Monthly Archives: July 2015

Sol Purpose

Fridge Rebuild

Let me preface this rebuild post with a statement that Nike never said… “just don’t do it!”

OK, now that that’s out of the way we can talk about the 7 month saga that was the refrigerator rebuild.  Just before Christmas last year (2014) the compressor packed in. It was a 12V Alder Barbor Super Cold unit which did not draw too much current (~5A when on).  It had been reliable enough for the four years I had had it, and I am not sure how long before I bought the boat it was installed.  When it died there were no winky blinky lights that were promised in the troubleshooting manual… it just curled up its toes and died.

I was pretty sure that the insulation surrounding the box was poor because…

  1. it was sprayed foam which is open cell
  2. the back of the seat cushion that rested against the bulkhead which the fridge backed up to was spotted with mildew
  3. the unit could not even keep frozen items hard.  Barely frozen was more the order of the day.

The original fridge was approximately 9.5CuFt which was all fridge with a small evaporator which was the freezer basket.  We liked the overall cubic footage as it allowed us plenty of space for food storage but we didn’t like the ratio of freezer to fridge.  Based on these facts we had 2 options…

  1. line the existing box with good insulation, replace the compressor/evaporator and fit a spillover wall to give us the desired ratio of fridge and freezer.
  2. tear out the old box and start from scratch.

Charlie, a friend of ours in the same marina, also with a Caliber 40, had just gone with option 1 as he didn’t want the work of a complete rebuild.  He had gone with a Frigoboat unit with keel cooler and smart speed controller.  The smart speed controller allowed the compressor to run at variable speeds based on the delta between desired temperature and actual temperature in the unit.  This means that the compressor would normally run at low speed but more often.  This is the most efficient way to run a compressor for longevity and power consumption.  Charlie was very happy with the results, both noise and power consumption.

I was just concerned that the existing insulation was breaking down or saturated and so I struggled with the decision of which way to go.  I let my Ridgid Jobmax make the decision for me by cutting through the wall of box and leaving myself with no option but to press on and rip out the old box.  The pictures below show the various stages of demo which ensued.

Like Charlie, I had also decided on the Frigoboat unit although I wanted to get the keel cooler with air cooled option as well so we could still run the fridge while the boat was on the hard as the keel cooler would be inoperative out of the water.

I ordered the following parts from Frigoboat based on our desired combination of 1/3 freezer and 2/3 fridge…

  • C50A                  Frigoboat Air Cooled compressor Unit; Capri 50; Danfoss BD50 Compressor
  • F-E50361Z         Keel Cooler
  • V200F                Very Large Flat Evaporator. 40.25″ x 10.5″  (capacity: 10-18cuft fridge or 5-8cuft freezer)
  • T-Guardian         Digital thermostat
  • T-Merlin              Smart Speed Controller
  • T-C3030-12         Spillover fan/thermostat kit, digital

I thought that once finished I would end up with a slightly smaller box and the calculation for evaporator size is to divide the capacity of the fridge by two, add it to the capacity of the freezer and select the next bigger evaporator.  I thought that the V200F would therefore suffice.

Once the tear out was complete the design could start.  I did not want to lift off the countertop as it would also involve removing the cupboards and would render the galley inoperable for the length of the project. As we are liveaboards I didn’t think this was an option.  Debbie reinforced this notion vehemently 🙂

This meant that I had to build the whole box through the hole that the lids fitted into which is smaller than the dimensions of the box itself (see the first picture of the set above)… fun times!

I had been reading up on other rebuild projects and took notes from the following two especially…

Jason and Christy’s page ( was useful as they were rebuilding a Caliber 40 fridge so I could see what I was getting into.  Wally Bryant’s page was useful as he employed many techniques that I could see as useful. He also introduced me to materials I did not know you could get.

