|
|
06-13-2012, 10:16 AM
|
#21
|
Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
|
The steel frame usually rusts out because of failure of other components. Most of the corrosion on my 30yr old trailer was a result of the bumper plate leak and the bumper compartment that funnels water under the belly skins. Combine this with the wet insulation and you have a corrosion nightmare. Aluminum floors, getting rid of the bumper plate, and anodizing the frame would get rid of 99% of the structural problems that Airstreams suffer from.
Perry
Quote:
Originally Posted by CMSmith
Seems like if Airstream had made the frame out of aluminum as well, that a lot of the issues being dealt with (frame rusting out and causing many other problems) would have never happened. Has anyone replaced a rotting out frame with a newly built aluminum frame? Is there a place to get these from for specific models?
|
|
|
|
06-13-2012, 10:22 AM
|
#22
|
Rivet Master
Currently Looking...
Sioux Falls
, South Dakota
Join Date: Jun 2010
Posts: 2,403
|
If the typical new trailer buyer is a trade up often buyer, there'd be no need for a rustproof frame. If the typical new trailer buyer is a price shopper, there'd be no need for a rustproof frame. The cost/benefit analysis on a . . . say $30,000 upcharge for an all aluminum frame and a boat deck subfloor, takes me way past the typical original owner of a mid price travel trailer.
I notice many Model A Ford frames are still good. I wonder if those frames had been encased with a liner and wrapped up with stinky pink insulation so the frames stayed wet with water, if the Model A frames would have done so well.
I actually think the steel frames would last a LOT longer if they were open and not insulated. It looks to me like the Airstream design itself promotes and enables the floor rot and the frame rust.
So what's the real carefree useful life of a new Airstream? Me thinks it's "0", Zero. I still drive my Chevy pickup that I bought new in 1987 every day and I've had no interruptions of service at all. I changed sparkplugs once. The cab never has leaked. No frame rust damage. (I undercoated it when I bought it.) It's an open frame with a heated cab.
I noticed a difference in steel. Cars like the Model A's were made from all new steel. Later cars like the 70's Datsuns were made from steel made from new and used steel. I seem to remember reading that some new steel is made with a 20% recycled steel content. I'm not sure if the used steel content is an issue. I suspect it is. When rust pops on a car fender that sill has paint on two sides, where'd the rust come from?
|
|
|
06-13-2012, 10:29 AM
|
#23
|
Rivet Master
1981 31' Excella II
New Market
, Alabama
Join Date: Sep 2011
Posts: 6,145
|
I agree with Splitrock it is a design issue not a materials issue.
Perry
|
|
|
06-13-2012, 01:27 PM
|
#24
|
Airstream Newby
1975 25' Tradewind
Florence
, South Carolina
Join Date: Jan 2011
Posts: 176
|
So is there a better insulation to use once a floor is replaced so moisture does not get trapped against the frame?
|
|
|
06-13-2012, 02:26 PM
|
#25
|
Rivet Master
Currently Looking...
Sioux Falls
, South Dakota
Join Date: Jun 2010
Posts: 2,403
|
I don't know the answer. Where I replaced the stinky pinky, I used reflective foil air bubble insulation held up from the bottom with aluminum screen. I added belly skin screened drained holes near the leak points (like the step release slot). In my opinion, the belly pan is most of the problem. With it on, it holds water, all but eliminates air flow, and rusts the steel parts.
With the belly skin removed, the raw plywood floor is exposed to water splash up, ice, and snow in winter tow. I'd rather see a powder coated exposed steel frame under a marine grade deck that's waterproof on both sides. That would be a design change but it shouldn't add $30,000 to the purchase cost.
Are they building a travel trailer or a 4 season park model? I think they're confused.
|
|
|
06-13-2012, 02:58 PM
|
#26
|
Rivet Master
1977 31' Sovereign
1963 26' Overlander
1989 34' Excella
Johnsburg
, Illinois
Join Date: Jul 2005
Posts: 2,944
|
Any design of any product is a compromise of many product properties and widely varied intended usages. Airstream is an American legend. An unique aerodynamically shaped aluminum travel trailer pulled by readily available tow vehicles for fun and adventure. The Airstream management occasionally surveys the marketplace to fine tune the product to meet the prospective customer needs and desires. They balance cost of production vs potential market profit. Most of the frequenters of this forum likely do not represent the average potential Airstream customer target. The class A motorhome business is another unique market that Airstream has decided they can not make a reasonable profit off of for the amount of work they must put forward. Its all business and all about making the most money off the resources you must invest.
|
|
|
06-13-2012, 04:22 PM
|
#27
|
"Cloudsplitter"
2003 25' Classic
Houstatlantavegas
, Malebolgia
Join Date: Jun 2007
Posts: 20,000
|
Quote:
Originally Posted by CMSmith
So is there a better insulation to use once a floor is replaced so moisture does not get trapped against the frame?
|
Don't know for sure how much of an improvement it is, haven't seen any of it yet, but this is what there using on the '13 models.
