Blown Foam Insulation

[Bones]

I'm rehabbing a WH-12T chest cooler and am thinking about replacing the fiberglass insulation with a more efficient closed cell spray foam insulation. I'm wondering if anyone has done this before and if they could recommend a product. Having worked with "Great Stuff" and other products like it, I know the stuff can be difficult to work with, particularly if I'm trying to fill a cavity between the liner and the body of the cooler. I'd prefer to line the area to be filled with thin plastic sheets so as not to lock the entire unit solid with the foam. I've seen some products for use in construction applications, but fear it would be difficult and messy to try to shoot the product into the thin space I'm trying to fill.

Any thoughts, comments, or recommendations appreciated.

[coke_and_stuff]

I personally would not do this, If you ever had to break that liner out again you wouldnt be able to, also you could actually stress the outside metal on the cabinet and cause it to bend out.

Joey

[Bones]

Yeah, I agree on wanting to preserve the ability to get the liner out at a later date. That is why I would want to line the foamed area with plastic, so as not to glue the whole thing solid. I thought about filling a large garbage can bag, a very thin one, with the foam while positioned between the liner and cabinet. Then the foam would expand to fill the space, but would be contained within the bag. This way, there would be no adhesion to the cabinet or the liner. I could still slide the liner out as it would have the bag between it and the foam. That's the theory anyway. It may be difficult to do.

[collecture]

How would you get insulation under the liner? I'd stick with traditional fiberglass. If you want to spend the bucks, you could put rock wool in there.  

[Bones]

For under the liner I was thinking about the extruded polystyrene board (the pink board or something similar that you can get at Home Depot). There were styrofoam pieces under the liner to support it and prevent the fiberglass from being crushed. It is about 2 1/4 inches thick. So if I had that for a base, I was thinking of shooting each of the four sides separately within the bags I described above. If the bags are thin enough, like most of the cheaper garbage can liners, the foam should have no problem expanding to fill the cavity. I don't think the expansion would be anywhere near enough to bend the cabinet metal walls. Any over fill would likely come out the top along the edge of where the liner and cabinet come together. This area should easily be trimmed after the foam cures. I do worry about voids in the area I'm trying to insulate if I don't get the material deep enough and the foam doesn't expand to the degree necessary to completely fill the area. If my method works, I could remove the liner after the foam cures and check for voids. But if I screw it up, I'll have one hell of a mess.

Sounds like no one is aware of anyone doing this. I'll continue to monitor for other thoughts.

Thanks for your questions and suggestions.

[Bones]

Check out the video under "Slow Rise Closed Cavity Video" on this site. This is one of a few different products I've found. Don't know if its the best option, but it gives you an idea of what I'm thinking of.


Slow Rise Closed Cavity Video

It doesn't look that difficult.

[Creighton]

First off welcome to the board! Unless that machine is going to be in some extreme weather conditions I see no value in injected foam.  Normal insulation should be fine with no headaches down the road.
Just my thoughts...
Creighton

[loman4ec]

I agree with creighton. I replace the insulation in all of the machines I build and I always use regular insulation. I have never had a problem. It is also cheep and easy to install.

[sodaworks]

I concur!!

[Bones]

Thanks for all the great feedback, its appreciated.

It seems that all agree that fiberglass works fine. But I can't help but think that you don't see fiberglass in new refrigerators or freezers these days, its all foam injected. I suppose it comes down to a cost/benefit analysis. The foam is more expensive than fiberglass for sure, but it also has an R-value twice as high as fiberglass. Blown in place foam is R-6.25 per inch, while fiberglass is only 3.14 per inch, so in theory, my compressor will run half as much if I use foam as compared to fiberglass. Ease of installation would also be a factor. Foam would be much more difficult to install. I also like the idea of the closed cell characteristics of the foam, which would not lose its insulating characteristics if it becomes wet. I keep my cooler in the garage, and on hot & humid summer days I worry about condensation. When I disassembled the unit, I did detect areas where condensation occured. I suppose if I make sure the cabinet and liner are well sealed, I can avoid that.

Thanks again for all the thoughtful comments.

[davethebirdman]

Hey Bones

If you did decide to go against the advice here you could always post your results.
You may have stumbled upon something that cuold benefit the group as a whole.

