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scottz
Samba Member
Joined: April 13, 2008
Posts: 477
Location: Bellingham, WA
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 Posted: Thu Jul 27, 2017 10:33 am Post subject: Re: insulation |
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| PDXWesty wrote: |
As a mechanical engineer who does energy modeling and basically designs insulated boxes for a living, the construction of the van renders any amount of insulation that you can install in the wall cavities absolutely useless. It does nothing to keep the van warmer, colder or reduce the amount of heat transfer. The van body is full of "short circuits" of direct metal to metal pathways from interior to exterior that nullifies the insulation effectiveness. Also, the shear magnitude of single pane glass area with respect to solid wall panel area overcomes the insulation effectiveness. There is only about 10% of the van "envelope" that can actually be insulated anyway. I'm not even sure why VW would put it in to begin with.
If you want to understand this theory, Google the following terms:
-thermal break
-effective insulation value
If you were to do actual scientific testing on a van for heat transfer, my educated guess would be that adding insulation behind the cabinets would amount to less than a 1% difference in performance.
Now it may have other benefits for sound absorption, but to install anything for thermal improvement is not beneficial. Argue if you want, but scientific analysis would show no substantial benefit. I would not even replace it if it were my van. I think it causes more harm than good. |
^^^ Good post! |
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Zeitgeist 13
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Joined: March 05, 2009
Posts: 12115
Location: Port Manteau
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| Posted: Thu Jul 27, 2017 10:50 am Post subject: Re: insulation |
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Perhaps I'm on my own here, but my whole purpose of adding "insulation" is entirely for sound absorption. I definitely have no interest in keeping heat in; quite the opposite in fact.
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'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
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scottz
Samba Member
Joined: April 13, 2008
Posts: 477
Location: Bellingham, WA
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| Posted: Thu Jul 27, 2017 10:59 am Post subject: Re: insulation |
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| Zeitgeist 13 wrote: |
| Perhaps I'm on my own here, but my whole purpose of adding "insulation" is entirely for sound absorption. I definitely have no interest in keeping heat in; quite the opposite in fact. |
Insulation does not really do a good job of sound attenuation.
Dynamat and similar products reduce sound by reducing resonance. |
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Zeitgeist 13
Samba Member
Joined: March 05, 2009
Posts: 12115
Location: Port Manteau
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| Posted: Thu Jul 27, 2017 11:05 am Post subject: Re: insulation |
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Agreed, which is why I air-quoted the word "insulation".
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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scottz
Samba Member
Joined: April 13, 2008
Posts: 477
Location: Bellingham, WA
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| Posted: Thu Jul 27, 2017 11:32 am Post subject: Re: insulation |
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| PDXWesty wrote: |
| scottz wrote: |
I feel that the radiant barrier between me and the cold, metal outside wall of the van is the most reasonable approach. You are simply trying to reduce the amount of body heat that radiates towards cold surfaces.
Just my 2 cents... |
This is important for comfort. A barrier between exposed cold metal and glass surfaces will make you "feel" more comfortable by reducing the radiation effect. Thermal insulation to reduce heat transfer is futile. |
Agreed. Especially if you are ventilating and you should. That is a small amount of air in that metal box. |
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joetiger 
Samba Member
Joined: January 27, 2005
Posts: 5076
Location: denver
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| Posted: Thu Jul 27, 2017 11:51 am Post subject: Re: insulation |
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So which is better for sound absorption? Dynamat/Fatmat or 3M™ Thinsulate™ Acoustic Insulation SM600L?
I have Fatmat in my van in several spots (adhering to the 25% rule as opposed to full coverage) and after recently driving a Vanagon with zero sound insulation, I can attest to the fact that Fatmat makes a very noticeable difference. I'm intrigued by the 3M stuff, though.
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Joe T.