I had several requirements for my design which were…

  1. air gap between the hull and insulation to act as a thermal barrier and allow the hull to “sweat” into the bilge without getting the insulation wet.
  2. radiant moisture barrier on the outside of the insulation and the inside.  This would also protect it from moisture and reflect heat.
  3. air gap between the forward wall of the box and the bulkhead that the salon cushions were mounted on.  This would stop mildew, caused by moisture forming on the bulkhead.
  4. freezer at the forward end of the box as it would be less frequently accessed and that end of the box was harder to reach into.
  5. very high R value insulation to reduce the required thickness of the insulation and thereby keep the capacity of the box at a maximum.
  6. replace the lid springs used to hold the lid open with something that would prevent them from slamming shut on body parts if knocked (the lids weigh about 15 pounds each)
  7. construction of the box should require the least fiberglass construction skills as I was a relative novice in this arena.
  8. improve the insulation in the fridge roof, as the old one was only an inch thick and was made up of sheets of plywood on the underside of the countertop.

Off to the drawing board I went to overcome all these obstacles.  Eventually I solved each as follows…

  1. create a framework of Structural Fiberglass (FRP) angles and channels affixed to the hull as well as the fore and aft ends of the box to keep the insulation off the hull
  2. use heavy duty 2mil Mylar against the framework and on the inside layer of insulation against the inner box
  3. attach FRP channels to the forward bulkhead to create an air gap to mount the insulation on
  4. this was not just as simple as making a decision, as it meant that the tubing from the evaporator to the keel cooler and compressor and back had to end up at the forward end of the box.  The tubing that came with the evaporator was 9ft and the tubing that came with the keel cooler was 5ft and could not be extended.  I therefore decided to mount the compressor under the sink (next to the fridge), the keel cooler thru hull would be under the port settee just in front of the bulkhead and the tubing for the evaporator would enter the box from the forward end (to familiarize yourself with the cabin layout please see this link)
  5. After much research I went with Aerogel Spaceloft insulation. It has an R value of 10/inch which beats any foam board and is hydrophobic and so should resist waterlogging better than most materials.  That does come at a price though.  It came on a 57″ wide roll at $20 per linear foot.  My estimations were that I would need around 83ft of the material and with shipping that came to $1,885.63 for insulation alone 😦
  6. I read a blog on another Caliber where they replaced the springs with hydraulic struts which appealed to me.  The lids would be held open and could therefore never fall on the fridge rummager
  7. Decided to go with prefabricated FRP sheets which I would cut to shape and epoxy together for the box walls which meant that the box could not follow the gentle curves of the hull but had to be more angular.  This affected the frame build, which was the solution to requirement one, as the layers of insulation would sit on the framework and also against the inner box.  The framework therefore also had to follow the lines of the inner box as the insulation was basically uncompressible.  I chose the 24″ x 36″ x 1/4″ chemically resistant sheets as they were an off-white
  8. Increased the thickness of the lids by an 1.25″ to accommodate more insulation.  Also insulate the rest of the roof properly and have an RFP inside roof like the walls and floor of the box

With these decisions made, it was time to take numerous measurements and sketch out some plans.  Many sheets of graph paper later I had the skeleton of the design complete and started ordering the materials.  Two of the sketches that I made, which I photographed before throwing out, are shown below.

Before any construction could begin, I got the cavity that the fridge would be build in cleaned out of all debris, lightly sanded, washed and wiped down with MEK.

Having the freezer at the forward end of the space worked well as the curve of the hull made the aft end of the cavity narrower than the forward end.  This would allow more layers of insulation at the forward end to insulate the freezer section and still be able to maintain parallel walls fore and aft.  There was also a 1″ step out at the forward end of the inner wall which would do the same thing, a stroke of luck.  If this is not clear then the picture gallery below should make it easier to understand.

The stages of the build can be broken down as follows…

      1. drilled holes in the bottom of the space to allow any moisture that dripped down the inside of the hull to make it into the bilge
      2. screwed angles to the fore and aft ends of the space, to attach U channels to, for supporting the moisture barrier and insulation.  The upper set of angles is vertical to make the last part of the outside wall right angles to the roof for easier construction.  This meant there was space behind the upper angles (see the last picture in the gallery below) to run a pipe.  More on that later.
      3. epoxied angle mounts to the hull itself, midway between the forward and aft end of the space, to attach the staggered U channels
      4. attached offset wooden supports on the midpoint angles to account for the curvature of the hull and allow the U channels to run parallel to the inside wall.
      5. attached angle supports under the roof of the fridge.   The lone angle hanging down from the ceiling (last picture in gallery) will support the angle which will make up the corner of the wall and roof once the insulation is installed.  The wooden block on the far wall in the picture will support the end of the angle along with a matching block on the aft wall.
    1. painted the space with bilge coat to protect the existing walls and floor from moisture
    2. heated and shaped schedule 40 pipe.  This run will go from the bottom of the forward end of the space behind the navigation panel to the cupboard behind the port settee back and will carry most of wiring that currently goes through the cupboards above the galley counter.  Joined the sections together behind the upper set of angles
    3. attached U channels to angles to create framework to attach reflective vapor barrier and subsequent insulation

