What's with the ridgey exterior walls on the Jayco TTs?

tatest wrote:

WoodGlue wrote:

gmw photos wrote:
Woodglue,

Can you tell me how much clamping pressure is applied when utilizing a vacuum bonding procedure ?

Also, can you tell me what the correct clamping pressure and time is for the adhesive that might be in use for these different constructions ?

thanks.

Hi there,

I have those numbers somewhere around here. If I don't post them today, please remind me! I do know that it's oftentimes measured in percentages (%) It also has to do with the type of adhesive being utilized. For instance, Lamilux has their own set numbers.

120 - 130 pounds per square inch is one number I just found. And that's vacuum pressure, not clamping.

WoodGlue

How do you get 8X atmospheric pressure by pulling a vacuum?

Exactly, that maybe pinch rolled but not vacuum. Hek when I calibrate vacuum instruments, I can't even even get to absolute zero. You can get near but it's impossible to get to 0. For those that don't know, absolute zero is the negative barometer reading of the day. Barometer is referenced off of absolute zero where guage pressure/vacuum is referenced off of the atmosphere.

If the barometer of the day is 31 inches of mercury that means that absolute zero is at a vacuum of 31 inches of mercury or at a pressure of -31 inches of mercury. Thus barometer is at a pressure of 31 inches of mercury absolute. 31" of mercury = 15.23 psi . So a vacuum of 15.23 psi is a perfect vacuum. No vacuum greater than this can be achieved. 120 psi is 7.88 times greater than 15.23 psi. ;)

Proteus wrote:


1) Residential construction methods are just that, for homes, not for trailers. And even then, it's mostly for lower end or mid range homes.

I guess it's been too long since I've built a home and maybe I've missed something, but what are the non residential construction methods being used now for homes above lower/mid range?

tatest wrote:
....snip

Most people will argue that their choice of construction technique is the best, even if they don't understand how their RV was made and believe it to be something different that what it really is, because the salesman convinced them.

good point. And watching "fluff" marketing videos cranked out by the manufacturer of any product can sometimes be....misleading. A "well produced" marketing video can be an impressive tool in convincing the uninitiated.
Those of us who have spent several decades working in production environments can often get a few chuckles out of watching marketing videos. I'm happy to be retired from 40 years at a large corporation that has production efficiencies and quality that is industry leading. A lot of good folks and whole lot of fine details in building things that a lot of consumers take for granted.

WoodGlue wrote:

gmw photos wrote:
Woodglue,

Can you tell me how much clamping pressure is applied when utilizing a vacuum bonding procedure ?

Also, can you tell me what the correct clamping pressure and time is for the adhesive that might be in use for these different constructions ?

thanks.

Hi there,

I have those numbers somewhere around here. If I don't post them today, please remind me! I do know that it's oftentimes measured in percentages (%) It also has to do with the type of adhesive being utilized. For instance, Lamilux has their own set numbers.

120 - 130 pounds per square inch is one number I just found. And that's vacuum pressure, not clamping.

WoodGlue

How do you get 8X atmospheric pressure by pulling a vacuum?

The grooves make the aluminum siding stiffer for a given thickness of material, and thinner siding is lighter.

Manufacturers did this also with other materials, including fiberglass before it became practice to laminate the skin to a core, so that the core material stiffened the wall.

There are a lot of different RV manufacturing practices, tradeoffs among cost of materials, labor, and capital equipment for labor-saving and time-saving methods. There are also tradeoffs of strength versus weight.

There are TTs with molded shells, wood frames, aluminum frames. Framed walls can be covered with aluminum or plastic skins, with either framing material. Fiberglass skins can be smooth or have ridges.

Many RVs are built today with no wall framing, rather the skin is laminated to a core, the skin can be aluminum or fiberglass or some other composite, and will most likely be smooth, though when Winnebago first developed the technology they used a corrugated skin. Cores can be different foam materials, or honeycomb or corrugated; foams are popular for insulation.

There are enough options that you don't have to buy ridgey outside walls. Most people will argue that their choice of construction technique is the best, even if they don't understand how their RV was made and believe it to be something different that what it really is, because the salesman convinced them.

