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Old 06-07-2017, 09:10 AM   #371
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You can't just cover those jagged edges with rust preventative. They have to be filed and sanded to be rounded and smooth so paint will flow and adhere to form a smooth uniform cover. Paint won't cover jagged edges and so those will rust again. VHB tape instead of a rubber gasket would be much better and keep water from seeping in there in the first place.

Pop top tape appears to be EDPM so shop around for that. You can get it in white which would match better and perhaps not get as hot in the sun. (causing adhesive to get soft)

Can't believe they still use Denim (cotton insulation). That stuff soaks up moisture, stays wet, gets moldy and causes rust. 3M Thinsulate(TM) is the preferred solution for the van industry.
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Old 06-08-2017, 06:33 AM   #372
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Congratulations your van was insulated by the lowest bidder. In this case Mr. Cotton.


"Talk is cheap. Whiskey costs money."
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Old 06-08-2017, 11:14 AM   #373
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There a lot of reasons one might use denim over thinsulate. Many high-end builders use denim, including Advanced RV.
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Old 06-08-2017, 02:14 PM   #374
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Insulation

The SMB build on my van included the "Extreme Weather Insulation" option. Looking at the denim from the outside you are seeing the one layer, looking from the inside (during the build before the walls were installed) reveals the other:

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Old 06-08-2017, 03:35 PM   #375
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Rust Continued

Quote:
Originally Posted by hein View Post
You can't just cover those jagged edges with rust preventative. They have to be filed and sanded to be rounded and smooth so paint will flow and adhere to form a smooth uniform cover. Paint won't cover jagged edges and so those will rust again. VHB tape instead of a rubber gasket would be much better and keep water from seeping in there in the first place.

Pop top tape appears to be EDPM so shop around for that. You can get it in white which would match better and perhaps not get as hot in the sun. (causing adhesive to get soft)

Can't believe they still use Denim (cotton insulation). That stuff soaks up moisture, stays wet, gets moldy and causes rust. 3M Thinsulate(TM) is the preferred solution for the van industry.
hein,

When you refer to Pop Top tape, are you referring to the product SMB sells in their store? https://www.sportsmobilestore.com/pe...otective-tape/
Please clarify, I am not sure how you are proposing to use it.

I agree that the VHB tape would have been a good option to explore to avoid the screw hole penetrations in the first place. It doesn't look like a viable option for those of us with existing penetrations unless we go all the way back to filling the holes, repainting and starting over...

A painter I'm not. I used my Demel where I could and sanded down the painted edges with 400 grit paper before applying the POR-15. I rolled up a small piece of the same 400 grit paper and used it to "swab" the inside of the small fastener penetrations as best I could, then I applied POR-15 inside the small penetration, followed by re-inserting the fastener after dipping it in POR-15. If you have another suggestion please send it my way!

The moisture path behind the attachment in some cases appears to be between the painted surface and the supplied (non-adhesive) gasket. In one case I replaced the gasket with adhesive butyl tape and that appears to be a good solution, in two other cases I am considering either doing the same or caulking the exterior of the fixture as well as the heads of the fasteners where they go into the fixture. My plan is to monitor what I did for a bit and then determine what comes next.

In a previous post (#212) I described the process of sealing up the molding trim retaining clips to prevent rainwater from getting into the panels and wetting the insulation. This is a long-known MB Sprinter design issue (ridiculous that they haven't addressed it), but one that is correctable to prevent exterior water intrusion.
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Old 06-08-2017, 08:29 PM   #376
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Originally Posted by Wrinkledpants View Post
There a lot of reasons one might use denim over thinsulate. Many high-end builders use denim, including Advanced RV.
Denim is cheaper than Thinsulate, but Thinsulate is superior in every other way. Denim is inferior from the POV of biology, chemistry, and physics, all subjects in which I hold teaching credentials.

Biological perspective: Denim is organic in the true definition of the word. IOW, the carbohydrate molecules from which it grew in a living plant will absorb moisture from the atmosphere and it will rot. Bacteria and fungi will begin growing in the stuff and cause it to deteriorate, losing whatever insulative qualities it had. It also becomes a health hazard.

Chemistry perspective: Because denim retains moisture, it acts to promote oxidization of the metal substrate. IOW, it helps induce rust. You can load it with toxic substances to inhibit biological decomposition, but now your walls are full of poison.

Physics perspective: The thermodynamic (heat moving) properties of the two materials are radically different. When wet cotton has a thermal differential between its two sides (cold on one side, hot on the other), the gradient of moisture between the two sides remains constant (water concentration is the same everywhere in the fabric), providing a pathway for thermal conductivity. IOW, heat transfer from the warm side to the cold side is very high. When wet Thinsulate has a thermal differential between its two sides, the electro-chemical properties of Thinsulate cause almost all of the moisture to migrate (wick) to the surface of the colder side. Mathematically, the concentration of water moisture in wet denim is constant while the concentration in Thinsulate is quadratic. The warm side is dry. The lack of moisture maintains the loft of the material and there is no pathway of thermal conductivity for the heat to flow. IOW, it still insulates when moist. Also, because the moisture wicks to the colder side, it evaporates away from the material substrate, causing that fabric to dry out, and to do so quickly.

I worked summers during college and grad school as a wilderness guide, eventually becoming a trainer of new instructors. One of the things I studied in great detail was the insulative properties of different materials. Wet cotton actually refrigerates while wet Thinsulate still keeps a person warm. One of our catchphrases (related to hypothermia) was Wet cotton kills.

There is only one reason anyone would use denim as an insulator. That reason is to save money by using an inferior material.
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Old 06-08-2017, 09:37 PM   #377
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Quote:
Originally Posted by TomH View Post
Denim is cheaper than Thinsulate, but Thinsulate is superior in every other way. Denim is inferior from the POV of biology, chemistry, and physics, all subjects in which I hold teaching credentials.

