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Source of reflective tape..

post #1 of 20
Thread Starter 
I want to try reflective tape to see if it will help with cold toes...


1) is it as simple as putting tape on the bottom of the bootboard - silver side to the 'snow' side?

2) can I use any metallic tape - 'muffler' tape (easy to get at the autoparts store) - or HVAC 'metallic' tape - or is there something specific that works better?

Any other comments welcome.
post #2 of 20

- Other way 'round: shiny to toes.   The toes are the source of the infrared radiation you want to reflect.

 

 

- Mylar tape (no metal in it), think space blankets and shiny balloons.

 

 

post #3 of 20

I used some spray adhesive and some kitchen variety aluminum foil, spayed the bottom of my footbeds glued the foil trimmed the edges.  Dont know if it helped or not, but it was free and easy.

post #4 of 20
Quote:
Originally Posted by Richie-Rich View Post

I used some spray adhesive and some kitchen variety aluminum foil, spayed the bottom of my footbeds glued the foil trimmed the edges.  Dont know if it helped or not, but it was free and easy.

 

Aluminum is a nice reflector for infrared radiation, but it also nicely conducts heat.  :)

post #5 of 20
Quote:
Originally Posted by comprex View Post

- Other way 'round: shiny to toes.   The toes are the source of the infrared radiation you want to reflect.

 

 

- Mylar tape (no metal in it), think space blankets and shiny balloons.

 

 

 

Don't forget grow rooms.

post #6 of 20
Quote:
Originally Posted by comprex View Post
Quote:
Originally Posted by Richie-Rich View Post

I used some spray adhesive and some kitchen variety aluminum foil, spayed the bottom of my footbeds glued the foil trimmed the edges.  Dont know if it helped or not, but it was free and easy.

 

Aluminum is a nice reflector for infrared radiation, but it also nicely conducts heat.  :)

Yes, this is why you cant allow for the "heat shield" to actually touch the heat source.

post #7 of 20
Quote:
Originally Posted by Richie-Rich View Post
Quote:
Originally Posted by comprex View Post
Quote:
Originally Posted by Richie-Rich View Post

I used some spray adhesive and some kitchen variety aluminum foil, spayed the bottom of my footbeds glued the foil trimmed the edges.  Dont know if it helped or not, but it was free and easy.

 

Aluminum is a nice reflector for infrared radiation, but it also nicely conducts heat.  :)

Yes, this is why you cant allow for the "heat shield" to actually touch the heat source.

 

? How did you insulate the Al from the liner?  Spray glue?

post #8 of 20

Well, no your feet are the source of heat, so the foot bed itself acts as a decoupler/insulator.  I put the AL on the bottom of the foot bed so my feet are not touching it...even if it were I would think the socks alone would offer the insulation needed.

 

When installing heat shields in a car they always say to leave an air gap and to not allow the shield to touch the heat source.

post #9 of 20
Quote:
Originally Posted by Richie-Rich View Post

Well, no your feet are the source of heat, so the foot bed itself acts as a decoupler/insulator. 


 

If it was a perfect one (i.e. the bottom of the footbed never got warm from the feet, warmer than the snow anyway) then you wouldn't -need- the reflector.

 

You can prove to yourself that the footbed itself blocks IR radiation from the foot by putting the footbed directly in front of an infrared remote control.

 

You just made a (shiny!) heat sink, bud.

 


Edited by comprex - Tue, 03 Feb 09 00:17:15 GMT
post #10 of 20

 heres a product that insulates well, you would want to put it under your foot bed so as to not itch your foot. Its high insulation property and very flexable and light weight. this site is just so you get an idea of what it is not a suggested place to get it. If you look in your area for a ceramic supply house for home kilns and such they should have it or be able to get you some.