Proteus wrote:

Terryallan wrote:

I'd rather drive a truck too. And in truth. No one is going to tow ant TT of any size with a "normal" vehicle. Unless like me. You think a truck IS a normal vehicle. There are only 2 kinds of home owners. Those who have a truck, and those who need a truck. Trucks are needed for WAAAAY more than just towing a RV.

The truck prejudice here is exactly what is wrong with the US RV industry. I don't have a truck. I just safely towed a 6000lb+ trailer for 2k miles through two national parks. Pray tell, what would I want, or need a truck for? If I need to haul a bunch of****** the dump perhaps? I could see it for towing a large 5th wheel, or a full time trailer, but not a standard vacation travel trailer.

Bottom line is there are lots of people in the US, who, like their counterparts in Europe and Australia would like to tow high quality, well designed trailers with efficient and comfortable daily drivers. There just seems to be a lack of high end options out there....

Call me prejudiced then because there is no way in (you no where) that I would ever pull a #6000lb TT of length with a unibody SUV. I grew up in the country and have seen the results of pulling and trying to stop large loads with small/short wheel based vehicles and the results of large loads pushing small vehicles around. I think I will just keep my truck. Glad you are happy with your setup it's just not for me.

WoodGlue wrote:
The time is usually anywhere from 15 minutes to an hour, depending on what kind of adhesive is used in the vacuum process.

Every manufacturer has different tolerances.

I hope this helps

WoodGlue

Yes indeed. It might be better stated that "every manufacturer has different specifications"

The truth of the matter is in the manufacturing and production process there are many details that have to be correct for it all to come together in the end as a finished product that can perform to design specs.

Let's take the example of a wall assembly for a travel trailer. First we would go to the adhesive manufacturer and explain to them what the materials are that we are bonding. They would make a recommendation of what adhesive to use, based on design parameters. Once we have decided on the materials and proper adhesive, the good folks at the adhesive manufacturer would tell us what surface prep, clamping pressure, procedure, time and temperature for correct use of the product.

Guess what ? At the end of the day here....the correct process may involve.....vacuum bonding. Imagine that....a process that is widely used in many industries can very well be the correct method.

Making statements like "vacuum bonding is a EPIC FAIL" is not a correct statement. One needs to know more about what the underlying details are in the parts being manufactured.

Edit: by the way, in case anybody cares, the correct answer to pressure applied in a vacuum bonding scenario is "atmospheric pressure", which is right at 14 pounds per sq inch.

Terryallan wrote:

I'd rather drive a truck too. And in truth. No one is going to tow ant TT of any size with a "normal" vehicle. Unless like me. You think a truck IS a normal vehicle. There are only 2 kinds of home owners. Those who have a truck, and those who need a truck. Trucks are needed for WAAAAY more than just towing a RV.

The truck prejudice here is exactly what is wrong with the US RV industry. I don't have a truck. I just safely towed a 6000lb+ trailer for 2k miles through two national parks. Pray tell, what would I want, or need a truck for? If I need to haul a bunch of****** the dump perhaps? I could see it for towing a large 5th wheel, or a full time trailer, but not a standard vacation travel trailer.

Bottom line is there are lots of people in the US, who, like their counterparts in Europe and Australia would like to tow high quality, well designed trailers with efficient and comfortable daily drivers. There just seems to be a lack of high end options out there....

TxTiger wrote:


1) Residential construction methods are proven and go back much further than the 1950's. I've not seen any laminated/bonded luan/Azdel constructed single/multi-family residenses in my area.

2) Wood does rot if it stays wet. Catch the leak in time and you're ok. Even minor leaks in fiberglass sided trailers can turn them into a money pit to repair if they delam.

3) I own several trucks. Some like my half ton Silverado is a great daily driver and very comfy on trips. It gets over 20 mpg on the road. Not sure what a "normal" vehicle is. A Ford Focus?

1) Residential construction methods are just that, for homes, not for trailers. And even then, it's mostly for lower end or mid range homes.

2) fiberglass trailers only delam if they're made with plywood, not Azdel, composited, etc.

3) to each their own, but you'll never convince me a body on frame truck is a comfortable daily driver, and I've been in a few. Bouncy rides, poor handling, grunting engines just don't do it for me. Oh, and I get 30mpg highway with my diesel SUV :-)

The time is usually anywhere from 15 minutes to an hour, depending on what kind of adhesive is used in the vacuum process.

Every manufacturer has different tolerances.

I hope this helps

WoodGlue