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Polystyrene Sheet Insulating


smidey

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Yesterday i went into Payless plastics to get a poly box & i saw polystyrene sheets there so i bought a 1200x1200x12.5mm sheet which was only $9. I cut it up & lined the back & sides of my two grow out tanks that are in my very cold garage. I had noticed since it got cold that the heaters were on every time i went into the garage so to help keep the warmth in poly lining them would be a great idea. This morning when i went to feed the fish I touched the poly & it was kinda warm which makes me think it is not thick enough to insulate the tank well. Anyone know more about the thickness required for optimal insulation or how well the 12.5mm will work?

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I think some of the insulation websites have listings of all the different grades and what they are recommended for, google it? Thats probably not much help sorry.

I'm looking at getting 40mm underfloor polystyrine for around my tanks, it seems quite thick and is cheap on that auction site but interested to hear what other people say about the thickness needed. I'd imagine the thicker the better, maybe another thicker sheet behind the one you've got?

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Me and Joliet got a Platty off a member on here (Sorry mate, I've forgotten your name), and when we went to pick it up he gave us a huge roll of Hot Water Cylinder insulation foam. It's soft on one side, and plastic on the other, and it's really good at insulating. He had it covering the back of his 300 litre tank and said it certainly helped with his power bills in the winter. May want to have a look around for some :].

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This morning when i went to feed the fish I touched the poly & it was kinda warm which makes me think it is not thick enough to insulate the tank well. Anyone know more about the thickness required for optimal insulation or how well the 12.5mm will work?

Any at all will insulate the tank. A sheet of paper will insulate the tank. The question is how much. And even just 12.5mm will be significant.

I agree with Weka, it's unlikely the temperature of the poly is much above room temperature, hands are absolutely useless as thermometers. A 26° steel plate will feel cold next to a 20° piece of wood...

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Any at all will insulate the tank. A sheet of paper will insulate the tank. The question is how much. And even just 12.5mm will be significant.

I agree with Weka, it's unlikely the temperature of the poly is much above room temperature, hands are absolutely useless as thermometers. A 26° steel plate will feel cold next to a 20° piece of wood...

Sorry , off topic, but Ira How do you make the little degrees symbol??

I dont know how.

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i know that it will have an insulating factor, its just how much or how effectively it insulates. polstyrene must have a percentage of air in it so the temp of the tank will heat that air increasing the polys temp with it. where the tanks are it is almost the same temp as outside & the poly was definately warmer than the room.

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wow, there is alot of really technical info on the net about it but here is some info thAt can help us understand, i take form this info below that the lack of heat transfer the better it insulates but i am not totally sure that "Koolfoam" is the standard polystyrene.

FROM KOOLFOAM WEBSITE

The polystyrene walls occupy only about 2% of the total volume: the rest is air which is trapped in the cells and cannot pass from one cell to another. Still air is an extremely poor conductor, so that little heat can move from one cell to another and the alternative paths along the thin polystyrene cell walls are equally unsuitable for rapid heat transfer.

The thermal conductivity of cellular materials made from Koolfoam varies with density, and with temperature. Within the normal density range of material used in building the variation of conductivity with density is comparatively small.

At 10°C the thermal conductivity of expanded Koolfoam of density 20kg/m is 31-36 mW/m.k. However, in carrying out insulation calculations for heated buildings it is usual to use the same nominal value for all densities and temperatures, eg the value of 30 mW.m.K.

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Sorry , off topic, but Ira How do you make the little degrees symbol??

I dont know how.

:bounce: good on ya for asking! (and Ira for answering) I think there were perhaps quite a few of us who just learned something ;)

It has been driving me nuts for a while, not knowing where to get the ¢ and £ symbols, just for starters!

It's interesting how we assume some things which we learned long ago are "common knowledge", and can be quite funny when discovering differing spheres of knowledge.

PS. Good luck with the insulating, Smidey. That poly has got to be helping!

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