As I had never worked with the Spaceloft insulation before, I decided to reinsulate the lids first as I could do that more easily outside the fridge.  I removed the bottoms of the lids and took out the old sprayed insulation.  I noticed that the holes routed out for the lid latches actually penetrated through to the insulation and had caused water ingress.  I added a marine plywood “patch” to cover this hole and keep water out.  I added 1.25″ of teak to the frame of the lids to make them deeper and able to accommodate 7 layers of Spaceloft.  The Spaceloft was 10mm thick and so 7 layers would give me 70mm or 2.75″ and therefore an R value of 28.

I sprayed the inside lid surfaces with 3M Super 77 adhesive and lined the lid with the Mylar and sealed any open edges with HVAC foil tape.  You could equate it to lining a baking dish and having enough pastry to cover the pie once filled as well.  I then cut and layered Spaceloft until I had reached the desired thickness.

A word of caution when dealing with Spaceloft; the material is incredibly dusty due to its structure.  It is a must to wear a respirator and I don’t mean a dusk mask.  You should also wear eye protection to keep the dust out.  Gloves are another good idea as it will dry out your skin something terrible.  It is pliable as it comes on a roll and can be cut with most good quality tin snips which is what I used for the whole project.

Once I had layered the insulation I put the lid on the pie and sealed it with the foil tape.  I then replaced the base of the lid and reattached the Formica.

With the lids done I felt better about the whole process an so it was time to attack the fridge itself.  This was done in the following order…

  1. removed the lower U channels to allow me to get inside the fridge for the first half of the work
  2. climbed in and started lining the U channels with Mylar.  Once I had applied that around the upper half of the space I stopped.  I would apply the remaining Mylar from outside the fridge once the upper insulation was installed
  3. applied insulation to the outside freezer end of the space until it came up to the level of the U channels in the aft section of the space.  I staggered the layers so that there was overlap between each layer, reducing the chance of a straight path for cold air to escape.  Used 3M Super 77 to attach insulation to the Mylar and subsequent insulation layers.  Then applied layers of insulation the whole length of the fridge until I had it to the correct thickness.  In the gallery below, you can count 5 layers before the insulation comes up to the level of the aft section of channels.  Another 7 layers across the whole length of the fridge.  This meant that the freezer had 120mm or 4.75″ with an R value of 48 and the fridge had 7 layers for an R value of 28.  Should be good enough 😉
  4. Applied insulation to the underside of the roof until it reached the same thickness as the lids.
  5. Attached the angle that would support the join between the roof and upper piece of the outside wall.  Like the angles that were to support the floor, this had to be installed before the fore and aft insulation, as it was attached to the fore and aft walls
  6. applied insulation to the inside wall of the space to bring it up to the same thickness as the outside.
  7. applied insulation to the top half of the forward end of the space
  8. applied insulation to the top half of the aft end of the space
  9. climbed out and reattached the U channels before applying the remaining Mylar
  10. carried on applying layers of insulation until floor, inside and outside walls were done
  11. Attached the 2 angles that would support the floor to the fore and aft walls.  This had to be done before attaching the insulation to the lower half of the fore and aft walls as these angles were glassed in place for strength.  The mount points can be seen in the last picture of the gallery below
  12. applied the insulation to the required thickness to the remainder of the fore and aft walls

See the gallery below for various stages of this process

As you can see from the last picture, there were several angle steps from the floor of the fridge to the roof on the outside.  I intended to use more angle to join corner sections where possible.  However the angles up the outside edge were not so regular.  I took the angle and partially cut through the wall at the corner to weaken it, then used screws and wooden blocks to create the desired angle and glassed it in place.  This can be seen below.  This was the angle used to join the floor to the first section of outside wall.

