Which closed cell Foam for fridge re-fit?

[sharpey]

Hi all,

I would like to know if anyone has ever used versifoam before to do fridge insulation works...?

What I like
1) expands within 1 minute
2) once expanded up to 3 more inches can be added on top without waiting for full cure
3) full cure achieved in 15mins
4) low pressure
5) +/- 90% closed cells

What I don't like
1) cost... it's kind of double the price here as it would be in the states. The system 9 kit would set me back 500USD

here is the datasheet http://www.rhhfoamsystems.com/upload...20Standard.pdf

My other alternative is a construction 1 can system data sheet here https://www.denbraven.com/en/product...datasheet.pdf/

what I like

1) cheaper.. by a fair margin... 1 can can be had for about 15USD
2) more readily available

what I'm not so sure on

1) 70% closed cells (is this acceptable?)
2) not a low pressure foam, so needs more care when applying
3) takes longer to expand and cure, so harder to gauge how much to spray


Sorry if it seems like I'm answering my own questions here.... the TLDNR version is basically,

1) What % of closed cells is enough? Will 70% cut it for fridge insulation, or do I need more?
2) is there any way to tell if both systems will give a similar r-value given 4inches of insulation around the fridge shell.

Cheers,

James

[sharpey]

So, not a terrible idea then?

I do appreciate opinions

[Waterrat10]

Originally Posted by sharpey

So, not a terrible idea then?

I do appreciate opinions

They both would work. You could paint the cheaper foam to reduce possible water absorption. How much access to the area around the fridge do you have? How much space. The cheaper stuff is about R value of 6 per inch/2.54 cm. You would want 2-4 inches or 5-10 cm. Can you acquire Polyiso or EPS foam? Cutting and gluing either of those foams would also be good options.

Seems like the PU foam would be a little slower instillation but 15 bucks vs 500 bucks seam like it would be worth your time. Just use a little spray paint on the outside after cure to reduce absorption from humidity in air.

[ErikFinn]

Originally Posted by Waterrat10

Just use a little spray paint on the outside after cure to reduce absorption from humidity in air.

Some people have suggested glassing over but isn't that quite laborious also? Spray painting sounds easy, any requirement for the paint? Or how about the liquid sprayable rubber? ( I forgot the brand )

[UNCIVILIZED]

Why would you not use sheet foam for the majority of the project, & then use spray foam for the hard to reach areas, as well as to seal all of the joints in foam sheeting?

And with sheet foam you could pre-coat it with a thin layer of glass & pigmented epoxy. So that once things were assembled, you'd just need to tape the corners & joints, non?

Also, even if you don't go with sheet foam, you can use pre-fab fiberglass sheeting to make flat surfaces & other components out of. Including taping them together at their corners in order to make a box.


PS: If you paint things, it'd likely be wise to add an anti-mildew agent to the paint. As fridges can get pretty gross. So anything which will stop or slow down such, is probably a good thing. But read the MSDS, etc. first, to ensure that it'll be food safe when cured.

[Waterrat10]

I should of asked a few more questions. Is this all hidden or will you have to look at it? Based on Uncivilized comments it makes me wonder if you are putting this inside your ice box. If that is the case 70% open cell is not good and paint or rubbery stuff wont cut it. EPS or Polyiso would be much better in or out. R20-30 would be best depending on room and access more is better and you could use some of that metallic silver duct tape for the seams. Uncivilized comments are a bang up job but I did not hear that kind of motivation in your post. Expand on where and how if you would?

[UNCIVILIZED]

Thanks for the kind words.
There's also another technique which comes to mind for building with foam. And that is to laminate a thin fiberglass skin onto one side of the foam, while producing a smooth surface on the glass. Then you kerf the foam on the other side as needed so that you can bend the panel to conform to different radii (curve diameters). Followed by locking the curves in place by filling in the kerfs with foam or putty, & then laminating a skin overtop of same.

