Just as a data point, I measured in the 160s F for the exterior of my blue-black van:I plan to adhere the thinsulate to the metal wall with squares of 3M Fastener TB3571/TB3572 Hook/Loop (ie velcro). The glue of the velcro is more important than the velcro itself, and 3M's selector guide indicates this part will hold up to 200 degrees F, which is pretty good (I have white paint by the way)
I plan to adhere the thinsulate layers (as applicable depending on void depth) to each other using 3M 76 Hi-Tack Spray Adhesive. I selected this spray adhesive because its datasheet says it is "an excellent choice for fabric headliners" and is good for 230 degrees F; specifically marketed for "fabric in van conversions" and to "bond insulation in aircraft interiors" here.
I received my 3M MA6720 Thinsulate. Here is my plan for install. Comments welcome (except for recommending use of spray foam.. hah hah).
(steel vehicle skin)
-- THINSULATE 2"--
-- THINSTLATE (additional 2") --
-- REFLECTIX --
Check eBay, it's there!Where did you buy the MA6720 from?
Thanks. This validates my concern of using high-temp adhesives in this case.Just as a data point, I measured in the 160s F for the exterior of my blue-black van:
I don't think you are off, there may be some who disagree with me, but I dont agree with people putting true vapour barriers on the inside of their vans.Hmm.. the more I think about this the less I like the idea of a VAPOR barrier at all. Read this. Maybe what we need is a vapor-breathable AIR-barrier! That is, we don't want drafts and air currents that carry our moist air out of the van to touch the cold metal skin as it passes by. We DO want moisture against this skin to evaporate and diffuse as necessary without being trapped. Even with reflectix against the metal skin directly you run the risk of air pockets and tape failures (I wonder how well the adhesive of reflectix tape holds up under temp!) where moisture can collect.
Tyvec house wrap has HIGH vapor permeability, ASTM E96 of 400 g/m^2 in 24hrs. Reflectix is LOW .02 perms = .013 g/m^2 in 24hrs.
This is a big difference. Have we been thinking the need for a vapor barrier incorrectly or am I off here?
...describe/explain a reason or scenario where you would need to undo a sprayfoam application...I think your idea of a hybrid solution is a good one, and I agree with others that the spray foam solves the issues of any possible air gap where condensation can form. That said, I don't like the lack of reversibility of that installation. I like to be able to easily undo what I do to the van, when reasonable.
It would be nice to see some pictures. Do you have a passenger van?Started the insulation effort. I'm about 2/3 done with the project and I have used 125 sq ft. Roof and everything above the windows is done. So far the van seems noticeably quieter. Can't hear the rain drops on the sheet metal nearly as well and my test drive yields good subjective results. Headliners still out so it should only get better.
The Thinsulate is very easy to work with. The MSDS indicates no health hazards, and there is no itch and just a little bit of white dust after cutting. Can cut with scissors, but also used a a rotary quilting cutter to get cleaner cuts. It will tear if you are too rough with it. One side scrim is a lot more fragile, the other side is a bit thicker scrim. The 3M velcro only adheres well to the thicker scrim, it just pulls off too easily if stuck to the thiner side. You do have to be a bit gentle with it if you use velcro since the Thinsulate will tear before the the velcro will release unless you hold hold the scrim as you pull. I used small squares of velcro for the ceiling panels. The material lofts quite a bit after you start working with it, about 2". I am finding that in the upper bays and ceiling only need one layer of the stuff. Below the windows it can support double layers.
I think the Thinsulate is a bit too fragile to be handled frequently. I do plan cut window shades for all the windows using reflectix, and mount them with 3M dual-lock.If that is a window van that you have you could consider making some window inserts out of any leftover Thinsulate. Pretty ideal material for something easy to store when not needed. Figure you'd use them on the coldest nights/hottest days when visibility was not an issue.
I had in mind that you'd sandwich the Thinsulate between some mylar and curtain fabric.I think the Thinsulate is a bit too fragile to be handled frequently. I do plan cut window shades for all the windows using reflectix, and mount them with 3M dual-lock.