Having got covered in fibreglass and annoyed the wife all night long with itching I'd still
go with it over foam.

Let us know how you get on.

[dr galaga]

(Bones @ Sep. 23 2006,2:26)

QUOTE

so in theory, my compressor will run half as much if I use foam as compared to fiberglass.

You have to remember that there are a number of other areas that "warm air" can enter from like the can/bottle doors and the condensation hose.  I don't think you will get double the results.  In my opinion, modern consumer refrigerators will not last as long as your soda machine, they are not ment to be broken down like soda machines and they also use the foam so that they can make the cavities smaller (either for more room inside, or less sheet metal outside).  
Just my 2 cents worth on this topic!  '>

[Bones]

Whatever the outside factors are to turn my cold air to warm air, they are the same regardless of what insulation I use, and I would think that having insulation with twice the insulating properties as another should be pretty significant. You're probably right that its not going to result in my compressor running half the time, but I suspect it will help quite a bit. Most of the time it sits without much opening and closing going on. I suppose theoretically, if you had a huge R-value of 1,000 and increased it to 2,000, the added benefit wouldn't be double. At some point added R-factor probably doesn't matter much. I'm going to continue to give it some thought. I'll let you all know if I try it and how it comes out. But thanks again for all the well informed feedback.

Unfortunately, I have a more pressing problem. While working on my refrigeration unit I detected a slight hissing sound near the evaporator coil. I think I sprung a leak where the copper lines connect to the coil and I probably lost my refrigerant. Anyone know if it's possible to find R-12 these days? I'd prefer not to replace the system. Bummer  '>

[coke_and_stuff]

R-12 is around, I know where a bunch is but its not for sale.

Joey

[bubba]

(coke_and_stuff @ Sep. 24 2006,7:22)

QUOTE

R-12 is around, I know where a bunch is but its not for sale.

Joey

Is it for free???   '>

[coke_and_stuff]

No its not going anywhere sits up on a shelf, something like 2,000 lbs all together crazy amount. he uses it for his old cars and bought as much as he could when they started phasing it out.

Joey

[Bones]

Well, after thinking about all the advice, and weighing the costs and my concerns about working with the expanding foam, I decided not to pursue it. I did, however, find what I think is a pretty good middle-ground solution.

First of all, for the base under the liner, I used 2 1/4" inches of polystyrene foam board (Pink Board). The original insulation there consisted of 4 white strips of styrofoam that supported the liner and acted as spacers between the liner and the sheet metal panels that rest on the frame supports. The fiberglass was packed between the styrofoam spacers. With solid polystyrene board, I have better support, and a higher R-Value (about 11.25). I ran this board across the entire floor area tight to the curved walls of the cooler.

For the two short sides, I cut 1 1/2" polystyrene boards to fit under the top lip of the cooler body and then swung the bottom from the inside out to make a tight fit with the bottom board. These two side boards also were cut to snug up to the curved inside walls of the cooler body.

For the front and back, I also used the same technique of fitting the polystyrene board under the lip of the top opening and swinging the panel to fit tightly with the floor. These boards were square as they didn' t come up against any round edges of the cabinet. They only touched the top lip of the box and the floor and side polystyrene panels.

After fitting all 4 sides, I had a square cavity that was the same size as the outside dimensions of the liner.  Before installing the liner, however, I removed all 4 side panels and cut 3 1/2" fiberglass insulation batts to fit behind the polystrene panels to fill the cavities between the metal cabinet and the polystyrene panels. Then I reinstalled the polystrene. I then slid the liner into the cabinet. The fiberglass behind the polystrene created some pressure on the polystrene against the liner, which made for a nice tight fit. I now have 1 1/2" of polystyrene against the liner, with an R-Value of 7.5, backed up by 3 1/2" of fiberglass with an R-value of 3.75, for a total R-Value of 11.25 throughout the cabinet. The closed cell polystyrene also provides protection against any infiltration of moisture.

I haven't done the top lids yet, but will likely use fiberglass there due to their irregular shape.

Thanks again for everyone's recommendations. This is a great forum for questions.

[Bones]

I meant to say the fiberglass is 3.75 R-Value per inch, so a total R-Value of R-13 for the fiberglass and R-7.5 for the polystyrene, for a combined R-20.5 for the cooler walls.