Built-in Freezer - Liner Material?

[jdecris]

I have a ‘91 Grand Banks Classic with the Galley down layout. Upper and lower front opening built-in refrigerators, and countertop top opening built-in freezer.

I removed the original Grunert system in 2018 after I bought the boat and installed two Seafrost BDXP 12v compressor systems, one for each refrigerator. I did not change the existing insulation and stainless steel interior liners - just installed new plates, etc. - and both refrigerators work fine.

I now want to have a working freezer on board. The existing top loading freezer box, also lined with stainless steel sheet, is too large for both my needs and for the amount of 12v electricity it would consume.

So I want to make the box smaller by fitting rigid foam insulation inside the existing box and then installing a new liner over the newly installed foam. And then installing the appropriately sized Seafrost plates. The box shape right now is a flat bottom and three plumb vertical sides, with the fourth outboard side matching the slope of the hull. I’ll probably make that sloped side plumb vertical when I rebuild the interior.

My question is - what material to use as a liner over the foam?

Ideally it would be “food safe” and produce no moisture/condensation. And obviously not absorb moisture, not be susceptible to rot or decay, and be able to be formed into a watertight box.

Stainless would (might?) have the tendency to sweat, and not so easy to seal the inside corners. And most plastic-type sheet materials are not food safe or do not glue well.

Laying fiberglass cloth and epoxy over the foam would be a tough and messy job.

King Starboard is food safe - but as I understand it - cannot be glued - and has to be either mechanically fastened or heat tip welded - both not so reasonable for a box built inside an existing box. The only way around sealing the inside corners of King Starboard - or other not glue-able sheet plastics - that I’ve come up with is making fasten-able shaped inside corner strips and fastening and caulking them over the plastic sheet to seal the box corners.

Gluing plastic sheet goods with solvent type glues on the workbench is one thing - gluing sheets while reaching down into a top opening existing box with a smaller hatch access - is another story.

So… I’d appreciate hearing from anyone who’s successfully re-insulated and re-lined an onboard freezer box. Or has had success connecting food safe sheet plastic inside corners with a glue/sealant that will hold and stay watertight.

Thanks.

 

[Bmarler]

I have a ‘91 Grand Banks Classic with the Galley down layout. Upper and lower front opening built-in refrigerators, and countertop top opening built-in freezer.

I removed the original Grunert system in 2018 after I bought the boat and installed two Seafrost BDXP 12v compressor systems, one for each refrigerator. I did not change the existing insulation and stainless steel interior liners - just installed new plates, etc. - and both refrigerators work fine.

I now want to have a working freezer on board. The existing top loading freezer box, also lined with stainless steel sheet, is too large for both my needs and for the amount of 12v electricity it would consume.

So I want to make the box smaller by fitting rigid foam insulation inside the existing box and then installing a new liner over the newly installed foam. And then installing the appropriately sized Seafrost plates. The box shape right now is a flat bottom and three plumb vertical sides, with the fourth outboard side matching the slope of the hull. I’ll probably make that sloped side plumb vertical when I rebuild the interior.

My question is - what material to use as a liner over the foam?

Ideally it would be “food safe” and produce no moisture/condensation. And obviously not absorb moisture, not be susceptible to rot or decay, and be able to be formed into a watertight box.

Stainless would (might?) have the tendency to sweat, and not so easy to seal the inside corners. And most plastic-type sheet materials are not food safe or do not glue well.

Laying fiberglass cloth and epoxy over the foam would be a tough and messy job.

King Starboard is food safe - but as I understand it - cannot be glued - and has to be either mechanically fastened or heat tip welded - both not so reasonable for a box built inside an existing box. The only way around sealing the inside corners of King Starboard - or other not glue-able sheet plastics - that I’ve come up with is making fasten-able shaped inside corner strips and fastening and caulking them over the plastic sheet to seal the box corners.

Gluing plastic sheet goods with solvent type glues on the workbench is one thing - gluing sheets while reaching down into a top opening existing box with a smaller hatch access - is another story.

So… I’d appreciate hearing from anyone who’s successfully re-insulated and re-lined an onboard freezer box. Or has had success connecting food safe sheet plastic inside corners with a glue/sealant that will hold and stay watertight.

