G
Guest
Anyone know where to buy this these days, a friend told me Polyshield wasn't available anymore 
Thanx
Thanx
that work?
no.
no.
Bush Grower
Member
Yah.. FLIR still picks up the heat from the exhaust. I don't know if you've ever seen thermal images, but things like that stick out like a sore thumb.
green_tea said:
you should rape the first law of thermodinamic to achieve this.
yea you are!!!green_tea said:
yea they do...Bush Grower said:
here are a couple images ive snaged from the net, grow houses under flir.
U
ureapwhatusow
polyshield cant keep heat from passing through it even if it can block a heat signature
insulate a room in a room and use an split ac system, It shoudl read like a regular home cooling system
insulate a room in a room and use an split ac system, It shoudl read like a regular home cooling system
his statement is WRONG because of one KEY WORD, "hide"
you can hide heat very effectively. it was just said in the post above me.
FLIR only measures surface temperature.
these "reflective materials" may not "hide" it 100%, but when they say they reflect 97% of radiation, that means 97% of radiation is being reflected back. heat is radiation, light is radiation, anything on the electromagnetic spectrum is considered radiation. (IR, UV, light we can see, gamma, micro, etc etc etc) (keep in mind, white Paint doesn't reflect thermal radiation well)
If you read up on the material, most of them contain a layer or two of material to separate the sides, which acts like a room inside a room.
look at it this way... when you cook something in the oven at 400 degrees, and use aluminum foil, how soon after can you touch the foil? pretty much right as you pull it out. some of which has to do with the fact that it reflects heat, other part is that the thermal conductivity of the material is high (and its thin). that Aluminum foil may be 400 degrees, but it takes half a second for it to dissipate that heat into the air.
walls get hot because they have a low thermal conductivity rating, so after 8 hrs of light pounding radiation on it, the thing gets to a high temperature, and takes hrs to cool off.
your vents are ALWAYS going to come up hot, because you are pumping 130degree air through them 24/7... so the material heats up to 130 degrees... the material AROUND your vent is also going to get hot, because that metal vent is now transferring heat to any surface in contact with it on the other side... (be it your siding, roofing, concrete, air.. etc)
one more reason why making something to push the air outside through the lawn is a bad idea, your lawn will start to glow.
http://en.wikipedia.org/wiki/Thermal_conductivity
why is this even an issue, their video clearly shows whats going on... http://www.polyshield.ca/
Seriously though, HIDING is easy, its getting the HEAT out of the house undetected that's the hard part...
One more thing to solidify the fact that this stuff does work... how the fuck would you survive if stranded somewhere in the cold with one of those thermal blankets:
http://www.preparedness.com/emblan.html
oh man, reflects BODY HEAT??? isn't that thermal radiation!?
http://en.wikipedia.org/wiki/Infrared
go check that link too, read up on the "regions of infrared"
you can hide heat very effectively. it was just said in the post above me.
FLIR only measures surface temperature.
these "reflective materials" may not "hide" it 100%, but when they say they reflect 97% of radiation, that means 97% of radiation is being reflected back. heat is radiation, light is radiation, anything on the electromagnetic spectrum is considered radiation. (IR, UV, light we can see, gamma, micro, etc etc etc) (keep in mind, white Paint doesn't reflect thermal radiation well)
If you read up on the material, most of them contain a layer or two of material to separate the sides, which acts like a room inside a room.
look at it this way... when you cook something in the oven at 400 degrees, and use aluminum foil, how soon after can you touch the foil? pretty much right as you pull it out. some of which has to do with the fact that it reflects heat, other part is that the thermal conductivity of the material is high (and its thin). that Aluminum foil may be 400 degrees, but it takes half a second for it to dissipate that heat into the air.
walls get hot because they have a low thermal conductivity rating, so after 8 hrs of light pounding radiation on it, the thing gets to a high temperature, and takes hrs to cool off.
your vents are ALWAYS going to come up hot, because you are pumping 130degree air through them 24/7... so the material heats up to 130 degrees... the material AROUND your vent is also going to get hot, because that metal vent is now transferring heat to any surface in contact with it on the other side... (be it your siding, roofing, concrete, air.. etc)
one more reason why making something to push the air outside through the lawn is a bad idea, your lawn will start to glow.
http://en.wikipedia.org/wiki/Thermal_conductivity
why is this even an issue, their video clearly shows whats going on... http://www.polyshield.ca/
Seriously though, HIDING is easy, its getting the HEAT out of the house undetected that's the hard part...
