Reefer Insulation and Thermal Bridging

[Stu Jackson]

a64, I agree, but still NOT an issue. The insulation is the stuff in between and the area of "touching" is minuscule and not germaine, he's only connecting the two NON insulating property covers.

PS - I wrote this earlier and just didn't hit send. Like sailorchic said.

Look, for the OP go to Kollmann's site and read what SHOULD be used and why:

http://www.kollmann-marine.com/answers.aspx

Why reinvent the wheel?

Good luck.

[NahanniV]

The blue(pink) board is easy to work with and practically impervious to water.
Edges cut cleanly and can be sanded and glued to make a perfect fit.

The Polyiso(?) I have seen is crumbly and needs to be sealed after cutting, hard to get good tight seams. And eventually bound to absorb moisture on a boat.

You say 9 cubic feet is big, so why not just add one extra inch of the blue board to equal the insulation value and avoid the possible problems. It would only bring your volume down by one cubic foot; Less volume = easier to cool as well, probably a bigger factor than the insulation.

Cheers,
JM.

[skipgundlach]

Iso, at least in my research into the issue when I totally started over (new ply walls, everything) on my box, is a crap shoot due to water intrusion.


Even with the blue/pink (Dow/the-other-folks) extruded board will eventually degas and lose insulation value.

We used it instead, and, belt-and-suspenders, painted each block with epoxy before insertion, to try to keep any possible water intrusion to a minimum.

I also used aluminum foil on the entire perimeter, then door-skin battens for an air barrier, before laddering (making the joints stairstep) all my corners to minimize any possible heat migration in the joints. Once the box was built, and before I installed the top portion, I fiberglassed the interior for strength and further air/water intrusion protection.

So, I had a radiant, conductive and thermal barrier to heat in my box. It seems to have worked well; when I decommission every time I have a shore excursion, leaving the boat on a ball, even with the doors open, it takes days for the interior temps to reach ambient. Of course, the downside to that is that recommissioning similarly takes a long time to get the foam fully cold (I keep my reefer at 32/34, and my freezer plate is set for 1.5/8 - which yields a 2° box hysteresis as well).

So, to your conundrum. Extruded poly, encased in epoxy as you lay it, with air and reflective barriers as you go to the perimeters, would be my recommendation.

FWIW, you may be aware that even vac panels will eventually lose their vac; I wish there was a way to easily replace my insulation, as I expect to own the boat long enough (it's already been over 10 years) for that to be an issue; I'll have to start over from scratch.

For any masochist who'd like to see that process, interspersed with the several other simultaneous projects, you can see it here:

Pictures: Flying Pig Early Refit + Projects/Early_Major_Alterations_Work

Start with the 12-04 and move onward...

L8R

Skip