Temp. Guns , WTF ???

[DWncchs]

What makes them so finicky ? Some days I'm really impressed with what you can do with them (like finding a dead cylinder by shooting the exhaust manifold) and then other days they just act stupid.
Short story...we bought an old park model trailer in Fl to use as our winter getaway (snowbirds) and I'm working on the roof. Got all the leaks fixed and moving on to different roof coatings for standing up to the Fl sun and reflectivity.
At the present time I've set up different surfaces and colors on the roof. Here is my situation. The roof is new roll roofing coated with silver dollar roof coat except for my test area's where I have left some roll roofing uncoated,some coated with black tar roof sealer and some coated with water based white elastomer coating.
temps.
black tar roof-- 160
uncoated roll---150
silver coated---125
white coated---125 ....???
If I put my hand on the black it will burn my hand,the silver is very hot but the white is almost cool in comparison.
Why ? Is the white "really" the same temp as the silver and for some reason doesn't transfer the heat to my hand ?

(Bottom line I want less heat coming through the roof into the ceiling of the trailer but with the heat gun I can't seem to see ceiling temp differences inside the trailer,but in reality the inside test is flawed because the diff colored areas are to small to make much difference.)

 

[big_G]

White reflects heat energy and black absorbs heat energy. Our school buses in Texas have white roofs. I don't think this holds true in the dark, as the absorption is from mostly from the light spectrum.

 

[GT6Steve]

The calibration of the sensor is dependant upon "emissitivity", esentially the absorption or reflectance of the surface. Flat black being the reference. Lighter/shinier the surface the more error. Better quality guns have an adjustment.

Google the term for more info than you ever wanted...

 

[mrvette]

What makes them so finicky ? Some days I'm really impressed with what you can do with them (like finding a dead cylinder by shooting the exhaust manifold) and then other days they just act stupid.
Short story...we bought an old park model trailer in Fl to use as our winter getaway (snowbirds) and I'm working on the roof. Got all the leaks fixed and moving on to different roof coatings for standing up to the Fl sun and reflectivity.
At the present time I've set up different surfaces and colors on the roof. Here is my situation. The roof is new roll roofing coated with silver dollar roof coat except for my test area's where I have left some roll roofing uncoated,some coated with black tar roof sealer and some coated with water based white elastomer coating.
temps.
black tar roof-- 160
uncoated roll---150
silver coated---125
white coated---125 ....???
If I put my hand on the black it will burn my hand,the silver is very hot but the white is almost cool in comparison.
Why ? Is the white "really" the same temp as the silver and for some reason doesn't transfer the heat to my hand ?

(Bottom line I want less heat coming through the roof into the ceiling of the trailer but with the heat gun I can't seem to see ceiling temp differences inside the trailer,but in reality the inside test is flawed because the diff colored areas are to small to make much difference.)

Yes, the colors make a difference, and on that roof, I am redoing a 40 y/o motor home with a fiberglass roof, patched with street sign aluminum in a few spots....p/owners has roofing tar on it, best to heat gun and scrape as much of it off there as you can, and wash rest off with gasoline...PIA mess I know....I going to paint it Rustoleum white gloss as with the rest of the thing, sometime soon enough...as the major mechanical work is done, and the paint is cheep and easy to apply.....

NOTHING reflects heat/sun loading like white, and white gloss is the best of that bunch....as it gets stained it gets painted again....

:bounce:

OH, and get that damn rolled roofing off there NOW, I put it on a roof addition here in Jax and it lasted about 3-4 years, got water under it for being shit material, and I dragged it out about 8 years worth with putting on 3 coats of cool white, finally gave the hell up and went to a metal roof a year ago....

rolled ASSfault roofing is crap....

 

[DWncchs]

Thanks guys. So white is the way to go and my hand is telling the truth.


Gene I know roll roofing is not very good but it cost me only $150 to roof it , I paid $300 for the trailer and its not moveable due to age, I don't own the land and the lease is $4200 and goes up each year (went up $200 this year), we hope to only be in it a few years until we buy something better, most old trailers in the park don't sell for much and most of the time get turned over to the park rather than pay the next years 6-6 lease.
The trailer 4 up from mine just had an aluminum roof over (as they call it)done for the crazy price of $5200. :amazed: Looks great and I'm sure will last and makes the trailer much cooler.

 

[010752]

To accurately measure the heat transfer, use the ir gun on the inside of the roof if possible.

The absolute best stuff to use is a product R500 made by
ALL WHITE MANUFACTURING, INC.
1507 SW 21st Ave
Fort Lauderdale, FL 33312
Call: 954 583-9178
Fax: 954 583-2475

Been using this stuff for years and you can tell the difference in temperature on the roof on a sunny day down here between it and the cheaper white elastomeric stuff that you can get at Homey Depot and Lowes etc.
This stuff is pricey but it works better than any other.

