Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-11-2004, 01:15 PM   #15
New Member
 
Join Date: Feb 2004
Posts: 4
You Guys are amazing,
A picture is worth a million words. Now I know what you mean when you say rib, versus frame, or u channel.
What a help! It's all coming clear now. Now I have no excuses.
I only have soft flooring up to the first rib anyway. And the Smiths Penatrating Epoxy sealer has been repairing things for me for years. I recently did a 500 sq ft deck that was doomed from rot. The epoxy strengthened it and killed the rot, saving my friends about $ 50k for at least 10 years if not longer.
I wonder what grade and number of plys of plywood would be needed to go back with. Using the epoxy would surely give even more stiffness and perhaps allow lighter wieght.
Of course it can be treated and soaked all around prior to install.
Thanks to TC, Toaster, Fitzjo, Jaco, Gerberman, for your excellent drawings and time.
Way Cool-
__________________

__________________
brent-
brentleew is offline   Reply With Quote
Old 02-11-2004, 01:27 PM   #16
Site Team
 
, Minnesota
Join Date: Aug 2003
Posts: 6,940
Images: 59
Floor replacement

I throw this out just for comments.

I'm doing a full floor replacement, so this doesn't apply to partial repairs.
I've almost decided to use 3/4 Structural grade plywood, and mount it lengthwise, rather than across the frame.
Here's the data:

Original 5/8 plywood mounted crosswise- bending stiffness 61,000 lb-in^2/ft width

Proposed 3/4 Stuct1 plyform mounted lengthwise-bending stiffness 247,000 lb-in^2/ft width.

Wouldn't this make the floor about 4 times as stiff as the original?
__________________

__________________
markdoane is offline   Reply With Quote
Old 02-11-2004, 01:54 PM   #17
3 Rivet Member
 
Join Date: Apr 2002
Posts: 184
Images: 55
I've been pondering the floor replacement (body off) for my 56 and have been wondering about the same thing. It would seem like the floor would be stiffer.

I plan to seal the wood with epoxy, and apply fiberglass "tape" around the edges of the plywood (about 3" around on both sides) to help stiffen/strengthen the area where the u/c channel attaches.

I also plan to fiberglass in the door area too as this is the most prone to leakage.

Its a fine line between improvement and overkill, especially when weight is involved!


Tripp
__________________
Tripp is offline   Reply With Quote
Old 02-11-2004, 02:00 PM   #18
uwe
418
 
uwe's Avatar
 
2007 25' Safari FB SE
1958 22' Flying Cloud
1974 29' Ambassador
Yucca Valley , California
Join Date: Jun 2002
Location: 1963 26' Overlander
Posts: 4,767
Images: 41
Send a message via Skype™ to uwe
markdoane,

The question would be, do you want it stiffer than original? Would it put undue stress on other parts designed to benefit from the flex the original design allows?
I believe that the problem with Airsteam floors is not the stiffness, but problems with moisture.
__________________
Uwe
www.area63productions.com
uwe is offline   Reply With Quote
Old 02-11-2004, 02:19 PM   #19
Site Team
 
, Minnesota
Join Date: Aug 2003
Posts: 6,940
Images: 59
Plywood

Uwe,

I agree to completely that water infiltration is what starts the process. Let's assume (for the sake of discussion, I know this is hard to accomplish in the real world) that I was able to prevent water infiltration. I think having a stiffer structure would be an advantage. I can't think of any parts, appliances, or structural elements that benefit from having more flexibility.

Am I missing something?
__________________
markdoane is offline   Reply With Quote
Old 02-11-2004, 02:57 PM   #20
Rivet Master
 
till's Avatar
 
Lisle , Illinois
Join Date: Nov 2003
Posts: 1,270
Images: 108
Blog Entries: 2
The strength of the Airstream design comes from its flexability. By being able to flex as it goes down the road the trialer can take more "abuse". Think of it this way, what will hold up better to a hit, a block of rubber or a block of aluminum? The ruber is flexable and will "bounce back", where as the aluminum is rigid and will dent, deform and eventualy fail. All be it that the rubber will fail over time, but it will take a lot longer.

That said, if you go to 3/4" ply how much more wieght are you adding to bounce around on your axles?? Not to be a downer, but keeping your shell sealed and your running gear balanced will help more with your floor than welding steel plate to the frame. Too stiff of a floor will transfer stress to the next "weak" area in the structure and you wind up chasing other new problems.

I do like the idea of a fiberglassed area by the door to help cope with the moisture that will come in with some one entering and exiting the trailer. A welcome matt helps too.

FWIW I'm on the road to a shell off job this summer.
__________________
Tedd Ill
AIR#3788 TAC IL-10
1967/8 Overlander International Twin w/ bunk/s.
Yes, four kids and two adults in the thing.
Happy wife, happy life.
till is offline   Reply With Quote
Old 02-11-2004, 02:58 PM   #21
3 Rivet Member
 
Join Date: Apr 2002
Posts: 184
Images: 55
Uwe,

Regarding the stiffness, on later models (except some 70's) I would agree that they are stiff enough, but on the 50's models with the extra thin aluminum sheet and frame materials, I think a little more stiffness would be advantageous.

