Airstream Chassis Replacement

[Dismayed]

I'm interested in buying a vintage Airstream (eventually), but the photos that I've seen of rusted chassis makes me nervous. Then I ran across the Vinstream web site - replacement aluminum chassis and floor system. Has anyone here gone that route? It looks like it might be a good way to get a vintage trailer safely back on the road.

[Dismayed]

bump.

No one here has had Vinstream replace their chassis? I tried calling them to learn more, but I ended up with voice mail.

[markdoane]

There are three possible outcomes:

1. You get lucky and find a trailer with little or no rust (might happen)
2. You find a trailer that needs some repairs that can be done in place without a full monty. Not bad if you have or know a decent welder
3. You need to do a full monty shell-off frame repair. This is major work and only undertake if you have lots of time and money and can acquire the trailer at little cost. If you want to go that route, I would have no hesitation using a Vinstream replacement chassis from what I have read and know about them. They weren't available I when did mine so I went the major repair route with welding done by Ultradog.

[62bam]

Just because it's vintage does not mean it's in a rusty condition. I looked for 6 months throughout the U.S. for a vintage Bambi in good condition, and finally found one only 150 miles away....and it's in excellent shape. The outside needed polish, etc.....bought new tires, and totally redid the interior....now it looks like NEW! Other good ones are still out there...just be patient, and enjoy the process. Good luck!

[Inland RV Center, In]

Originally Posted by Dismayed

I'm interested in buying a vintage Airstream (eventually), but the photos that I've seen of rusted chassis makes me nervous. Then I ran across the Vinstream web site - replacement aluminum chassis and floor system. Has anyone here gone that route? It looks like it might be a good way to get a vintage trailer safely back on the road.

Many years ago, in the late 60's, Southwest Research Institute, in San Antonio, did a research program on an aluminum frame for a travel trailer.

It turned out to be an absolute failure.

Cracks were everywhere, including the A-frame.

Couplers are made of steel only, therefore it was bolted to the A-frame. The bolt holes became oval, since the bolts got loose, even though they were tightened properly.

Bottom line?

A disaster.

I personally saw the chassis, before during and after, as I visited the facility often since I was doing a research program with one of their engineers, to create a small but effective dental pain monitor. The monitor turn out to be good enough, for the US Air Force to publish a project report on it, after their testing it. One of these days, it may be on the market. It's called a "Dolometer".

Andy

[A/SimpleLife]

I too would be interested in hearing more about this replacement chassis and floor system, as I am hoping to buy another vintage trailer. I never quite understood the ice pick method, poking around in the floor of someone's trailer, although it's probably something that just takes experience to know what you're dealing with, and I can't imagine a seller letting you tear the bellypan off to look at the frame when you very well may not buy it. It would be nice to know there was a good option available if you didn't happen to get lucky!

[Dismayed]

"Just because it's vintage does not mean it's in a rusty condition."

True, but there's a higher probability that rust will be a problem.


"Many years ago, in the late 60's, Southwest Research Institute, in San Antonio, did a research program on an aluminum frame for a travel trailer. It turned out to be an absolute failure. Cracks were everywhere, including the A-frame. Couplers are made of steel only, therefore it was bolted to the A-frame. The bolt holes became oval, since the bolts got loose, even though they were tightened properly."

My understanding is that the Vinstream chassis is welded. I'd expect a properly welded aluminum to be quite durable.


"It would be nice to know there was a good option available if you didn't happen to get lucky!"

Absolutely! I'm trying to understand what my options are if major frame work is required. And what it may cost me!

[Inland RV Center, In]

Originally Posted by Dismayed

"Just because it's vintage does not mean it's in a rusty condition."

True, but there's a higher probability that rust will be a problem.


"Many years ago, in the late 60's, Southwest Research Institute, in San Antonio, did a research program on an aluminum frame for a travel trailer. It turned out to be an absolute failure. Cracks were everywhere, including the A-frame. Couplers are made of steel only, therefore it was bolted to the A-frame. The bolt holes became oval, since the bolts got loose, even though they were tightened properly."

My understanding is that the Vinstream chassis is welded. I'd expect a properly welded aluminum to be quite durable.


"It would be nice to know there was a good option available if you didn't happen to get lucky!"

Absolutely! I'm trying to understand what my options are if major frame work is required. And what it may cost me!

The test aluminum chassis at Southwest Research, was welded, very well.

The chassis was a duplicate of the steel chassis that we are all familiar with.

Andy

[truckasaurus]

Most interesting. With the shell off right now I find myself thinking a lot about what I'd try next time, probably a new chassis, maybe not aluminum though.

I've had a sports car with a modular aluminum chassis that was just glued together and that worked just fine. (Lotus) I'm no engineer, yet, but I can see how an aluminum chassis may need to be more boxy and rigid that steel.

I would also find an alternative to the plywood floor or ideally attach it in a different way.

I'm obviously not a purist, I just like the style Airstream created, and that's what I want to retain. If a new chassis makes the project better I'd go that route, but I also recognize that the shell, floor and chassis works together.