'86 NAHT Vanagon GL Syncro/ supercharged ABA 2.0 "Pigpen"
'04 GTI 1.8T
'04 Golf R32
"get metaphysical with it. if it's simply a means to get to and from places, it will let you down. if it becomes your zen, it can't fail you." -dabaron
"Still, it's good to be afield."--VWagabond
Available Now! Vanagon to Louisiana--A Two-Lane Reckoning Through Past and Present
www.josephtrussell.com |
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Merian
Samba Member
Joined: January 04, 2014
Posts: 5212
Location: Orygun
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| Posted: Thu Jul 27, 2017 12:01 pm Post subject: Re: insulation |
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| PDXWesty wrote: |
This is important for comfort. A barrier between exposed cold metal and glass surfaces will make you "feel" more comfortable by reducing the radiation effect. Thermal insulation to reduce heat transfer is futile. |
obviously if it reduces radiant heat exchange, "the radiation effect" then it will function to reduce heat transfer
the windows are an issue - without question but in no way is it "futile" to add insulation
but, do the calculations if you wish and post them - I have copies of Kreith as well as Karlekar and Desmond so feel free to use their tables
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scottz
Samba Member
Joined: April 13, 2008
Posts: 477
Location: Bellingham, WA
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| Posted: Thu Jul 27, 2017 1:05 pm Post subject: Re: insulation |
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| Merian wrote: |
Reflectix will reduce coupled radiative transfer, and evaporative transfer - not convection or conduction
it is most useful AFTER an "insulation" is used to reduce convection |
Please explain, in your on words, how Reflectix reduces convection. |
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llilibel03
Samba Member
Joined: February 03, 2008
Posts: 767
Location: Redondo Beach California
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| Posted: Thu Jul 27, 2017 1:33 pm Post subject: Re: insulation |
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| PDXWesty wrote: |
As a mechanical engineer who does energy modeling and basically designs insulated boxes for a living, the construction of the van renders any amount of insulation that you can install in the wall cavities absolutely useless. It does nothing to keep the van warmer, colder or reduce the amount of heat transfer. The van body is full of "short circuits" of direct metal to metal pathways from interior to exterior that nullifies the insulation effectiveness. Also, the shear magnitude of single pane glass area with respect to solid wall panel area overcomes the insulation effectiveness. There is only about 10% of the van "envelope" that can actually be insulated anyway. I'm not even sure why VW would put it in to begin with.
If you want to understand this theory, Google the following terms:
-thermal break
-effective insulation value
If you were to do actual scientific testing on a van for heat transfer, my educated guess would be that adding insulation behind the cabinets would amount to less than a 1% difference in performance.
Now it may have other benefits for sound absorption, but to install anything for thermal improvement is not beneficial. Argue if you want, but scientific analysis would show no substantial benefit. I would not even replace it if it were my van. I think it causes more harm than good. |
I'd be interested to hear your take on Yeti vs Coleman Xtreme cost benefit analysis, as I'm about to pull the trigger on a cooler. My $20 Igloo is not cutting it anymore.
Anyways, my rust intervention is complete. I decided not to do the styrofoam because the pieces I bought would have meant piecing pieces together and Dave's query about the styrofoam squeaking freaked me out.
So I just put back the fiberglass as it did not create problems. I did cut it up about 4".
I also added some pieces of dynamat (I heard Fatmat was asphalt and could smell and my other half is super sensitive to smells).
In any case it couldn't hurt.
One good thing I discovered after putting all the cabinets back in- because of the opening for the green wire ground I can see the spot (or part of it) where my rust happened in the water tank cabinet so I can keep an eye out for moisture there.
Before-
After "Rust Fix" (turns the bare metal black)-
Dynamat (can't hurt)-
Fiberglass and finished intervention-
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scottz
Samba Member
Joined: April 13, 2008
Posts: 477
Location: Bellingham, WA
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| Posted: Thu Jul 27, 2017 1:55 pm Post subject: Re: insulation |
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| joetiger wrote: |
So which is better for sound absorption? Dynamat/Fatmat or 3M™ Thinsulate™ Acoustic Insulation SM600L?