I have a flat roof on a house that developed a slow leak and dropped some sheetrock in the garage. I pressure cleaned, put some fabric on the bad spots and several coats of the cheapie stuff. After a hard rain, a few days later, got some bubbling in the rock again. Pressure cleaned again, put on a little better (more expensive stuff), several coats. Minor leaks again.
Found a 3 or 4 year old bucket of All White I didn't know I had, put a single coat on and after numerous rains, not a drop.
It annoys me about the price of this stuff, but obviously it is really worth it, besides being cooler than the competition.

What I am doing now is using the cheaper stuff to build up the mil layer and the All White to final coat.

Happiness is being on a hot roof in S Florida on a 95° summer's day in the scorching sun, completely drenched in sweat, so much that your leather boots are soaked, the sun goes behind some clouds and you get a chill.

 

[DWncchs]

To accurately measure the heat transfer, use the ir gun on the inside of the roof if possible.

The absolute best stuff to use is a product R500 made by
ALL WHITE MANUFACTURING, INC.
1507 SW 21st Ave
Fort Lauderdale, FL 33312
Call: 954 583-9178
Fax: 954 583-2475

Been using this stuff for years and you can tell the difference in temperature on the roof on a sunny day down here between it and the cheaper white elastomeric stuff that you can get at Homey Depot and Lowes etc.
This stuff is pricey but it works better than any other.

I have a flat roof on a house that developed a slow leak and dropped some sheetrock in the garage. I pressure cleaned, put some fabric on the bad spots and several coats of the cheapie stuff. After a hard rain, a few days later, got some bubbling in the rock again. Pressure cleaned again, put on a little better (more expensive stuff), several coats. Minor leaks again.
Found a 3 or 4 year old bucket of All White I didn't know I had, put a single coat on and after numerous rains, not a drop.
It annoys me about the price of this stuff, but obviously it is really worth it, besides being cooler than the competition.

What I am doing now is using the cheaper stuff to build up the mil layer and the All White to final coat.

Happiness is being on a hot roof in S Florida on a 95° summer's day in the scorching sun, completely drenched in sweat, so much that your leather boots are soaked, the sun goes behind some clouds and you get a chill.

Thanks for that info I will definitely check it out.
Have you ever heard of a product called Tropical 911 ,some of the contractors have told me they use it. Its around $115 for 5gal.
The company that sells it is ABC supply and they say they have others that go up as high as $350.:skeptic:

 

[68/70Vette]

The temperature of a sunliite surface is not necessarily a simple "black gets hot in sunlight" or "white is cooler in sunlight than black" kind of analysis. The color of a surface seen by the eye is due to light reflections in the visible part of the sunlight spectrum. It's not visible light that is determinative of heating, but rather infrared light (which the eye can't see). The heat of a sunlite surface is due to it's absorption of Infrared light. What is determinative of the amount of heating is the alpha/epsilon ratio (a/e). Alpha is the absorbtivity constant of a material surface and epsilon is the emissivity. Alpha and epsilon relate to absorbtivity and emissivity at infrared wavelengths. A surface with an a/e ratio that is a small number, or close to zero, will be cooler than a surface with a high a/e ratio.

Here's a good example to explain this.

Take two surfaces: one surface is highly polished aluminum and the other surface is a glass coated mirror. To the eye, a highly polished aluminum surface is highly reflective, and if polished sufficiently fine, will look optically very identical to the mirrored surface.

Now put them in strong sunlight for a while. The aluminum surface can be hot enough to burn your hand. The mirrored surface will be cool. Why the difference since they "look" almost the same? The reason is that for the mirror alpha (absorbance) is very small and emissivity is very large (at infrared wavelengths). For the polished aluminum, alpha is is large and emissivity is smaller than for the mirror. So a/e is very small number for the mirror and a much larger number for the polished aluminum. Hence for two visibly similar surfaces, one gets very hot and the other remains much cooler in sunlight.

(I think I've got this right, but it's been about 44 years since my graduate school days! )

 

[mrvette]

I go for the simple....stick my hand on it, white is the coolest color....

I have heard mucho theory on that, but to ME, it's a practical thing...

paint the roofs white in southern climates....

:clap:

 

[big_G]

I go for the simple....stick my hand on it, white is the coolest color....

I have heard mucho theory on that, but to ME, it's a practical thing...

paint the roofs white in southern climates....

:clap:

I like simple too. I knew white was cooler than black when I was 4 or 5...long before H.S. physics class....

 

[00fxd]

Heres one, Race engine shops always paint engine blocks black. To reflect heat. The engine is then always steaming hot when a white engine is cooler. It seems to me that black attracts and holds heat. What am I missing here?

 

[big_G]

Heres one, Race engine shops always paint engine blocks black. To reflect heat. The engine is then always steaming hot when a white engine is cooler. It seems to me that black attracts and holds heat. What am I missing here?

I believe black absorbs and radiates heat better than white.