If you can't find it in small enough quantities for this use PM me and I can probibly help you out.

ablerefractory.com/able_supply_stocks_ceramic_fiber.htm

My feet stay warm without anything so I have never used it for this purpose,but I do know you will not find a better insulation this light and flexable

Hope it helps


Edited by Old Boot - Tue, 03 Feb 09 02:30:20 GMT
post #11 of 20
Quote:
Originally Posted by comprex View Post
Quote:
Originally Posted by Richie-Rich View Post

Well, no your feet are the source of heat, so the foot bed itself acts as a decoupler/insulator. 


 

If it was a perfect one (i.e. the bottom of the footbed never got warm from the feet, warmer than the snow anyway) then you wouldn't -need- the reflector.

 

You can prove to yourself that the footbed itself blocks IR radiation from the foot by putting the footbed directly in front of an infrared remote control.

 

You just made a (shiny!) heat sink, bud.

 


Edited by comprex - Tue, 03 Feb 09 00:17:15 GMT

That did cross my mind.

post #12 of 20

Not to put a damper on the IR radiation theory

but as you can see IR radiation untill a temperature of about 1400F is achieved has very little effect on the surface of witch it is opposed to,and the lower the temp below 1400f the smaller the change will be. This being said a surface at 100F will have no noticable effect upon an opposing surface

 

HEAT TRANSFER RELATIONSHIPS

Conduction

Q

= kA (t1-t2)

Convection

Q

= fA (t1-t2)

Radiation

Q

4

4

1 + 1 - 1

P

= AK (T1-T2)1 P2

Q =heat transferred, Btu/hr

A =surface area across which heat is

being transferred, sq. ft.

t

t

L =thickness of object through which heat

is conducted

k =conductivity of material, Btu-ft

hr-sq ft-°F

f =convection film coefficient, Btu-ft

hr-sq ft-°F

K =Stefan-Boltzmann constant,

=.1724 x 10

1 =temperature of heat source, °F2 =temperature of heat receiver, °F-8 Btu/sq ft-hr-(°R)4

P

P

T

T

(°R = °F + 460)

1 =emissivity of heat source2 =emissivity of heat receiver1 =temperature of heat source, °R2 =temperature of heat receiver, °R

THERMAL PROPERTIES OF VARIOUS MATERIALS

Solid Latent Liquid Latent

Density Specific Melting Heat of Specific Boiling Heat of

Lb/Cu Ft Heat Point, Fusion, Heat, Point, Vaporization,

Material @60°F Btu/Lb-°F °F Btu/Lb Btu/Lb-°F °F Btu/Lb

Acetone – – -138 33.5 0.530 128-134 225.5

Acetic Acid 65.8 0.540 62.6 44 0.462 244.4 152.8

Air .0765 – – – 0.237 -311.0 91.7

Alcohol-Ethyl 49.26 0.232 -173.2 44.8 0.648 172.4 369.0

-Methyl 49.6 – -142.6 29.5 0.601 150.8 480.6

Alumina 243.5 0.197 3722 – – – –

Aluminum 166.7 0.248 1214 169.1 0.252 3272 –

Ammonia 32° 45.6 0.502 -83.0 195 1.099 -37.3 543.2

Radiation Losses:

Radiation Losses

Rate x Shape Factor. See page 49 for radiation rates. Assume

a Shape Factor of 1.

= Opening Area x Black Body Radiation

350

300

250

200

150

100

50

0

Heat Transfer Rate, Btu/Sq Ft x 1000

1000

1500

1800

2000

2200

2400

2600

2800

3000

3200

°F 60°F°F°F°F°F°F°F°F°F°F

Receiver (Colder) Temperature

L

post #13 of 20

Not doubting you but then would you say those thermal rescue blankets made of reflective mylar don't work?  Or rather the way in which they work is simply shielding the person from ambient air, not because of the reflective properties of the deposited metal?

 

Where's Garret, I know he loves this kind of stuff.

post #14 of 20

I have been trying to download some information for you from my works intranet but am meeting with some fierce resistance as it is protected information.

you can look at the site allowed to the public at eclipsenet.com. Unfortunatly I cant get you access to our internal schooling tonight but can try to get it for you tommorow.