[TheBigRedTruck]

Originally Posted by Inland RV Center, In

Many years ago, in the late 60's, Southwest Research Institute, in San Antonio, did a research program on an aluminum frame for a travel trailer.

It turned out to be an absolute failure.

Cracks were everywhere, including the A-frame.

Couplers are made of steel only, therefore it was bolted to the A-frame. The bolt holes became oval, since the bolts got loose, even though they were tightened properly.

Bottom line?

A disaster.

I personally saw the chassis, before during and after, as I visited the facility often since I was doing a research program with one of their engineers, to create a small but effective dental pain monitor. The monitor turn out to be good enough, for the US Air Force to publish a project report on it, after their testing it. One of these days, it may be on the market. It's called a "Dolometer".

Andy

I am not living In the past!!!
A lot has changed In 49 years. Aluminum has come a long way In 49 years!!! Men have walked on the moon, etc and etc!!!
I have a car with a all aluminum frame, Lotus Elise S. Race car hauler made of aluminum!!! It can be done!!!! The real point Is, It would not really save enough weight for the added cost to manufacture!!!
DIMMER

[Dismayed]

Would an aluminum frame really cost that much more to manufacture? Bicycles with aluminum frames are comparable in price to steel-framed bicycles. It is more flexible, though, so larger diameters of tubing are normally used.

Titanium, on the other hand, is very expensive.

[TheBigRedTruck]

Aluminum is not all EQUAL!!! That's why you can find a aluminum bike from $65.00 up to hundreds of dollars!!

Aluminum Alloys

Aluminum Alloys can be divided into nine groups.

Major Alloying Element


1xxx Unalloyed (pure) >99% Al

2xxx Copper is the principal alloying element, though other elements (Magnesium) may be specified

3xxx Manganese is the principal alloying element

4xxx Silicon is the principal alloying element

5xxx Magnesium is the principal alloying element

6xxx Magnesium and Silicon are principal alloying elements

7xxx Zinc is the principal alloying element, but other elements such as Copper, Magnesium, Chromium, and Zirconium may be specified

8xxx Other elements (including Tin and some Lithium compositions)

9xxx Reserved for future use

1xxx Series. These grades of aluminum are characterized by excellent corrosion resistance, high thermal and electrical conductivities, low mechanical properties, and excellent workability. Moderate increases in strength may be obtained by strain hardening. Iron and silicon are the major impurities.
2xxx Series. These alloys require solution heat treatment to obtain optimum properties; in the solution heat-treated condition, mechanical properties are similar to, and sometimes exceed, those of low-carbon steel. In some instances, precipitation heat treatment (aging) is employed to further increase mechanical properties. This treatment increases yield strength, with attendant loss in elongation; its effect on tensile strength is not as great.
The alloys in the 2xxx series do not have as good corrosion resistance as most other aluminum alloys, and under certain conditions they may be subject to intergranular corrosion. Alloys in the 2xxx series are good for parts requiring good strength at temperatures up to 150 °C (300 °F). Except for alloy 2219, these alloys have limited weldability, but some alloys in this series have superior machinability.
3xxx Series. These alloys generally are non-heat treatable but have about 20% more strength than 1xxx series alloys. Because only a limited percentage of manganese (up to about 1.5%) can be effectively added to aluminum, manganese is used as major element in only a few alloys.
4xxx Series. The major alloying element in 4xxx series alloys is silicon, which can be added in sufficient quantities (up to 12%) to cause substantial lowering of the melting range. For this reason, aluminum-silicon alloys are used in welding wire and as brazing alloys for joining aluminum, where a lower melting range than that of the base metal is required. The alloys containing appreciable amounts of silicon become dark gray to charcoal when anodic oxide finishes are applied and hence are in demand for architectural applications.
5xxx Series. The major alloying element is Magnesium an when it is used as a major alloying element or with manganese, the result is a moderate-to-high-strength work-hardenable alloy. Magnesium is considerably more effective than manganese as a hardener, about 0.8% Mg being equal to 1.25% Mn, and it can be added in considerably higher quantities. Alloys in this series possess good welding characteristics and relatively good resistance to corrosion in marine atmospheres. However, limitations should be placed on the amount of cold work and the operating temperatures (150 degrees F) permissible for the higher-magnesium alloys to avoid susceptibility to stress-corrosion cracking.
6xxx Series. Alloys in the 6xxx series contain silicon and magnesium approximately in the proportions required for formation of magnesium silicide (Mg2Si), thus making them heat treatable. Although not as strong as most 2xxx and 7xxx alloys, 6xxx series alloys have good formability, weldability, machinability, and relatively good corrosion resistance, with medium strength. Alloys in this heat-treatable group may be formed in the T4 temper (solution heat treated but not precipitation heat treated) and strengthened after forming to full T6 properties by precipitation heat treatment.
7xxx Series. Zinc, in amounts of 1 to 8% is the major alloying element in 7xxx series alloys, and when coupled with a smaller percentage of magnesium results in heat-treatable alloys of moderate to very high strength. Usually other elements, such as copper and chromium, are also added in small quantities. 7xxx series alloys are used in airframe structures, mobile equipment, and other highly stressed parts. Higher strength 7xxx alloys exhibit reduced resistance to stress corrosion cracking and are often utilized in a slightly overaged temper to provide better combinations of strength, corrosion resistance, and fracture toughness.