 

[DWncchs]

I go for the simple....stick my hand on it, white is the coolest color....

I have heard mucho theory on that, but to ME, it's a practical thing...

paint the roofs white in southern climates....

:clap:

Simple is good but what I took from 68/70Vette's post is all whites are not equal.
I've done some reading about ALL WHITE MANUFACTURING, INC. and it looks as if their white absorbs less heat. Now to see if the different company'ss list the a/e ratio of their products.

 

[mrvette]

I go for the simple....stick my hand on it, white is the coolest color....

I have heard mucho theory on that, but to ME, it's a practical thing...

paint the roofs white in southern climates....

:clap:

Simple is good but what I took from 68/70Vette's post is all whites are not equal.
I've done some reading about ALL WHITE MANUFACTURING, INC. and it looks as if their white absorbs less heat. Now to see if the different company'ss list the a/e ratio of their products.

Be kind of curious as to what is what there, on a cost/benefit ANALysis....

I getting ready to paint the shingles this season....but need get a decent sprayer with a wide fan tip, I not staying up there all day on this shit....

doing the shingles on the old rolled roof, 400' worth, took me a couple hours with a roller and took 5 gallons per application....

I was up north in Maryland last weekend, and so noticed some very old farm house with metal roof....seams were about 16-20" apart, and then flattened down on the upper and lower ends....interesting....painted dark green, traditional color or the region.....then on the other out buildings I noticed the pattern change to the ~9" on center seams, looking like 3' wide steel cut the length, same as what's on my room addition now....

I never did learn what is meant by 'standing seam'.....and were the old roofs with that wide spacing soldered together or not??

I know my father got up on the ladder once with a HUGE old soldering iron and repaired some copper gutters, back when I was a little kid....

:crutches:

 

[010752]

I go for the simple....stick my hand on it, white is the coolest color....

I have heard mucho theory on that, but to ME, it's a practical thing...

paint the roofs white in southern climates....

:clap:

Simple is good but what I took from 68/70Vette's post is all whites are not equal.
I've done some reading about ALL WHITE MANUFACTURING, INC. and it looks as if their white absorbs less heat. Now to see if the different company'ss list the a/e ratio of their products.

If you go to FPL website (Florida Power and LIght) they have a section that lists all the roofing products and their specs approved by their energy saving program.

You don't have to try and reinvent the wheel, as MrVette said, use a high gloss white. The differences aren't that much, it translats into longevity in the harsh Florida sun. The more of the good resins used, the higher the cost. You can even use a good acrylic high gloss paint once you have the waterproofing part, cracks filled and mil thickness built up.

 

[010752]

I go for the simple....stick my hand on it, white is the coolest color....

I have heard mucho theory on that, but to ME, it's a practical thing...

paint the roofs white in southern climates....

:clap:

Simple is good but what I took from 68/70Vette's post is all whites are not equal.
I've done some reading about ALL WHITE MANUFACTURING, INC. and it looks as if their white absorbs less heat. Now to see if the different company'ss list the a/e ratio of their products.

Be kind of curious as to what is what there, on a cost/benefit ANALysis....

I getting ready to paint the shingles this season....but need get a decent sprayer with a wide fan tip, I not staying up there all day on this shit....

doing the shingles on the old rolled roof, 400' worth, took me a couple hours with a roller and took 5 gallons per application....

I was up north in Maryland last weekend, and so noticed some very old farm house with metal roof....seams were about 16-20" apart, and then flattened down on the upper and lower ends....interesting....painted dark green, traditional color or the region.....then on the other out buildings I noticed the pattern change to the ~9" on center seams, looking like 3' wide steel cut the length, same as what's on my room addition now....

I never did learn what is meant by 'standing seam'.....and were the old roofs with that wide spacing soldered together or not??

I know my father got up on the ladder once with a HUGE old soldering iron and repaired some copper gutters, back when I was a little kid....

:crutches:

The good, thick eleastomerics or rubber or whatever they want to call them will take a 3 to 4 grand paint sprayer to pump, the cheapies can't do it.

There are all kinds of metal roofing, the cheapest is the v groove, nailing on top of the v and overlapping the end vee. Next is the "r" panel, like most metal buildings have, 2 ft wide and edge overlapp with washered screws.

Standing seam is a "u" shape anywhere from 8" to 16" (depending on code approval) with the one side bent double over to cover the next upright on the "u". Bends are about an inch high. Then the joint is just crimped every 6" or so to lock, no soldering. No exposed fasteners to leak. The most popular these days. Great if done in white. Good costwise, if they will let you do it as a homeowner.
Made out of galv, alum, painted alum, galvalum, and that beatiful copper that ages blue-green, but too pricey for almost anyone. Copper gutters are still soldered and I believe in Orlando is the only manufacturer in the state.

Oldtime galv gutters were soldered too (helped my girlfriends dad in high school), but that left with those guys, use all seam caulks these days.