I have Fatmat in my van in several spots (adhering to the 25% rule as opposed to full coverage) and after recently driving a Vanagon with zero sound insulation, I can attest to the fact that Fatmat makes a very noticeable difference. I'm intrigued by the 3M stuff, though. |
Dynamat and Fatmat are very similar and pretty much work the same way. I have both in my van and there are no smells coming from them. 25% coverage in the right places is probably just fine. I covered everything that I could because I had the material and the access.
I am not familiar with the 3M stuff. |
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Merian
Samba Member
Joined: January 04, 2014
Posts: 5212
Location: Orygun
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| Posted: Thu Jul 27, 2017 5:20 pm Post subject: Re: insulation |
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| scottz wrote: |
| Merian wrote: |
Reflectix will reduce coupled radiative transfer, and evaporative transfer - not convection or conduction
it is most useful AFTER an "insulation" is used to reduce convection |
Please explain, in your on words, how Reflectix reduces convection. |
please go back and re-read my post
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Merian
Samba Member
Joined: January 04, 2014
Posts: 5212
Location: Orygun
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| Posted: Thu Jul 27, 2017 5:26 pm Post subject: Re: insulation |
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| scottz wrote: |
| joetiger wrote: |
So which is better for sound absorption? Dynamat/Fatmat or 3M™ Thinsulate™ Acoustic Insulation SM600L?
I have Fatmat in my van in several spots (adhering to the 25% rule as opposed to full coverage) and after recently driving a Vanagon with zero sound insulation, I can attest to the fact that Fatmat makes a very noticeable difference. I'm intrigued by the 3M stuff, though. |
Dynamat and Fatmat are very similar and pretty much work the same way. I have both in my van and there are no smells coming from them. 25% coverage in the right places is probably just fine. I covered everything that I could because I had the material and the access.
I am not familiar with the 3M stuff. |
Dynamat is a dampening product, not a sound absorber - it sticks to the a metal panel (which resonates like a drum) and does 2 things: it reduces the amplitude of the sound and lowers the Q (see wiki for more)
AFAIK, the thinsulate IS a sound absorption material - you would have to find the engineering spec. for it, which IIRC is an STC number
But... just do this - put a dampener over at least 1/4 of the panel area
next, put a 'filler' layer there
3rd, you carefully put a layer of a "heavy mass loaded yada yada" on and it is floated by the filler so it does not touch the panel or dampener - the edges need to be carefully sealed
Lots of info on this in various threads (maybe too much...)
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scottz
Samba Member
Joined: April 13, 2008
Posts: 477
Location: Bellingham, WA
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| Posted: Thu Jul 27, 2017 5:29 pm Post subject: Re: insulation |
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| Merian wrote: |
| scottz wrote: |
| Merian wrote: |
Reflectix will reduce coupled radiative transfer, and evaporative transfer - not convection or conduction
it is most useful AFTER an "insulation" is used to reduce convection |
Please explain, in your on words, how Reflectix reduces convection. |
please go back and re-read my post |
My Bad!
The lack of capital letters and punctuation made your statement unclear. I understand what you're saying now. |
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erste
Samba Member
Joined: March 29, 2013
Posts: 1110
Location: San Francisco
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| Posted: Thu Jul 27, 2017 6:55 pm Post subject: Re: insulation |
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| Merian wrote: |
But... just do this - put a dampener over at least 1/4 of the panel area
next, put a 'filler' layer there
3rd, you carefully put a layer of a "heavy mass loaded yada yada" on and it is floated by the filler so it does not touch the panel or dampener - the edges need to be carefully sealed |
here's a pretty thorough link that breaks that process down:
https://www.sounddeadenershowdown.com/
OP - Great work! Looks really clean. |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9603
Location: Western WA
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| Posted: Thu Jul 27, 2017 8:49 pm Post subject: Re: insulation |
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| PDXWesty wrote: |
| If you were to do actual scientific testing on a van for heat transfer, my educated guess would be that adding insulation behind the cabinets would amount to less than a 1% difference in performance. |
I don't know about that..... 1% is pretty small. I think an insulated van will be noticeably warmer than one where the insulation has been removed.
