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Rob King

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Posted on Wednesday, March 16, 2005 - 9:02 pm:   

Hi Guys
I am ready to close up the windows that won't be used in my coach. I have seen some posts in the past that suggest using 5052 .080 aluminum. I have a local metal shop man who suggests using 3003 .080. He says the only difference is 5052 is 27K tensile strength and 3003 is 20K tensile strength. He says the 3003 will bend easier and less likely to stress crack than 5052 which is stronger but more brittle. What is or has been your experience? Which did you choose? Thoughts/suggestions. Thanks for your input.

Rob
91 Prevost
John Jewett (Jayjay)

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Posted on Wednesday, March 16, 2005 - 9:51 pm:   

Your dealer is correct, and the 3003 has a more corrosion resistant coating than the 5052. The 3003 will retain a "baseball" mark from the local rug rats though, since it is much softer than the 5052. .080 on a bus should not have any problem with stress cracks, and it would be my choice. Especially since it won't "oil-can" from heat or being bumped by a ladder or thrown ball. ...JJ
Jerry Liebler

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Posted on Wednesday, March 16, 2005 - 10:28 pm:   

Why aluminum? A couple of facts. The windows were glass and certainly wern't structural elements. Many airplanes are built of fiberglass-polyester resin over foam cores. Why not cut polyurethane foam sheet stock to fit the openings, glue it in place and cover with fiberglass & resin. I'm gonna try it 2 layers of glass on outside, 1 on inside. Just need some warmer weather.

Regards
Jerry 4107 1120
Rob King

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Posted on Wednesday, March 16, 2005 - 10:47 pm:   

Hi Jerry
I guess I am somewhatlost. I think I vaguely understand what you're saying. Would like to email you to discuss further if this is viable option. Would you email me or give me you're email so we can "talk" more about this approach???

Rob
skykingrob@hotmail.com
Rob King

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Posted on Wednesday, March 16, 2005 - 10:50 pm:   

Hi JJ
So if I understand you're answer, you think that 3003 that is .080 should do just fine if I choose aluminum. Right?

Rob
TWODOGS (Twodogs)

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Posted on Thursday, March 17, 2005 - 2:28 am:   

16 ga. galvanized metal...had 6 windows cut exactly the size I wanted 100.00
Sojourner (Jjimage)

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Posted on Thursday, March 17, 2005 - 7:27 am:   

INCORRECT alum # 5052 of my pass post regards to inter skin.

CORRECT # is 2024 T3 (sheet metal) Tensile Strength is 70#
Good for both outside & inside.

5052 is because my senior moment...SORRY...Tensile Strength is in 30's

6061-0 to T6 is not good. Tensile Strength is in 18 to 45 ranges.

Sorry for confusion, it was too late to re-edit after an e-mail from friend remind me about 5052.

Common alum # 2024 T3, T4, 6061-T4, T6 and 7075-T6 is what I have used at GM Tech for 26years.

I am going re post w/correct # so anyone have it saved.

Happy retire.

Sojourn for Christ, Jerry
Sojourner (Jjimage)

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Posted on Thursday, March 17, 2005 - 9:17 am:   

Caution; Alum # 3003 at any temper is too soft for structural sheet metal. Tensile strength is less than 30 instead of 2024 T-3 at 70k.

Sojourn for Christ, Jerry
Sojourner (Jjimage)

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Posted on Thursday, March 17, 2005 - 9:42 am:   

J Liebler qoute "The windows were glass and certainly wern't structural elements." unqoute.

Windows are structural, at least four in on each side.
They do similar of diagonal brace or skin.

Ever noticed front windshield squeak making turns. If removed, make a sharp turn with tight string fasten diagonally to two corners of windshield mount. It will break at lean-ward direction! Or sudden stop while in sharp turn.

Which mean to avoid squeaking in front, is to replace rubber windshield's molding & retainer as well side's windows

FWIW

Sojourn for Christ, Jerry
Francis Nelson (Fdnelson)

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Posted on Thursday, March 17, 2005 - 11:30 am:   

Hey Jerry, tried to send you an email, but said your address was no good?
James Maxwell (Jmaxwell)

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Posted on Thursday, March 17, 2005 - 12:02 pm:   

Sorry Sojourner, I have to respectfully disagree that any "glass" windows or windshield is structural, and I have not seen an aluminum window frame that is structural either. Windows are generally "float mounted" into the body framework if installed correctly. The window squeeks because of the clearance fit in old window gaskets and the hard rubber; the glass moving relative to the gasket. True, the framework may move, but the window itself lends nothing to prevent the movement, ergo, the squeek.

Many of the fiberglass stick and staple units on the road tdy. with large windshields suffer from cracked, broken, and dis-lodged windshields due to the insufficient or too much clearance on them when figuring the massive amounts of heat caused expansion and contraction taking place. The glass simply does not withstand the expansion and contraction of the massive amount of surface of the fiberglass.