[SV THIRD DAY]

From an R-value, bang for your Buck, and ease of install here is what I would recommend:

1. Polyisocyanurate (R-Max) 4ft x 8ft 1" thick boards from Home Depot
Thermasheath Rmax Thermasheath-3 1 in. x 4 ft. x 8 ft. R-6 Polyisocyanurate Rigid Foam Insulation Board-787264 - The Home Depot

2. Foil tape to act as a nice vapor barrier over the cut panel pieces of PolyIso
Nashua Tape 1.89 in. x 50 yd. 322 Multi-Purpose HVAC Foil Tape-1207792 - The Home Depot

3. Fiberglass wall board cut to fit as a nice clean new liner for your Box
Decorative Paneling - Paneling - Â*The Home Depot

4. 3M 77 Contact adhesive to attach all the puzzle pieces together
Search Results forÂ*3 m. super 77Â*at The Home Depot

Then for the seams, you can get fancy with epoxy or easy with 3M 4200.

It sounds like a pretty difficult project, but only if you make it one.

The ideal would be to make the box between an R20 and R30 thickness, and the PolyIso is 6.5 per inch.

Good luck amigo...

[Terra Nova]

SV--good post. Lots of ways to skin that cat. I will point out that those pre-cast fiberglass panels are of a very low structural grade (you can easily break it in your hand) which is quite easy to damage unless applied to a substrate stronger than insulating foam; ie a thin layer of plywood, for stiffening the fiberglass and for holding screws used to hang shelf cleats, evaporator, ...etc.

UN--I would not use anti-mildew paint in food storage.

[SV THIRD DAY]

Great point, screwing into thin FRP and Polyiso will need some preplaning for backing support and paint around food? Only if it is Food Safe, which most antimildew paints are not. You don't want your Box to be a Toxic Zone.

[newhaul]

OK all great info on this thread and I feel that the 70% will be just fine for the project that the op is asking for assistance with except I would just use the expanding foam in areas that you can't get ridgid panels into and to fill in gaps. Lastly using the flex seal as a waterproof coating will be great as well.
This recommendation comes from rereading his last statement that says it would be on the outside of his enclosure.

[sharpey]

Hey, thanks for all your replies...

I admit I could have been more clear...

https://goo.gl/photos/u79WdgvyDTYK7BKV7

As you can see in this pic, my engine and fuel tank are out... The fridge cabinet is to the right of the gaping bilge gunky hole (the woodwork is slightly obscured by the step ladder)...

A carpenter is supposed to be removing the cabinetry, so I assume I'll have some access to the fridge box, but due to the stove being next to the fridge on one side, and the lazarette wall to the rear, I wont have perfect access to the box...

I'll take some more pics once the woodwork has been opened up....

And yeah, essentially, I want a system that isn't going to be too involved in terms of prep and finesse like cutting and taping... The foam, though expensive, it seems to me would be a one stage fix... spray and be done with it.

Cheers,

James

[senormechanico]

Polyisocyanurate foam is hygroscopic...

[SV THIRD DAY]

Originally Posted by senormechanico

Polyisocyanurate foam is hygroscopic...

Chat Room Rumor Alert 101....

While YES...Polyiso is hygroscopic what does that mean in the real world and should we run away screaming with our hair on fire? No...not in my opinion anyway, but other are free to call me crazy.

Polyiso has a water intrusion rate of 1/4" per year when sitting in water, but who would redo a box and let that happen? The death alert of "it's hygroscopic" while true is somewhat meaningless if you use the material properly in your build to keep water away from the insulation. Polyiso comes encased in a water proof foil layer. So if you use foil tape to cover the cut edges you have a great vapor barrier that will keep you Polyiso insulation nice and dry. Then when that is covered with your water and vapor proofing materials, it pretty well protected from the evils of water ingress.

If some want to use a hydrophobic insulation (like blue board) that has a 33% lower R-value (meaning your walls need to be 1/3 thicker for the same R-value) out of a panic over the words hygroscopic vs hydrophobic, then they can...but they at least need to make the decision with all the facts in hand. Some cruisers are limited on space for their insulation, so they would rather use a better R-value insulation and just take the proper build steps to keep it dry that be scared away by buzzwords.

[jamhass]

James:

Worth paying extra attention to the two or three areas with greatest heat load: side facing the engine compartment, side facing the stove/oven, and if the hull is one side, there also, as sunlight can really warm things up. These areas can particularly gain benefit from both: 1) a bit of extra insulation, and 2) a radiant barrier -- the foil tape as Rich suggested is perfect.