Re-insulating The Ice Box/Refrigerator
(July 2008)  


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This summer (July 2008) we (Tom and Kaye Assenmacher) have undertaken several 'projects' on our 1975 MK-II Yawl SHEARWATER.  One of these projects was to re-insulate the refrigerator (ice box).  The original box, as all MK-II owners know, is at best only fairly well insulated.  Several years ago, while doing general refurbishing of the boat's interior, we injected several cans of 'builder's' foam insulation into the voids between the icebox liner and the hull, bottom and sides with only limited success.  Our box still has the original owner-installed air cooled Adler-Barbour Cold Machine which was installed probably in the 1976-1980 time frame (we've owned the boat since 1982), and believe it or not, still works great (we had it recharged years ago, had to replace the electronic control unit also years ago, and have had to replace the cooling fan several times over the years)!  The unit draws about 5.5 amperes when it's running, and before re-insulating, ran about 50% of the time.

We had read several articles about re-insulating the box, some of which required removal of the box's interior - we didn't want to do that!  Another article we read suggested applying a foam/fiberglass liner to the interior, so, we elected to re-insulate in this manner.

We had also heard of a commercial fiberglass panel material, called Sequentia Fiberglass Reinforced Wall Panel, available from building supply stores such as Lowes.  This material is a fiberglass laminate, about 1/16th (actually 0.072") inch thick, and comes in various colors and textures (we chose white with a slight 'pebble' texture), and comes in a 4' x 8' panel and costs about $30 per sheet. We decided to 'glue' the insulation material to the Sequentia panel material, which would make a rigid foam/fiberglas panel which would be easy to clean, and relatively easy to install.

As the insulating material, we chose 1" blue extruded polystyrene (also known as 'blue board') rigid foam insulation (also available at Lowes or any building supply house), which is light, doesn't absorb moisture, has an a relatively high "R" value of 5.  We figured adding this insulation to the existing insulation would provide adequate insulation with minimal effort.

We started the project by making some rough paper patterns of the ice box interior, as it was impossible to install large sections of the foam/fiberglass panel material. 


Paper Pattern of Segment


We then 'glued' the blue foam insulation board to the rear side of the Sequential glass panel material using thickened epoxy (West Epoxy thickened with #404 structural adhesive powder).  The blue foam board is NOT dissolved by the epoxy, and makes for a very strong panel.


Epoxy 'Glue'



Gluing Foam to Sequentia Fiberglass Panel Material
(Panel Material be trimmed with Tin Snips)


We then began the cutting and fitting of the panels, which was quite a time consuming task.  We ended up with approximately 15 panel segments which covered the entire box interior, i.e., bottom, sides and top (we left the refrigerator freezer evaporator box in the icebox during this process). 


Laying Out Insulating Panels Prior To Cutting Sequentia



Some Of The 'Laminated' Panels Prior To Trial Fitting


We then 'glued' the fitted segments into the box using 3M 5200 adhesive, leaving approximately 3/16" between segments to allow for injection of 5200, forming waterproof  and bonded seams (these seams were masked with tape to keep the installation neat and tidy). 


Segments Were Masked Prior To Installation



Spacers Were Inserted Between Panels To Provide Clearance For 3M 5200 Adhesive



You will note that the bottom of the Ice Box, being curved, and the foam laminate being quite rigid, required several segments to conform to the curvature.


Bottom Segments 'Glued' In Place With 3M 5200
(Note - Some Panels Temporarily Held In Place With SS Screws)



The Box Nearing Completion



The Completed Box
(Note Small Computer 'Muffin' Fan To Aid Air Circulation In The Box)



We also replaced the old styrofoam insulation in the icebox lids with "blue board".  The entire project took approximately 40 hours (could probably do it in less time now that the 'learning'  curve has been established.  We have begun taking data to determine the effectiveness of the added insulation - preliminary results show a marked improvement of box temperature, decreased refrigerator running time, with commensurate energy savings (our  two 85Watt solar panels can now keep up with the refrigerator electrical consumption).

(Ed. Note:  In April 2013, we completed our 4th Bahamian Cruise (to the Abacos), and the original Adler-Barbour Cold Machine is still working as advertised.  We now have 3 solar panels installed (2-85 Watt panels on the dodger, and 1-130 Watt panel over the Bimini) which satisfies all the 12V DC requirements aboard SHEARWATER.  Of course, after 2 days of no sunlight on cloudy days, we may need to run the engine for an hour or so to recharge the batteries.  The Sequentia panels are still in place, and working great to keep the interior clean.)