I have to agree with those advocating sheet metal for these "plugs". Frame it and use Sikaflex if u don't want the rivets. Less expansion and contraction factor to deal with, allowing for a better fit, and if strength is a concern, no alum. will compare.
Russell Barnes (Neoruss)

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Posted on Thursday, March 17, 2005 - 12:38 pm:   

Sorry James,

Your blanket statement included bonded-in windows and windshields. In those cases they do add to the structural rigidity. In the case of frame mounted the effect is much less as you pointed out, however not zero.
gusc

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Posted on Thursday, March 17, 2005 - 11:20 pm:   

I agree with James, a window adding to rigidity does not make it structural. To be structural something normally is subjected to both compression and tension and adds to the overall integrity of the body. Windows on buses do not do this. A missing window will not cause a bus body to deform or break, at least this is true of the monocoque bodies and also any type of framed body. It might spring out of shape under torsional loads but it will spring right back into shape

Newer auto windshields are structural, that is the reason they are glued in and w/s in very new buses may be, I don't know about them, but not so in old buses.
John Jewett (Jayjay)

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Posted on Friday, March 18, 2005 - 1:13 am:   

Rob, my choice would be the 5052 or even better the 2024 T3 aircraft stuff, though it is rather pricey, and usually available only in large sheets to get a decent price. With .080 you won't need too many fasteners due to the basic rigidity of the panel itself. The glass/foam sandwich is good too, but extremely hard to get a really first class smooth finish on. SikaFlex is fine, just use a couple of small pop rivets, or screws to hold the panel in place 'til it sets up. If you use pop rivets, try to get the "blind" or "waterproof" type, then you don't have sealing problems before you paint. Cheers...JJ
Rich International Bus & Parts

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Posted on Friday, March 18, 2005 - 12:49 pm:   

From what I have heard from my converters. I would agree with what JJ has said. 5052 h32 aluminum was what MCI, Eagle & GMC used! Maybe there is a better alloy. I am not aware of the advantages of using it. The 5052 h32 cuts & forms beautifully. We bend it, cut it & curve it every day.

The Sika Flex is a great item to point out. No worrys of expansion & contraction of metal (oilcanning effect), no heating & stretching metal, no worries of paint chipping around rivet heads, smooth clean appearance.

Rich
International Bus & Parts
800-468-5287
Rob King

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Posted on Friday, March 18, 2005 - 9:46 pm:   

Hi All
Lots of good info and as always lots of different opinions. Thanks to all. I did talk to a Prevost engineer and he said (though on the QT) that the factory used 3003 .063 on the window areas and 5052 .080 on the lower skins below the windows. When pricing locally the difference between 3003 and 5052 is about $10 for a 5'x10' sheet or about $2.10 per square foot. The price of 2024 T3 was $5.15 per suqare foot!!
I didn't know the sika flex precluded the need for heating the skins to make them expand in order to get a nice tight look. Is that what you really meant Rich? I have read where it does a real good job of adhesive bonding. It would be really nice to have no rivets but as JJ pointed out I would still have to have a few to hold the panels in place while the glue sets, still a nice touch. Rich I will plan to call you Monday to talk about this more.

Rob
Rich International Bus & Parts

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Posted on Friday, March 18, 2005 - 11:10 pm:   

Sika is great stuff. I was a non-believer when we first started carrying it (11) years ago. Now I do seminars on the stuff..........Prevost glues all of there outer skins on there H-3's & new XLII's with it. We open at 8am Monday. Or you can call me at home 407-886-6881.

Thanks

Rich
Rich International Bus & Parts

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Posted on Friday, March 18, 2005 - 11:14 pm:   

Something else I have learned over the years is that local metal distributors have 14 & 16 foot long metal shears. They can cut your metal to perfect specs with the press of a foot pedal. Sometimes for little to no charge.

Rich
John that newguy

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Posted on Saturday, March 19, 2005 - 7:47 am:   

At "walkercoach.com" they say:

"2. Why do your sides looks like one piece?

The window blank out panels are 1/8” aluminum in 10 ‘x 4’ sections;
or as an option they can be all one sheet.

Our concept blends the butt edges to be almost seamless and we use
Sika Flex adhesives and some rivets. So from a distance the side
does look seamless. On some of our higher end coaches, our walls are
built as one unit with a one piece fiberglass skin.

We install heavy 1/8” (.125) x 4’ x 10’ Aluminum window blank out
Panels; where no windows will go, we reinforce with X pattern 1.75”
thick wall heavy steel tubing as to prepare for bracing of bunks on
walls or similar. We use top quality Sika Flex adhesives with over
1100 PSI strength reinforced with 1/8” thick ¾” rivets hidden under
trim work where they can not be seen."

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