Thanks.

Have you thought about having a sheet metal fabricator making up a drop in tub? Essentially an open top box made of stainless that fits through the existing lid. Maybe use pourable foam to insulate and lock in place, trim the top with more formed stainless sheet stock.

 

[mvweebles]

For liner, GPO3 sheets. McMaster has them in a variety of sizes and thicknesses. Paint to suit. Not sure how food-grade it is though (nor the paint). But definitely impervious to moisture.

https://www.mcmaster.com/sheets/grade~gpo3/

Peter

 

[jdecris]

I can't do a drop in tub as the existing top loading hatch is smaller than the box below.

 

[cafesport]

Sounds like you need to adopt the building a ship inside a bottle approach. Build a form on the bench then layup your gelcoat mat and glass on the plug. Cut the box into keyed pieces that will fit into the space. Foam the pieces of the box in place. Refinish the inside seams in situ with a layer of mat and putty. Finish with gelcoat.

 

[Itwasntme]

Last one I made, I used aerogel for the insulation. Expensive but much higher R value and does not absorb water.
I used sheet fiberglass from the local hardware store (Shell Lumber in Miami) to make the box. eplastics.com has them also.
or, if you want to save money, buy a big sheet of window glass, lay it on a sturdy table or a 4x8 sheet of plywood on two sawhorses, and layup the fiberglass on it. The down side will come off smooth and you can even put down gelcoat first. Then cut to fit your exact size. I suppose you could frame your layup for the exact panel size you need. This way you could also embed aluminum bars in it, so you could have a structure to screw in shelf supports.

 

[jdecris]

Aerogel and Fiberglass panels

Questions:

Where did you get the Aerogel?

What did you use to seal the inside corners of the FRP (fiberglass) panels inside the box?

Thanks

 

[rslifkin]

or, if you want to save money, buy a big sheet of window glass, lay it on a sturdy table or a 4x8 sheet of plywood on two sawhorses, and layup the fiberglass on it. The down side will come off smooth and you can even put down gelcoat first. Then cut to fit your exact size. I suppose you could frame your layup for the exact panel size you need. This way you could also embed aluminum bars in it, so you could have a structure to screw in shelf supports.

Even cheaper, smooth plastic sheeting like they use for large trash bags laid over any hard surface will work. At least when working with epoxy, the finished product lifts right off, leaving a nice, smooth surface.

 

[Larry M]

We did the same thing on a sailboat we owned. We used white ABS to go over the foam. I don’t remember the thickness but it was probably around an 1/8”. It was flexible enough to get through top of the counter’s smaller door and very similar to the material on our home refrigerators and freezers.

 

[jdecris]

White ABS

What did you use to seal the inside corners of the white ABS you installed inside the box?

 

[Choices]

Go to my blog, grandbankschoices.

My freezer was a top load, same design. I tore it apart and you can see the photos of how it was built.

Saying that, I would not do what you are considering. If you want to reduce air volume just put milk jugs with water in them to freeze and keep it cold.

We keep three ten pound bags of ice in ours. Still plenty of room for groceries. But I like a lot of ice for my cocktails....

 

[Larry M]

White ABS

What did you use to seal the inside corners of the white ABS you installed inside the box?

If I remember, white RTV as per the recommendation from Dave Lehman, Sea Freeze. (We also had 2 of his custom units on our Krogen). I had heard, that one of his employees is back in the business locallly. If you can find him, he could be a good resource.

I liked working with the ABS for it’s flexibility. I made templates, dry fitted and installed. I used a polyurethane to hold the ABS to the foam since it stayed flexible and I wanted something that could expand and contract.

 

[Itwasntme]

Aerogel and Fiberglass panels

Questions:

Where did you get the Aerogel?

What did you use to seal the inside corners of the FRP (fiberglass) panels inside the box?

Thanks

Aerogel off EBay.
On the FRP, its not just sealing, you want it to be a strong joint. putting a few layers of tape on the outside corner will do that.

 

[BruceK]

Nigel Calder published a book called "Refrigeration for Pleasureboats", covers design, cabinet construction, linings,pretty much everything. Worth getting a copy if you can.