Glass is about R-1, right? Thermopane is about R-2 maybe a little more. If your single pane glass is only half good, then again its only "half bad" right? Huge profit margins for window manufacturers and the resultant advertising programs (and not to mention building codes and convenient legislation mandating their purchase) has skewed a lot of folks' concept of heat transfer wrt glass.
If you look at a large body area where there's insulation between a cold exterior body panel, and the interior door panel, there will be less radiant heat loss with insulation. And there will be a temperature gradient from inside to van-body. Whereas with no insulation; the van body is in contact with full interior temp, temp differential is much higher therefore rate of heat loss will be much faster, perhaps magnitudes.
The fellas in this thread are big fans of insulation, they all swear it makes a difference. Pop top insulation. You can do it! The insulation they are using is a fraction of the thickness (10%?) of the fibreglas insulation.
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PDXWesty
Samba Member
Joined: April 11, 2006
Posts: 6243
Location: Portland OR
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| Posted: Fri Jul 28, 2017 7:34 am Post subject: Re: insulation |
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| Sodo wrote: |
I don't know about that..... 1% is pretty small. I think an insulated van will be noticeably warmer than one where the insulation has been removed.
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I was talking about if you only insulate the wall behind the cabinets. That has minimal affect when compared to the surface area of the van body. Most people don't strip the entire inside of their van and shove insulation into every crevice.
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Abscate
Samba Member
Joined: October 05, 2014
Posts: 22639
Location: NYC/Upstate/ROW
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| Posted: Fri Jul 28, 2017 7:57 am Post subject: Re: insulation |
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Doesnt dampening material create rust??
How can you tell a liquid water molecule from a gas water molecule ?
Sounds like a good pickup line for some of the places I frequent
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Merian
Samba Member
Joined: January 04, 2014
Posts: 5212
Location: Orygun
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| Posted: Fri Jul 28, 2017 12:02 pm Post subject: Re: insulation |
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| PDXWesty wrote: |
| Sodo wrote: |
I don't know about that..... 1% is pretty small. I think an insulated van will be noticeably warmer than one where the insulation has been removed.
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I was talking about if you only insulate the wall behind the cabinets. That has minimal affect when compared to the surface area of the van body. Most people don't strip the entire inside of their van and shove insulation into every crevice. |
I'd do the slider before the the wall behind the cabinets, as the cabinets provide some insulation
I now wonder how far upstate Abs is...
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MsTaboo
Samba Member
Joined: June 02, 2006
Posts: 4086
Location: East Kootenay, British Columbia
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| Posted: Fri Jul 28, 2017 12:50 pm Post subject: Re: insulation |
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| llilibel03 wrote: |
Fiberglass and finished intervention-
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Now just give that area under the insulation a spray of Fluid Film (after any new paint has had a chance to fully cure), and it will creep into any crevices and prevent rust from condensation.
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llilibel03
Samba Member
Joined: February 03, 2008
Posts: 767
Location: Redondo Beach California
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| Posted: Fri Jul 28, 2017 1:47 pm Post subject: Re: insulation |
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| MsTaboo wrote: |
| llilibel03 wrote: |
Fiberglass and finished intervention-
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Now just give that area under the insulation a spray of Fluid Film (after any new paint has had a chance to fully cure), and it will creep into any crevices and prevent rust from condensation. |
Darn. I wish you would have posted that earlier. I have all the cabinets back in.
Anyways, what I did might not be the very best but it is a whole lot better than nothing. |
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