Bob
__________________
I’m done with ‘adulting’…Let’s go find Bigfoot.
|
|
|
06-13-2012, 06:06 PM
|
#28
|
More than one rivet loose
Currently Looking...
Los Alamos
, New Mexico
Join Date: Feb 2006
Posts: 3,756
|
Quote:
Originally Posted by tpi
Are cracks in aluminum frames repairable thru welding/doublers etc. in a practical manner?
|
NO. Many alloys of Aluminum are not weldable. That is why airplanes are riveted.
__________________
Michelle TAC MT-0
Sarah, Snowball
Looking for a 1962 Flying Cloud
|
|
|
06-13-2012, 06:10 PM
|
#29
|
More than one rivet loose
Currently Looking...
Los Alamos
, New Mexico
Join Date: Feb 2006
Posts: 3,756
|
Quote:
Originally Posted by Chrispate
Ye you can with a specialized welding called TIG tungsten inert gas welding. The toughest to master in my opinion an expensive machines, but possible. Side note the skin in my mind is way to thin to TIG weld comfortably.
|
I personally find TIG easier then Gas welding.
__________________
Michelle TAC MT-0
Sarah, Snowball
Looking for a 1962 Flying Cloud
|
|
|
06-13-2012, 06:14 PM
|
#30
|
More than one rivet loose
Currently Looking...
Los Alamos
, New Mexico
Join Date: Feb 2006
Posts: 3,756
|
Quote:
Originally Posted by perryg114
I agree with Splitrock it is a design issue not a materials issue.
Perry
|
I plugged the opening in the front of the A-frame after spraying copious amounts of corrosion inhibitor.
__________________
Michelle TAC MT-0
Sarah, Snowball
Looking for a 1962 Flying Cloud
|
|
|
06-13-2012, 06:47 PM
|
#31
|
Rivet Master
1977 31' Sovereign
1963 26' Overlander
1989 34' Excella
Johnsburg
, Illinois
Join Date: Jul 2005
Posts: 2,944
|
It is true that some heat treated aluminum alloys can not be welded without destroying their strength. If you went with a welded frame, you would not want to use these alloys. Lots of aluminum airplane frames are made from welded aluminum space frames. The easiest aluminum frame to made would be from aluminum I beams of a weldable alloy. An alternative frame material would be extruded rectangular closed cross section beams. The cross members would be either welded to it or bolted. The cost would certainly be higher that the steel frames that are used now and likely more costly than hot dip galvanizing the current steel frames. The current steel frames are custom made for Airstream by an outside supplier. The galvanizing would be done before they are delivered to Airstream. I imagine that Airstream could make a galvanized frame could be a customer selected option on a special order trailer.
|
|
|
06-13-2012, 06:58 PM
|
#32
|
Rivet Master
1989 34.5' Airstream 345
Saint Petersburg
, Florida
Join Date: Apr 2010
Posts: 1,702
|
I've read here in the forum of those who did a skin-off restoration of their Airstreams using Marine Grade plywood for their floors. In my opinion, has to be a better way to go, and one that I'll be using when I rip up carpet and floors in my Airstream, but first, gotta get rid of that water leak......lol
Thanks, Derek
|
|
|
06-13-2012, 08:58 PM
|
#33
|
Rivet Master
2012 25' FB Flying Cloud
Gig Harbor
, Washington
Join Date: Oct 2011
Posts: 780
|
Dwight. I'm thinking a 6" I beam with a 5/8 web and a 4'" flange. The 4" flange would give you lots of fastening surface and the web in my opinion would be more than what is needed. This is all in my head and I've done no calculations and in all probability I won't.
What about a light weight truss system with knee bracing. With enough money I could design one that would last forever.
I agree that the steel framing being used now is adequate and safe. Thermal diffusion galvanizing would be I think a better process than hot dip if galvanizing is being considered. I could go on and on. But I wont. I really like the ABS foam core flooring idea and think this would be something that could be a practical solution to floor rot problems. Fibreglass would be to expensive.
Dan
__________________
TAC
Hope is not a plan.
|
|
|
06-14-2012, 08:11 AM
|
#34
|
Rivet Master
Airstream Dealer
Corona
, California
Join Date: Feb 2002
Posts: 16,497
|
Another issue facing an all aluminum chassis, is how do you fasten the "steel" coupler to the A-frame?
Andy
|
|
|
06-14-2012, 08:58 AM
|
#35
|
Rivet Master
2012 25' FB Flying Cloud
Gig Harbor
, Washington
Join Date: Oct 2011
Posts: 780
|
Andy, I'm just thinking out loud here. I think the frames are fine. Armchair design I call it.