With everything prepared it was time to work on the walls.  As stated earlier, the FRP sheets were an off-white and the surface relatively smooth.  As I wanted a finish as white and smooth as possible, for cleaning and food protection, I decided to mix West Systems epoxy with a white pigment and pour it on one side of the FRP sheet.  To remove as many bubbles as possible I tried 2 methods.  First I tried to use a blow torch and move it briskly over the freshly poured epoxy.  This worked but it was hard to stop getting a little discoloration of the surface. I then tried lacquer thinner in a spray bottle.  The thinner broke the surface tension on the bubbles and left no discoloration at all.  I prepped all 9 sheets this way.  Thanks to my friend Al Goethe who was kind enough to let me use his garage for this part of the project.  Please see below for the steps followed.

9 sheets of 24″ x 36″ may seem like a little overkill for the walls of the fridge but this included the spillover wall as well which would be insulated with three layers of Spaceloft and would therefore have to be covered on both surfaces.  There was also the problem that the inside wall was bigger than 24″ x 36″ and so would require 2 sheets.  To hide the seam between the pieces I decided to place it  behind the edge of the spillover wall.

The fabrication of the walls was carried out as follows…

  1. applied Mylar to the insulation where the floor would be affixed
  2. epoxied angles to the ends of the floor section for future attachment to the end walls
  3. epoxied the floor piece to the angles running fore and aft
  4. cut a piece of angle down its length to create a straight edge and epoxied it to the back of the join of the two pieces that would make up the inside wall
  5. epoxied angles to the fore and aft ends of the inside wall for future attachment to the end walls
  6. applied Mylar to the inside wall insulation and installed the inside wall.  This wall was through bolted to the 1.25″ lip that was added to the lid opening.  This provided all the strength needed to hang the box from and was carried out for all 4 walls.  The angles supporting the floor were a belt and braces attempt to make sure everything was strong enough.  The fit was so tight I had to use a carjack to hold it in place till I could get the clamps attached and let the epoxy set
  7. measured and created a template for the aft end wall (didn’t want to waste an FRP sheet if I made a mistake).  Attached angles along the outboard edge of the piece and tried to slide it in place.  As I wanted no air gap between the walls and the insulation I made the fit very tight on purpose.  I found that the angles bunched up the insulation when dragged across it.  To stop this I bought some thin galvanized steel flashing and taped it to the insulation where it was rubbing.  The idea was that once the end wall was situated I could pull out the flashing.  This worked as I had hoped it would and can be seen in the gallery below
  8. I then used the template to cut the FRP sheet and epoxied the angles used earlier on the template to its outside edges
  9. applied Mylar to the insulation where the aft wall would be affixed
  10. installed the aft wall, hanging it from the added lid lip
  11. used the same template to cut the forward wall and repeated steps 9 and 10 for that wall as well.
  12. cut the three sections that would make up the stepped outside wall of the fridge
  13. to join the sections and add strength I had to fabricate fiberglass strips with the correct angle to bridge the sections.  I cut out lengths of wax paper and  loaded them with epoxy.  I then layered chopped strand mat, epoxy, woven mat, more epoxy and another chopped strand mat.  I laid the wax paper on cardboard sheets which I could angle and  support from behind to give the desired angle and let it set.  Once cured I pulled off the wax paper, cleaned up the edges and epoxied them to one of the edges running fore and aft on the wall sections.  You can just see one of these fabricated pieces poking out the top of the section being fixed in place in the last picture of the gallery below
  14. The last section of the outside wall was attached and then the pieces of roof that would also act as the lip to support the lids were epoxied in.  One piece was omitted as I had to leave room to install the spillover wall once built.

The next part of the project was the fabrication of the spillover wall.  I wanted to make sure that the spillover wall felt like an integral part of the fridge so I decided to hide all the cabling and fan inside the wall itself.   I wanted to have three layers of insulation between the FRP sheets that made up the wall to give me an R value of 12 between the fridge and the freezer.  I had already worked out that I was going to add tabs to the fridge walls which I would use to hold the spillover wall in place.  This would allow me to use regular caulk to seal the edges of the spillover wall to the walls of the fridge and still have the structural strength to support the wall.  As the evaporator would not be able to be removed if the spillover wall was epoxied in place I wanted to be able to remove the wall should I need to work on any part of the unit.