[Dismayed]

Thanks, Dimmer. Are you a metallurgist?

[TheBigRedTruck]

I have a degree mechanical engineering. I was a welding insturtur for the United Association of plumber, pipe fitter, sprinkler fitter, steam fitter. So I would say I have a leg to stand on!!!
DIMMER

[VIKING]

It doesn't make sense to me to go through the hassel of an aluminum frame. It can't just be made as a duplicate of a steel one. It would have to be engineered to have the correct strength and durability to use as a replacement for the original frame.
Why not, if you really need to make a new frame, use the same type steel as before, in the same configuration and dimensions, which is a proven design? The problem with these has never been the material type so much as the poor sealing of the chassis area. I took mine apart down to the frame recently and it was apparent that water had been sitting in the bellypan soaking the frame and insulation for years. I was fortunate in that there was really only surface rust on mine though. It seems like the effort could be better spent on things like trying to keep the water out of the bellypan, or directing it out when it does get in. Alternative insulation that won't hold water like a sponge would be an improvement, and as for the flooring itself, How about just wrapping the perimeter of the plywood with thin aluminum like the bellypan material to protect it from moisture which will get on it eventually. The edges and the areas under the shower and toilet are the most prone to water damage so protecting them would add significantly to the possible longevity of a Airstream.
Mine lasted 45 years without any additional improvements over the original construction, so if I can eliminate, to the greatest extent possible, the top five to ten things that go wrong with these, I could have a 100 year old Safari when I'm Just 97, and I might be able to sell it for a profit by then!

Rich

[Inland RV Center, In]

Originally Posted by VIKING

It doesn't make sense to me to go through the hassel of an aluminum frame. It can't just be made as a duplicate of a steel one. It would have to be engineered to have the correct strength and durability to use as a replacement for the original frame.
Why not, if you really need to make a new frame, use the same type steel as before, in the same configuration and dimensions, which is a proven design? The problem with these has never been the material type so much as the poor sealing of the chassis area. I took mine apart down to the frame recently and it was apparent that water had been sitting in the bellypan soaking the frame and insulation for years. I was fortunate in that there was really only surface rust on mine though. It seems like the effort could be better spent on things like trying to keep the water out of the bellypan, or directing it out when it does get in. Alternative insulation that won't hold water like a sponge would be an improvement, and as for the flooring itself, How about just wrapping the perimeter of the plywood with thin aluminum like the bellypan material to protect it from moisture which will get on it eventually. The edges and the areas under the shower and toilet are the most prone to water damage so protecting them would add significantly to the possible longevity of a Airstream.
Mine lasted 45 years without any additional improvements over the original construction, so if I can eliminate, to the greatest extent possible, the top five to ten things that go wrong with these, I could have a 100 year old Safari when I'm Just 97, and I might be able to sell it for a profit by then!

Rich

Rich.

Amen

You nailed it.

My sentiments, exactly.

Monocoque is one thing, semi-monocoque is another.

Andy

[Dismayed]

"It doesn't make sense to me to go through the hassel of an aluminum frame. It can't just be made as a duplicate of a steel one."

Are you afraid to fly? Airplanes use a lot of structural aluminum alloys, but I don't see a lot of them falling from the sky.

Vinstream has already seems to have done the engineering, so why not investigate? I know that Airstream still uses steel frames - and, from what I understand, they under-engineered the frames during the 1970's. So why would I want to simply repair or duplicate a poor frame design? Yes, I know many were properly designed, but there may be better solutions. I'd like to know if there is a lighter stronger option that isn't too expensive. That's all.

"Monocoque is one thing, semi-monocoque is another."

You'll neeed to explain this comment. As far as I understand, using a different frame material in a properly designed frame does not change the design of the trailer.

[VIKING]

Dismayed, I am a person who loves flying. That has nothing to do with my reply and neither does fear. I was presenting another point of view and some reasons for having one.
Don't let anyone here deter you from what you want to do. If it makes you happy to do what you are thinking of then by all means do it.
Don't forget though, that aluminum will deteriorate eventually also. If you don't address the issues that allow water onto your frame you will have the same problem, just a little later. The amount of weight savings couldn't be very significant switching from steel to aluminum. The whole frame is only about 1/5 of the trailer weight, if that. It would be hard to get more than 2 or 3 percent of the trailer weight out of it. On my safari that would be less than one hundred pounds. This is why it's not worth the hassel to me.

This has been, and continues to be, my humble opinion.
Rich

[Ganaraska]

How about a galvanized trailer frame? There is a small manufacturer of utility trailers about 15 miles from here and every trailer they make is galvanized box frame and all.

I'm sure they could build you a galvanized Airstream replacement frame for a price. I would think there are other shops around the country that can do the same.

[Dismayed]

This all started simply because I saw the Vinstream web site and I was curious if anyone had had any experience with them. So it seems no one has had experience with Vinstream. But Dimmer understand aluminum alloys, so I learned something. Other folks have opinions, and that's fine.