Dan
__________________
TAC
Hope is not a plan.
|
|
|
06-14-2012, 10:51 AM
|
#36
|
Master of Universe
2008 25' Safari FB SE
Grand Junction
, Colorado
Join Date: Sep 2007
Posts: 12,702
|
I was an engineering major for 2 months until I found it interfered with drinking and I became a social science major. Nonetheless, because I was near engineers, I am qualified to guess the answers.
The OP is concerned with bimetal corrosion, but that is easy to solve by isolating the metals from each other. The change I would consider is strengthening the frame so the subfloor is not part of the structure. Then the subfloor would not have to be as strong and other materials may make more sense. Galvanizing the steel makes sense, but anything that costs more than 50˘ is going to be vetoed unless there's a law requiring it. I suspect the European Union requires it. Canada also has stricter standards than the US on some items (I think they require axles with a higher weight rating, for ex.).
I don't know anything about ABS foam core sheets, but ABS plumbing is kind of brittle and can't withstand high heat well. I don't know what temp range of this ABS, but that has to be considered.
I think the belly pan is designed badly and ours is not sealed along the sides so far as I can see, so water can get in. How they keep it warm in the cold seasons with air leaks along the sides is beyond me. The rivets wear through the holes in the pan in several years. The pan is made up of several sections and the black box in the middle may be where the tanks are; that seems sealed well. The rear pan is where the rivets wear through. They used to design cars this badly and the floor boards rusted out.
There's enough expertise around here that we could build better trailers. An engineer with auto/truck experience would be useful for knowledge of seals because cars and trucks don't leak, the 2 Bobs both were in the auto world and know plenty. Rivets are cool, but maybe outdated. If Wally had design patents, they would probably have expired by now (are Silver Streak or Streamline patents available?). All we need is financing and a desire to work. Could we produce them at competitive prices? That would be the hard part. The brands that have come out lately with green or vaguely familiar exteriors just haven't been what most people on the Forum want. Some are very expensive, or interiors not so cool, or QC suspect. Someday, someone will produce a trailer that is more modern in materials and design while looking something like an Airstream and at a better price. Pontiacs, LaSalles and other brands were once cool, but replaced when they got stuck and customers went elsewhere.
Gene
|
|
|
06-14-2012, 11:26 AM
|
#37
|
Rivet Master
2012 25' FB Flying Cloud
Gig Harbor
, Washington
Join Date: Oct 2011
Posts: 780
|
Gene, I was able to drink and maintain an engineering major for six years. You obviously did not learn to pace yourself. As any good engineering student will tell you scheduling is very important. I think if you would have stuck it out you would have made an excellent engineer. We would have hired you just to write contracts and requests for change orders requiring paying us large sums of money. I eventually became pretty good at this. But you would have excelled.
Dan
__________________
TAC
Hope is not a plan.
|
|
|
06-14-2012, 12:06 PM
|
#38
|
Rivet Master
2002 19' Bambi
Lafayette
, California
Join Date: May 2005
Posts: 1,559
|
I find it interesting that the insulated belly pan of an Airstream is occasionally blamed for frame problems. For example, in this thread, there have been the following remarks:
(1981 Airstream) “water under the belly skins. Combine this with the wet insulation and you have a corrosion nightmare.”
(1976 Airstream) “wrapped up with stinky pink insulation so the frames stayed wet with water…. I added belly skin screened drained holes near the leak points (like the step release slot). In my opinion, the belly pan is most of the problem. With it on, it holds water, all but eliminates air flow, and rusts the steel parts.”
(2008 Airstream).”I think the belly pan is designed badly and ours is not sealed along the sides so far as I can see, so water can get in.”
One reason we bought our Airstream was because of the insulated belly pan. Sure helps when the temperatures go below freezing. Should it be watertight? That is probably impossible because of things like the wheel wells. Is there a solution? I think so.
After having our trailer for about a year, I noticed water trapped in the belly pan. My solution was not to seal everything, but to drill a number of 1/8 inch holes in the belly pan at each point where the pan has a low spot. Since then, water has drained out and the insulation has remained dry.
Even with the holes, the insulated belly pan is still effective in freezing temperatures.
Tim
|
|
|
06-14-2012, 12:27 PM
|
#39
|
Rivet Master
2012 25' FB Flying Cloud
Gig Harbor
, Washington
Join Date: Oct 2011
Posts: 780
|
Tim, that sounds like a reasonable solution. I wonder why they don't do this at the factory. Maybe someone like Inland Andy can comment on this.
Dan
__________________
TAC
Hope is not a plan.
|
|
|
06-14-2012, 12:41 PM
|
#40
|
Rivet Master
Currently Looking...
Sioux Falls
, South Dakota
Join Date: Jun 2010
Posts: 2,403
|
Mine has the pan but I'm not a fan of the pan.
|
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|