To ensure that the tabs would not be visible I inset the walls that join the 2 faces of the wall.  I left a small gap at the upper outboard corner to run the cable that supplied the spillover fan.  I then installed one layer of insulation, ran the cable, installed 2 more layers of insulation and epoxied it all together.  I left about 12 inches of the stripped cable in a small cavity next to the fan so that it could be removed and easily replaced if required.

With the spillover wall built it was time to finish the inside of the fridge.  The finish on the walls was not what I had hoped as the poured epoxy still left very small “pores” which made the surface mark up easily.  I thought that if it visibly marked up easily then it would also hold bacteria etc .  I therefore decided to get all the walls gelcoated to make it a a much smoother finish.  With that decision made it was easier to move forward with cleaning up the inside edges.  I filleted all right angle edges and used 3M premium filler to round off the wider angled edges.  I then had a local shop spray 5 coats of gelcoat on the fridge walls and spillover wall

Before I could install the spillover wall I had to shape and fit the evaporator so that once the wall was in place I could affix the evaporator.  I had already calculated the size of all three edges of the evaporator.  The Frigoboat instructions state that you should heat up the section of evaporator to 220˚F before attempting to bend it.  This would reduce the chance of the paint cracking.  I took some 2″ PVC pipe and wrapped it in a layer of the insulation to stop the pipe deforming.  I then clamped that to a workbench to hold the evaporator in place prior to bending.  I used a heat gun to bring the metal up to temperature and then made the bends quickly.

This might have been one of the easier steps of the whole build, thankfully!

Next I unrolled the 9′ of copper tubing attached to the evaporator, ran it through the wall of the freezer, placed the evaporator in the freezer section, installed the spillover wall and caulked it in place on both sides.  Once the caulk had set I attached the evaporator to all the mount points.

Now for the shelving.  I took a piece of hardboard and made up some mock-up shelves so that I would not waste much money if I made a few mistakes.  I then used sheets of 1/8″ acrylic and made three shelves for the fridge and used teak 1/4 round strips for the open edges to create a small lip.  I used the shelf from the old fridge to make the shelf for the freezer, sort of a something old, something new type thing.  Acrylic is very hard to work with and required the use of a router which was all new to me.  I used a Ridgid laminate router which worked perfectly once I learned how to use it 🙂  The shots below show the mock-up shelves and the cut acrylic ones in place.

Next task was the keel cooler.  As mentioned earlier, I had decided to place it under the port side settee.  I wanted to install it as low as possible to reduce the chance of it ever coming out of the water on a port tack. The only place was next the the existing thru hull for the galley sink.  I removed all bilge paint from the section of hull, cut out a piece of G10 and epoxied it in place.  We then had the boat quick hauled and installed the keel cooler.  Once installed I built a wall to protect the keel cooler from sliding objects under the settee.

The bundle of wires/pipes in the last picture above shows three refrigerant tubes, 2 from the keel cooler and one from the evaporator.  The other wires are the power supply from the DC panel and the power supply to the fridge and freezer control panels.

I build a housing on the shelf behind the port settee to mount the panels.  I used marine ply with a teak quarter turn for the corner.  Assembly is shown below

I installed the freezer panel on the bottom and piggie backed the fridge panel off the power supply to the freezer panel.  I then fed both thermostats through the same hole that the evaporator tubing exited the freezer.  I attached them to the fridge wall as shown in the shelving section above.  The power supply to the spillover wall fan was also fed through the same hole and attached the the fridge panel as described in the fridge panel hyperlink above.  The hole was then filled with an insulating foam sealant and that was covered on the inside with plumbers putty to keep moisture out of the foam.