Thermal properties section and heat transfer if I can get you access to them will explain it well. but basically it has to do with materials ability to absorb and reflect heat Specific heat is the amount or heat required to raise the temp of a unit weight of the material one degree. The higher a materials specific heat ,the greater its heat content at any given temp. Not all heat obsorbed relates to a change in temp.

Latent Heat of transformation is a property of materials.  It is the amount of heat required to change the state of a unit weight of material. Changes of state include; Melting and freezing......Boiling and condensation...changes to the crystal structure.

There are 2 types of transformationsthat absorb heat Reversable and Non-reversable the heat absorbied during melting boiling or crystal structure change will be given off if the process is reversed.  But if the heating process causes a chemical reaction to occure ,not all of the heat absorbed will be returned in cooling.

 

The heat trasfer of the material and the color of the material play a part in absorbing or reflecting heat as well.

 

I will follow up with it tommorow or the next day if you really want to know or cant find it on our site. let me know but I have to snooze right now for the night

post #15 of 20

I have been listening to Old Boot fret over this most of last evening.  I explained what he says, just doesn't make sense to me, the lay person.  Was he telling me thermal blankets don't work?  Well I think i have a lay person explanation now.  The really short form is, they are not made of an aluminum conductive material, but of a reflective, non breathable, insulator, that will trap heat in and release it more slowly then nothing.  He feels if tested in most cases they would be marginally better then a plastic bag (I'm writing myth busters with that).

 

Thermal Blankets work to retain/trap heat in air, which is the insulator.  Or you can purchase an advanced thermal blanket with a ceramic backing and reflective outer surface to keep high heat of parts and components that could be damaged by such. The outer surface would reflect the heat away and the inner insulation properties would keep it off the equipment.  This is not infared heat, it is heat transferred through convection. 

 

Heat moves from Warm to Cold.  So a conductive material touching something will increase the movement from Warm to Cold.  But if you were trying to hold heat in, a non breathable material with an insulative value and air (or material holds air also), would slow down the conductive movemet from Warm to Cold (retaining more heat inside).  A non breathable material trapping more in.  But this material would never be Aluminun on its own as this would conduct the heat out faster.  It could however be materials mixed to an alloy that would refelect with aluminum.

post #16 of 20

Oh yes and one more point to the orginal question.  Thermal Tape is typically used to conduct heat (disapate heat) faster from a source to the surrounding air.  Such as in a computer when it is used to help dissapate the heat created in the CPU to the ambient air in your tower.

post #17 of 20

There are different ways of transfering heat. Radiative, conductive and convective. they all play a part in a non-vacuum environment like you ski boots. The thermal blankets work by reflecting back IR radiation (300°K temperature for a human body) slowing radiative heat loss. They are made of aluminized Mylar. The aluminum layer is very thin. This is very similiar to a layer of Multilayer Insulation (MLI) used on spacecraft. In this case the plastic material might be Kapton with gold or other thin film coatings. They do work. Firefighters are issued similiar thin thermal shields for emergency use and they have saved lives. If you have windows with Low E coatings these function in a similiar manner. They have a thin metalic coating to reflect IR energy back into the room and prevent heat loss.

post #18 of 20
Thread Starter 

So short of using reflective kapton - results would be marginal at best, even with the reflective kapton..

post #19 of 20

So bottom line, if one were to have an aluminized sole, that is not in direct contact with the foot (insulated by the footbed and sock) is it a benefit, detrimental, or of no consequence?

post #20 of 20
Quote:
Originally Posted by Richie-Rich View Post

So bottom line, if one were to have an aluminized sole, that is not in direct contact with the foot (insulated by the footbed and sock) is it a benefit, detrimental, or of no consequence?

 

IMO, no real consequence, the liner is too good an insulator.   Maybe a slight antibacterial effect

 

But why not make the experiment yourself?    Get stock cardboard footbeds, aluminize one, put them in the boots and stand on  buckets of ice (not snow, it's too good an insulator.).     

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