One more thing to solidify the fact that this stuff does work... how the fuck would you survive if stranded somewhere in the cold with one of those thermal blankets:
http://www.preparedness.com/emblan.html
oh man, reflects BODY HEAT??? isn't that thermal radiation!?
http://en.wikipedia.org/wiki/Infrared
go check that link too, read up on the "regions of infrared"
ureapwhatusow said:
agreed (poly shield comment) but the beauty of it is that the differing layers help spread it out, to the point that there wouldn't be enough "heat" passing through to warm up your inside wall (then your 2x6's and insulation between them, and the air in there, and then finally your siding)
think about it this way, some of the radiation (is it a wave or a particle, or is it both!) will end up not being completely reflected by the material, the stuff that doesn't ends up heating up the material itself... but when the material is super thin, and is in contact with either a insulating material on one side (the middle layer stuff) or air on the other side (the air in your grow room) how fast do you think that material will be able to cool down? real fast, just like the aluminum foil in your oven.
We are talking basic undergrad / HS physics here... reflecting energy is not breaking any laws.
U
ureapwhatusow
green_tea said:
befret an education I can only state what woudl appear to me to be common sense
edit (I was thinging night vision) .. it reflects heat but cannot contain it
if it did they wouldlnt use a sheet in front of a light sources with no difference in the ambiant temprature between the source and the FLIR but they woudl make a box of polyshield and place it over a HID and let the ambient temprature of the environment on one side of the polyshield and the outside air vary by about 20 degrees like a normal grow and do their test
if you want to test it properties bake a potato at 500 degrees for an hour and wrap it in poly sheild and hold it in your naked lap.
If its 97% reflective of thermal energy the heat energy however will be only 15 degrees (3% of 500 degrees). My guess is it would burn the shit out of you in a short time, but I dropped HS physics so I only had to get to one class a day.
I guess i should have stayed in school so I can learn to be right
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GT- your reflectiviy statement is true, thats what makes it good though, because it reflects the light to the plants.
if the room is properly cooled the only thing u need to hide is the heat from the exhaust from your lights. but even that is getting found these days.
if the room is properly cooled the only thing u need to hide is the heat from the exhaust from your lights. but even that is getting found these days.
U
ureapwhatusow
I read the wiki it says not all heat is transmitted in the infrared spectrum so if polyshield refelcts infrared what about the other heat?
Infrared radiation is popularly known as "heat" or sometimes "heat radiation", since many people attribute all radiant heating to infrared light and/or to all infrared radiation to being a result of heating. This is a widespread misconception, since light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun only accounts for 49%[8] of the heating of the Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths.
but in the practical illustration on polyshields site, were they have infrared unit of supposed high quality
FLIR reads suface temps
In their demo there is a light and a strip of polyshield
the poly shield is ROOM TEMP
the light IS NOT
the FLIR reads the surface area of the light and then the polyshield and reports each substances surface temp
run an 80 degree room in a 50 degree house in the winter and there is heat exchange, polyshield helsp but does not eliminate heat exchange
Im not disputing the effectiveness of reflection, but its not 100% effective and depending on the scenerio may not be the only element required to arrive at a suitable solution
if the poly shield itself is 100 degrees does it read like its 50? i think it can reflect a certain differential in temprature but when the differential increases its effectiveness decreases.
The wiki on infrared , not all heat is trasmitted by infrared radiation, which is what polyshield reflects infrared, but infrared only.
Bottom line is if it reflects 97% of HEAT cause HEAT that it DOES NOT REFLECT enters what ever is behind the polyshield a simple experiment can be conducted
wrap a ice cube in polysheild reflective side facing out and put it in a bowl of water a few degrees above freezing. Will the ice cube melt or will the polysheild refelct the heat.
Infrared radiation is popularly known as "heat" or sometimes "heat radiation", since many people attribute all radiant heating to infrared light and/or to all infrared radiation to being a result of heating. This is a widespread misconception, since light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun only accounts for 49%[8] of the heating of the Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths.
but in the practical illustration on polyshields site, were they have infrared unit of supposed high quality
FLIR reads suface temps
In their demo there is a light and a strip of polyshield
the poly shield is ROOM TEMP
the light IS NOT
the FLIR reads the surface area of the light and then the polyshield and reports each substances surface temp
run an 80 degree room in a 50 degree house in the winter and there is heat exchange, polyshield helsp but does not eliminate heat exchange
Im not disputing the effectiveness of reflection, but its not 100% effective and depending on the scenerio may not be the only element required to arrive at a suitable solution
if the poly shield itself is 100 degrees does it read like its 50? i think it can reflect a certain differential in temprature but when the differential increases its effectiveness decreases.
The wiki on infrared , not all heat is trasmitted by infrared radiation, which is what polyshield reflects infrared, but infrared only.
Bottom line is if it reflects 97% of HEAT cause HEAT that it DOES NOT REFLECT enters what ever is behind the polyshield a simple experiment can be conducted
wrap a ice cube in polysheild reflective side facing out and put it in a bowl of water a few degrees above freezing. Will the ice cube melt or will the polysheild refelct the heat.
the only way these products provide "ir protection" ,if you could call it that, is via the light and assosiated heat from the light-waves not touching the walls... better yet it gets reflected to the plants.
you can still heat up a whole attic with an exhaust tube. the inside heat then is absorbed by the roof.
just grab a roll of mylar whats the issue?
you can still heat up a whole attic with an exhaust tube. the inside heat then is absorbed by the roof.
just grab a roll of mylar whats the issue?