Biological perspective: Denim is organic in the true definition of the word. IOW, the carbohydrate molecules from which it grew in a living plant will absorb moisture from the atmosphere and it will rot. Bacteria and fungi will begin growing in the stuff and cause it to deteriorate, losing whatever insulative qualities it had. It also becomes a health hazard.

Chemistry perspective: Because denim retains moisture, it acts to promote oxidization of the metal substrate. IOW, it helps induce rust. You can load it with toxic substances to inhibit biological decomposition, but now your walls are full of poison.

Physics perspective: The thermodynamic (heat moving) properties of the two materials are radically different. When wet cotton has a thermal differential between its two sides (cold on one side, hot on the other), the gradient of moisture between the two sides remains constant (water concentration is the same everywhere in the fabric), providing a pathway for thermal conductivity. IOW, heat transfer from the warm side to the cold side is very high. When wet Thinsulate has a thermal differential between its two sides, the electro-chemical properties of Thinsulate cause almost all of the moisture to migrate (wick) to the surface of the colder side. Mathematically, the concentration of water moisture in wet denim is constant while the concentration in Thinsulate is quadratic. The warm side is dry. The lack of moisture maintains the loft of the material and there is no pathway of thermal conductivity for the heat to flow. IOW, it still insulates when moist. Also, because the moisture wicks to the colder side, it evaporates away from the material substrate, causing that fabric to dry out.

There is only one reason anyone would use denim as an insulator. That reason is to save money by using an inferior material.
Thinsulate comes in sheets that you cut shapes out of. There are tons of odd-shaped nooks and crannies that need to be filled in a van. That means you need to cut perfect shapes that allow the thinsulate to lay flat without any bends. Any bend or kink in the thinsulate sheet negates it's R-value (much like down). You're also constrained to the thickness of the sheet of thinsulate you have. Thinsulate sheets can be cut length and width wise, but you can't trim for height. It's also not suggested to layer thinsulate on itself. So, if you have a 5x3x10 are to fill with insulation, you're going to have about a 3" gap between the insulation and metal edges. SM600L is about 1.75" thick, so if you choose to layer it on top of each other, you're not going to fill the entire space. And because thinsulate's R-value is heavily degraded from compression, you need to have the cut edges perfectly aligned to maintain the loft.

Denim, on the other hand, can easily be molded into any shape since it's R-value doesn't really depend on loft. You can easily fill any space with even coverage without much effort. You can also tailor the depth as denim can be cut in all 3 directions. Upfitters use vapor barriers to protect the denim from moisture (which is what's pictured above).

Advanced RV sells their vans for well north of $300k. They're not using denim because it's "cheap." It's really difficult to get the same effective R-value just by using thinsulate. If you don't want to use denim, then you need to use some other insulation with similar compression properties concurrently with thinsulate.

Your explanation is missing a key component: application.
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Old 06-09-2017, 09:14 AM   #378
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Thinsulate SM600L comes in rolls 60" wide. It can be easily cut with larger ordinary scissors like Fiskas. Strips and loose rolls can be pulled or poked into enclosed bulkheads. There is no significant performance loss from compression or folding it. We offer samples for anyone wanting to become more familiar with the material. DIY and professional upfitters who study their materials are choosing Thinsulate(TM).

All the best,
Hein
Impact, Inc.
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Old 06-09-2017, 11:18 AM   #379
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Quote:
Originally Posted by hein View Post
Thinsulate SM600L comes in rolls 60" wide. It can be easily cut with larger ordinary scissors like Fiskas. Strips and loose rolls can be pulled or poked into enclosed bulkheads. There is no significant performance loss from compression or folding it. We offer samples for anyone wanting to become more familiar with the material. DIY and professional upfitters who study their materials are choosing Thinsulate(TM).

All the best,
Hein
Impact, Inc.
54 l 490 5098
Hein at DIYvan.com
You had stated this in another thread:

"I spoke with my 3M rep and asked if there is a performance degradation if the Thinsulate SM600L is not at full thickness. He said there would be some reduction in performance but it would still be better than a thinner (lower grams/sq m) version of the material."

Thinsulate's R-value of 5.2 for SM600L. You can buy R-21 denim that's 5.5" thick. Since it's homogenous, a 2" thick piece of denim would have an R-value of about 7.6. Since you can't cut SM600L in the horizontal plane, you would have to compress it as a double layer to fill some areas, or just accept the R-5.2 single layer?

3M made SM600L as an automotive acoustic insulator. They don't talk about thermal insulation anywhere on their product page, and all their tests are oriented around sound deadening. As far as I can tell, you're the only company selling Thinsulate as thermal insulation to the DIY folks and the upfitters. Are the upfitters you've referenced buying the thinsulate from you, or are they getting it right from 3M? If not from you, where else would one buy SM600L?

http://www.3m.com/3M/en_US/company-u...2659035&rt=rud

I really want to like Thinsulate in this application, but I'm struggling to understand how it does a better job at insulating than denim (or any other common insulator) when it costs substantially more. You keep saying it's made for the automotive community (in other threads), but it's made as acoustic insulation and the OEMs get it right from 3M when they're building a car. Do you have test data of some kind that shows it having a higher R-value when doubled up and compressed slightly?
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Old 06-09-2017, 11:31 AM   #380
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Personally, I prefer 800+ fill-power down,*** ethically sourced from geese raised on organic farms in the Pacific Northwest. Simply blow it into all voids in the van for maximum insulation value at virtually no weight. Only downside is that when it gets wet it's not of much use.

*** I'm kidding.
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