Insulation for machine

[G.Pope]

Has anyone tried to use low-pressure foam behind the box in pop machines? I would think that if you lined the back side with 1 or 2 mil plastic and wrap the box with the same plastic sheeting, install it and using longer hoses that can reach behind the box, and fill with the foam.
Wrapping in plastic would allow you to still slide out the box at a later time if you had to.

Has anyone done this and are there any pitfalls that I have not thought of that someone may have come across already?
Thanks

[loman4ec]

I have heard of a problem with this before. The problem is that it expands quite a lot. Much more than you can predict. If you spray it in you can really dis form the outsides of the machine and destroy any paintwork and body filler that you have done.

[G.Pope]

Your talking about regular foam. They make a low pressure foam that wont distort, or apply pressure to surrounding surfaces. The window industry uses this to foam in to the joints of newly installed windows without deforming them. As for it flowing out, slow and steady. You can always add more as needed. And you would have to wrap the outside surfaces for extra flow, but when its done, I think that the moisture that is inherent with fiberglass will be eliminated

[MoonDawg]

      Un-insulated houses have had insulation blown in between the walls so I guess
that is what you are comparing to? 
      Not sure if I understand what the advantage would be though.

[Marvin]

I don't know what type of R-value the spray foam has, but any new freezer or fridge has foam instead of fiberglass insulation.  It is also a very thin layer compared to waht is in the old soda machines.

Marvin

[rogerz]

It would be interesting to know what the difference in R value would be.
If you use an old round top machine all the time, they do run alot and the
loss of cold to the outside through the meatal is amazing.

tz

[G.Pope]

The reason I brought this up is that the PINK insulation will undoubtedly become wet over time. The condensation in the air gets trapped in the machine and transfers to the insulation were it gets wet and soggy and then loses its r-value over time. I have never opened up a machine to restore it and found wonderful insulation, and the bottom 12" were always the worst along with the metal.

The R-value of fiberglass is not great anyways. My next machine has a cavity of 2.5" to fill around the inside of the machine, meaning that the max. fiberglass can offer is R-7.5.

Flat sheets of styrene foam (foam coffee cup type) in the home centers are R-10 for 2.5"
(therefore it has a 33% better insulation factor to the Pink) and rigid and water proof and easily shaped. This is also what a lot of packing material is made out of, which would also be perfect to pour into the area and let it fill up.

Flat foam polyurethane sheets are R17 for 2.5" (therefore it has more than twice the  insulation factor to the Pink) and impervious to water also. Flat sheets would guarantee no expansion.
Anyone use this any of this stuff and had success?

[SIGNGUY]

I've only ever used r19 insulation... but guess never considered that when compressed it loses R value... interesting...

I think the low pressure expansion foam would work well, as long as it doesn't "push" the inner tub and outer cabinet to distort it like Josh said.

Whats it called? where available... and how much would you need to do a cabinet of an 81 or 39?

[G.Pope]

When you squeeze insulation, or pack it, the R-value is only determined by the width of the space. So, by using R-19 (6.25") insulation and packing it into a 2.5" space, that causes the trapped air spaces in the insulation to be removed and essentially becomes R-7.5.
DAP makes a low expanding latex foam. Problem is that if it gets wet for any length of time, it can break down and loose effectiveness, because it is water based.

Great Stuff makes a Yellow top window foam that is polyurethane foam and low expanding. Problem is that the stuff is terrible to work with. Get it on your hands and its on there for a week of more. This I know personally, as I have sprayed about 15 cans of this stuff over the past 3 years. I suggested using plastic to line the machine so it does not get on the metal. If you laid the machine on its back and sprayed a layer of foam, there would be plenty of time to push the inner box into position and let the foam start to travel up the sides.
I still think this is too messy.

extruded Polyurethane and Polyisocyanurate foam in the home centers is a very rigid foam that can comes in different thichnesses. So I might use a 1" and a 1 1/2" sheet (sandwiched to make 2 1/2") and cut to fit  the exact inside of the machine. No mess and easy to cut. Water resistant, wont break down and can be cut to fit any shape. Plus the r-factor is huge compared to Pink.

You guys dont paint your machines with paint from the 50's so why insulate with 1950's insulation.

[Pat Pixley]

Very interesting  it is something to think about for the next machine