With the panels installed it was time to install the compressor in the cupboard under the sink.  I had already drilled the 2 holes necessary for the wiring/tubing runs to the space.  One was just above the floor under the settee in front of the galley (can be seen in the keel cooler pictures above).  The other was just under the shelf under the sink.  This gave about 12 inches of rise from one hole to the other which allowed me to not exceed the bend radius of the tubing while feeding it in.  There is about 3 inches of space behind the drawers that allowed for easy routing.  Next I removed the tiles that cover the floor of the cupboard and placed the compressor on the floor.  I left about 5 inches space to run the tubing and cables between the compressor and the side wall.  I wanted the compressor to be orientated so that I could access the controller wiring, quick connects for the tubing  and also the caps for topping up refrigerant levels.  Unfortunately this meant that the fan would face the front wall of the cupboard.  I decided to take advantage of this and marked and cut a hole in the front wall that led under the settee in front of the galley.  I then fitted a 120mm computer fan grill to the outside of the hole to protect the fan blades from anything shifting about under the settee.  This now meant that if the boat was hauled and we wanted to use the air cooler then we would be drawing air from a different space than where the compressor was situated and this would stop the build up of heat.

The compressor was then attached to the floor with the fan housing up against the hole.  To protect the compressor and tubing from items in the cupboard, I fabricated a wall from perforated aluminum sheet.  To this I attached a switch to allow me to turn on or off the fan when the boat was hauled.   I then cut the tiles to fit around the wall.  Pictures of this installation can be seen below.

The last piece of the puzzle was the installation of the lids.  I painted the sides of the lids and the sides of the holes they fitted into with several coats of White Easy Epoxy from Petit.  As I mentioned earlier, I had decided to go with hydraulic struts to open and support the lids.   Once I had installed the mounts under the fridge lid support lips and on the underside of the lids, I was able to attach the struts. As the lids would open themselves I also had to attach latches on the lids to hold them closed.  The old lids used gravity to stay shut so they had none installed.  The problem was that due to the thickness of the plywood that made up the top of the lids, I could not route out the holes to recess the latches into the lids without cutting into the insulation.  I therefore had to recess the latches into the adjoining countertop and put the strike plate on the lid itself.  This added another layer of complexity as the chamfered edge of the latch bolt is designed to be in the latch attached to the lid and not the countertop.  I therefore had to disassemble the latch and file the slot for the latch bolt to allow me to turn the latch bolt through 180°.  Once reassembled I was able to route out the shapes and recess the latch and strike plates. I added an aluminum strip to the face of the lid so that the latch bolt would not gouge the paint.  It worked well until I turned the fridge on.  After the fridge and freezer got down to operating temperatures, the oil in the struts became viscous enough that it took about 20 seconds for them to open the lids. This was no use so I had to go back to the drawing board.  I decided to remove the struts and go with elbow catches mounted on the galley cupboard faces which would hold the lids open.  The gallery below shows some shots of this.

There is still some work to be done.  I am not happy with the lid seals.  I bought the thinnest EPDM weather stripping to seal the lids but it was too hard to close the lids with it installed even though I bought the 1/4″ thickness.  I ended up going with a thinner non-EPDM foam tape but that does not seal as well and seems to be breaking down in the colder temperatures.

There is also the issue that the fridge never turns on unless we put produce in that is not cold.  The combination of good insulation and the spillover fan hole being big enough to transfer cold air from the freezer without the fan running means that the fridge is constantly below its desired operating temperature.  The lower half of the fridge, where the thermostat is, sits between 26F and 29F all day and so some of the stuff in there is colder than desired.  I will fabricate a sliding door that I can partially close to reduce the cold air that passes through from the freezer.

The next time we defrost the fridge/freezer I will take care of both tasks but for now we simply enjoy ice cream that’s not mush and a freezer capacity that is actually of some use.  All I can say is thank god its almost over.

For those who are interested I always keep a very accurate account of costs, down to the last screw, and the total cost of this project was $6337.54.  This is obviously a vary large sum of money and would have bought us a nice sub zero in a normal house… but boats are not normal houses!  Would I have paid that much at the outset if I had known ahead of time?  Was not in our budget, so no.  However once you commit its not really an option to stop and we did all the work ourselves, bar the gelcoat, so I am not sure how it could have been done much cheaper with the quality components used.  Hopefully it will pay us back in convenience, energy savings and peace of mind that we know what we have and how its put together.  I also hope that we will not have to do anything to the unit till we pass the boat onto someone else about a decade down the line 😛