Keep in mind that the GB tests are about 5 years old and the industry has
progressed considerably since them. Improvements in room temperature
getters has greatly reduced problems with gas infusion.
Two key points in using vacuum insulation. Keep the panels as large as
possible because the R value drops considerably close to the edges and
design the box so the panels can be replaced without the use of a jack
hammer the way your old box was. :-)
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at:
http://www.rutuonline.com
Shameless Commercial Division:
http://www.spade-anchor-us.com
"Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher
(net) - with apologies for the spamtrap wrote in message
...
I'm in the insulation phase of my icebox conversion to reefer and freezer.
Achieving a meaningful R value, while still retaining any interior space
(a
prior 19cf icebox is laid out to become a 6cf reefer and 2.6cf freezer by
adding 2" and 4" to the 2" of expanded polystyrene already there), is
proving more challenging than I thought.
Glacier bay has a derisive comparison of their panels against the other
VIP
available through resellers. While Glacier Bay has what seems to be a
clearly superior product, it also has a clearly superior price - one which
makes the reefer the single most expensive refit I'd consider at this time
(and there are many!), so unless I get radically more motivated, I'm
unlikely to do that.
It appears that the quality control is irregular on the other VIP, as the
R
values look to be all over the map from sample to sample. (That's from
looking at their published comparisons.)
Having despaired of finding a high R value cut-to-depth block foam, and
talking with Dow about their products, their change in blowing agents
about
a year ago makes it very unlikely I'd find any R8 (the prior Tuff-R
rating)
product available. The current R6.5 is certainly better than nothing, but
I'd still like better.
I believe I understand one of the challenges with VIP is future air
intrusion, sort of inevitable, if I understand the process correctly.
However, I think I understand that protecting that panel is also crucial.
Would you recommend a VIP sandwiched between some layers of foam, with
edge-protect foam around the perimeter of each (all encased in 6mil
plastic
and sealed, of course) as an effective means of radically increasing the R
on a 2 or 4 inch layer?
Or, given the apparent discrepancies in R from sample to sample, simply a
crap shoot?
Thanks.
L8R
Skip
--
Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2
"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain