long, starting and ending on a member. Gap the adjoining pieces ~~ ½” so there is comfortable room for your weld. Try a 1” weld every 3” while you keep the sheet hot and tight with clamps and magnets. Temp of ~~130f is OK, any higher, and you can get burns). Then go back and finish the welds -- still hot. I believe that the process would be a good bit quicker than rivets.
By the time that you have done three adjoining panels, you will know if you have a winner or a bummer. Not really a very big piece of work to try, and if you are not happy with what you see, chop it off and try something else.
Enjoy /s/ Bob

Bob, Thank you for posting this. I have been thinking about what you have posted it makes good sence with the steel. We can use smaller sheets and do maybe a 1/3 at a time. I am going to try this when I get to that part of the bus.

Good Post Wayne.

I'm thinking about this now as well since I am having no luck finding one large sheet of steel. I am wondering if I were to do a 4' wide x 6' tall sheet placed vertically down the length of the bus. Of course, I would probably have to put in some extra braces to be able to weld at the 4' widths but that is not too bad. If done correctly, I still wouldn't have to worry about rivets. And I could do spot welds at all the braces in between to keep it firmly attached to the framing.

Any downside I haven't thought of? Of course, filling the seams would be just like working on a car I guess.

Dale, Bob and I have been talking about this and I think it could work if you keep the sheet of steel hot while you weld it. I was thinking of using Sikaflex on the inside to hold the steel to the cross braces. If you but it on like caulking at all the joints I don't see why it would not hold the two together also it would leave it a little flexible. Who ever gets to this project first will learn a lot to pass on. At the rate I am going you will be first. If I am not knee deep in alligators I will come out and help you so I can learn.

Good Luck Wayne

You're more than welcome, Wayne! I still plan to have the 'Eagle Raising' for anyone who wants to attend. I just gotta figure out what I am going to do. Don and I have been making plans. Getting the deep pit cleaned out and everything!

Don is tuning up an MCI today so we are getting used to buses being here.

Dale-

Let me know when you're ready for the roof-raising. . .if you give a little notice (a month-or-so), I'll see if Cindy and I can come-up. If nothing else, we make really good fender lizards!

On the topic of siding, we used the Kemlite (fiberglass type) in a single sheet (8 x 40') and did a final trimming once it was up. When we did it, we riveted top, bottom and middle rows--and used Sikaflex on most of the cross braces. The Sikaflex may have been a mistake. I'm not sure if it would have been the same with steel, but the siding is clearly stuck to the braces with the Sikaflex, to the point where it created a ripple and you can see the braces in the ripple (especially with the dark paint). I'm hoping with enough miles and frame twist, the Sikaflex will break loose--so far, it's stuck on there like a bum on a ham sandwich.

Just my two cents worth. . .

Art

Ahoy, Eagles,

I sent the below stuff off to Rusty and Jim a few days ago. As regards gluing the skin with 'something', I used ordinary architectural butyl rubber tape. It behaves about half way between rubber and tar. Sticks like crazy, but drifts. I even used it under the rivet line. I get NO mark-off from the frame members which have only the butyl underneath. I used sheet foam, not spray foam.

On a welded skin, I'd suggest go on 'dry', and then caulk ALL places where the skin and frames come together with ordinary butyl caulk. Because it does 'drift', it won't pull the skin. . (You have all heard horror stories of the spray foam gettng under the skin and moving it).

Anyone wants a copy of my spreadsheet, please email me with your address.

Enjoy /s/ Bob

Ahoy, Wayne, Jim,

Some more ‘midnight oil’ thoughts and some numbers on ‘hot’ steel skin.
Thermal coefficient of steel in the nature of 6.7 *10-6. If you have a +60f sheet of 40” length, it expands 0.016”.
OK, now look at the modulus at 28.6 * 10+6, and IF your frame structure is rigid, when sheet and structure is at the same temp, the sheet is at a stress level of 11,400 psi, and with a sheet of 0.040” thick, the tensile force is 458 lbs/inch. Big numbers ---
Jim, I’ve included a spreadsheet which I wrote years ago. You can do numbers easily on rectangular tube. (Feel free to use it). It shows that the lower longeron of 44” length is only good for 26.2 lbs/in uniform load.
So, the hot-sheet will pull the frame – but not much. Question: will the sheet tend to wrinkle at the node points where diagonals and verticals are located???? I’ve NOT seen this on my -01 Eagle.
Perhaps working the hot steel at about +40 f above the ambient temp would be just about right. Any thoughts on this??
Enjoy /s/ Bob

Man, I wish I understood any of that! When ya'll get it all figured out we'll get together and put the siding on my bus.

On a related note, I got one of my Peninsula windows out today to test fit it into the holes that the previous owner made for them. Just my luck... They don't fit. I wanted to move them anyway so it's alright. On the good side of this coin, I did find out that my windows are indeed dual pane. There is always good news if you look hard enough.

Ahoy, Eagles,

More info --- Friend Alan, who was in the steel business said that you should use STRETCH LEVELED SHEET. He said that not many people know of this product, but that you will have a better result with it. I Googled, and there is info on it.

Enjoy /s/ Bob