I'm not thinking a lot stiffer, just 15-25% or so. My main concern is the attachment of the u channel to the floor and the skin. I have to add a black tank (mine was a park model) and I am relocating the original heavy pressurized water tank to a under the floor plastic tank. I would like to stiffen the floor to protect the integrity of the trailer after these modifications.

Still, i would like all the suggestions I can get! I might miss something.

Tripp
__________________
Tripp is offline   Reply With Quote
Old 02-11-2004, 03:37 PM   #22
Site Team
 
, Minnesota
Join Date: Aug 2003
Posts: 6,940
Images: 59
stiffness?

Tedd,

I really have to think through your analysis.
I look at the trailer as a composite structure. A very light, but longitudinally stiff body sitting on top of a relatively flexible frame.

As the frame, with all its appendages like tankage, batteries, and refrigerators bouces down the road it wants to flex up and down.

The body tries to resist this flexing because it doesn't want to end up with crinkles in its roof. The place where this fails is where the body and frame come together at the very rear where the stress is most extreme.

I think this is why, if any water gets in to weaken the joint between the body and frame, it fails and we end up with the dreaded rear end sag.

I think the body is much more rigid than the frame, and if the frame and floor were stiffer it would put less stress on the rear joint.

Agree? Disagree?
__________________
markdoane is offline   Reply With Quote
Old 02-11-2004, 05:10 PM   #23
Rivet Master
 
till's Avatar
 
Lisle , Illinois
Join Date: Nov 2003
Posts: 1,270
Images: 108
Blog Entries: 2
Mark,

I agree with what you are saying. That is why later in production the frame was altered. The addition on angle brackets and a cross member under the shell (at the rear section of the frame) to increase the attachment area. This cross member helps to spread the load out over a greater area.

What your saying about the wood rotting out and weakening the whole rear section is very true. Once you have the floor start to go (it is part of the structure) you start having a domino affect with the rear sag as part of the visual signs of a problem. Also the vibration presented by running gear out of wack adds to this problem.
__________________
Tedd Ill
AIR#3788 TAC IL-10
1967/8 Overlander International Twin w/ bunk/s.
Yes, four kids and two adults in the thing.
Happy wife, happy life.
till is offline   Reply With Quote
Old 02-11-2004, 05:19 PM   #24
Site Team
 
, Minnesota
Join Date: Aug 2003
Posts: 6,940
Images: 59
Quote:
Originally posted by till
Mark,

Once you have the floor start to go (it is part of the structure) you start having a domino affect with the rear sag as part of the visual signs of a problem.
Boy, isn't that a fact. I didn't have any rear end separation or outwardly visible sign of a problem. I was just trying to get my blacktank back in operation. Once I looked up under the bellyskin and saw about two inches of wood rot, I knew I was in trouble. The more you look, the more problems you discover.

My advice to any new owners of vintage trailers:

DON'T LOOK!
__________________
markdoane is offline   Reply With Quote
Old 02-11-2004, 07:21 PM   #25
Rivet Master
 
59toaster's Avatar
 
1959 22' Caravanner
Atlanta , Georgia
Join Date: Feb 2003
Posts: 2,197
Images: 22
Here is about 100 pictures of a floor being replaced.

http://www.airstreamphotos.com/photo...500&ppuser=155

If that link doesn't work goto www.airstreamphotos.com and look up "williamhenshall" He's on page 58 of the users listing.

It should all come clear between the pictures and digrams (great as usual) and seeing how it's built as you take it appart.

Step on is remove everything over the area you want to replace. Then pull the walls up the the floor seam where you plan to work too. Get the elevator bolts loose and you can get the bad section out.
__________________
1959 22' Caravanner
1988 R20 454 Suburban.
Atlanta, GA
59toaster is offline   Reply With Quote
Old 02-11-2004, 07:22 PM   #26
Rivet Master
 
59toaster's Avatar
 
1959 22' Caravanner
Atlanta , Georgia
Join Date: Feb 2003
Posts: 2,197
Images: 22
Ohhh yeah!
try to remove that as intact as possible to use as a templete.
__________________
1959 22' Caravanner
1988 R20 454 Suburban.
Atlanta, GA
59toaster is offline   Reply With Quote
Old 02-11-2004, 08:15 PM   #27
Rivet Master
 
LOST , Hawaii
Join Date: Jun 2002
Posts: 2,193
I wonder if turning the floor panels won't concentrate the movement in certain areas. Right now the floor can flex every few feet and spread it fairly evenly across the body and frame. If it can only move every 8 feet it seems like there would be a lot more energy to dissipate at those joints.

John
__________________
74Argosy24MH is offline   Reply With Quote
Old 02-11-2004, 08:29 PM   #28
Rivet Master
 
59toaster's Avatar
 
1959 22' Caravanner
Atlanta , Georgia
Join Date: Feb 2003
Posts: 2,197
Images: 22
Quote:
Originally posted by 74Argosy24MH
I wonder if turning the floor panels won't concentrate the movement in certain areas. Right now the floor can flex every few feet and spread it fairly evenly across the body and frame. If it can only move every 8 feet it seems like there would be a lot more energy to dissipate at those joints.

John

Shouldn't be a problem. The new ones are single sheets of partical I understand. I think it was Pashka that made that discovery when he put down his Cork floor.
__________________

__________________
1959 22' Caravanner
1988 R20 454 Suburban.
Atlanta, GA
59toaster is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:10 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.