G33k Speak
Member
Does the Polyshield demo show them reading from inside or outside the room??
I think Polyshield is snakeoil/bullshit.
I think Polyshield is snakeoil/bullshit.
there are types of shielding that do work if applied correctly. unfortunately, the u.s. government knows and the item is banned.
DIGITALHIPPY said:
That's what I'm saying here...
he said it was impossible to hide the heat... itsnot impossible to hide it, just hard as fuck to get it out of the house without it showing up on FLIR.
with regards to the not all heat is from infrared...
this is correct, heat is determined by the activity of the atoms themselves... the more they are moving around, the higher the temp... absolute zero the coldest temperature possible, is when the atoms themselves stop moving completely.
light energy is simply photons being bounced back and forth through the medium of atoms.
(ill stop here)
Since FLIR can only measure the far IR band... i would think that it wouldn't pick up heat generated by the other wavelengths...
nuclear radiation heats up things, but its a different kind of heat... If you took someone who had radiation poisoning, I don't think their temperature through a FLIR gun would be higher than normal (who knows i could be wrong)
when it comes down to it, if you completely cover a room with this stuff, and run AC in the room to keep the room at say 75degrees all the time, you will not be able to see anything outside the ordinary (not taking into account how you exhaust your heat)
if you keep your house at 70 24/7 and your room at 80 24/7, there is going to be a huge difference. But at the same time, as long as the vent is taken care of and cant be seen, a hotter room can be anything, computers, work out room, etc etc...
one more thing to add, mylar was made to reflect just the visible light spectrum I believe. where as this stuff has been designed from the ground up to reflect back as much thermal radiation as possible (just like the disaster blanket i linked too)
the thing that happens is when a light is near a wall without any mylar / poly the room may be 70 degrees, but that light energy that isnt being reflected back by the wall is getting absorbed by the wall, insulation and then your siding... and it will show up.
edit: also the fact that mylar / poly won't slowly warm up just from thermal radiation pounding on it is a huge benefit compared to a white wall.
(walls thermal conductivity is low, BUT at the same time, that means its really hard for it to dissipate that heat somewhere else.)
One of these days I'll be renting a thermal imaging camera.... If i can manage it, I'll talk to some fire buddy's to see if i can use the one they have on their Fire Truck. (you know to see any heat leaks in my house before winter gets here... haha)
OH one thing you CAN do is get one of those laser temperature devices, they are like 80 bucks maybe, and work almost identical to FLIR, but instead of having 600pixels by 400 pixels updating 30 times a second, its 1 pixel by one pixel updating whenever you push the read temp button!
the thing that happens is when a light is near a wall without any mylar / poly the room may be 70 degrees, but that light energy that isnt being reflected back by the wall is getting absorbed by the wall, insulation and then your siding... and it will show up.
edit: also the fact that mylar / poly won't slowly warm up just from thermal radiation pounding on it is a huge benefit compared to a white wall.
(walls thermal conductivity is low, BUT at the same time, that means its really hard for it to dissipate that heat somewhere else.)
One of these days I'll be renting a thermal imaging camera.... If i can manage it, I'll talk to some fire buddy's to see if i can use the one they have on their Fire Truck. (you know to see any heat leaks in my house before winter gets here... haha)
OH one thing you CAN do is get one of those laser temperature devices, they are like 80 bucks maybe, and work almost identical to FLIR, but instead of having 600pixels by 400 pixels updating 30 times a second, its 1 pixel by one pixel updating whenever you push the read temp button!
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G33k Speak said:
the demo clearly shows the following:
light in room
FLIR imager
then they take untreated polyshield and put it between light and FLIR imager.
you can see the heat from the light from the FLIR.
they then take a treated polyshield and put it between the two, and it looks just black, probably the temp of the polyshield.
the HUGE thing wrong with this is that between the FLIR and treated polyshield there would be a house... but they are trying to show you that none of that radiation is getting through to even hit the house.
I'm not going to lie, that video is shit, and I really wish I had the money to do it myself.
EDIT: I keep posting in a row, so sorry, i just get a train of thought and go research it...
with that in mind I present you the most important piece I've found so far:
http://en.wikipedia.org/wiki/Thermal_imaging#Emissivity
Emissivity is "a material's ability to emit thermal radiation."
So i would assume that what you do is make the material have a layer of material that is lower than low on the table of emissivity.
Aluminum is something like .02 based on the table in the links on that page.
Concrete is like .9... wood is like .8
closer to one, the material likes to emit a lot of radiation.
the goal of the material would be two fold:
reduce the heat signature by going from high to low every other layer...
since the cop using the FLIR device doesn't know about the material in there, he can't compensate for something like this.
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