Henry's Tropicool, and how I learned to dislike it...

[musigenesis]

Originally Posted by PitskyWitbulls

Literally meets your requirement for comparison, dismissed as placebo effect. That's enough internet for me tonight.

Well, those were my requirements, EastCoastCB said placebo effect. TBF I might also have said something like that eventually, but I think it's reasonable to want a more controlled testing process than "I did this and it felt cooler", especially when thermometers are easy to come by. Perhaps this is an unfair representation of what Dr. McBusFace actually did, so I'll check out the video if I can find it.

[Mountain Gnome]

Originally Posted by ol trunt

Just as an aside, smooth, shiny white surfaces reflect better than rough, dull white surfaces.
Jack

Which is why I painted my roof with gloss white enamel paint. It was supposed to be clear and warm. Clouds moved in immediately, and due settled. Then it froze. For all 4 coats. So now I have a rough dull white roof.


I added "Insuladd" ("makes paint insulate") to the first 2 coats, as recommended by ... oh shoot, there goes the brain again...I can never remember names, but the amazing old "hippie" gent from TX with the amazing bus he was building from scratch who unfortunately moved on to the next dimension.


Anyway, the stuff says it was invented by NASA and is little ceramic balls. It left the paint like sandpaper, so it took another two coats to get it smooth. But then it froze again anyway.

[Native]

You are thinking of Tango!

[Native]

Oh, here is a link to the pseudo-science that a member, Jatzy, performed on various products.

[leadsled01]

Last weekend I coated 3 coats of hernrys tropicool 100 % silicone on my enclosed trailer and we are in a heat wave all week. Very noticeable cooler inside trailer every time I open the door compared to week before when temps were slightly cooler.

[ol trunt]

Yup, white will do that every time
Jack

[jazty]

Originally Posted by ol trunt

Yup, white will do that every time
Jack

Exactly.


Paint doesn't insulate worth anything useful. Period. It's too thin.


The colour of the paint does, however, affect how much radiant energy is absorbed or reflected.


Pure black paint absorbs 100% and reflects 0% of visible light radiation and thus gets quite hot.
Pure white paint absorbs 0% and reflects 100% of visible light radiation and thus can stay the same temperature as it's environment (not cooler).


Living in an imperfect world we don't get pure white or pure black, but something in between.

[jazty]

Texture and glossiness also plays into the heat absorption.

[PitskyWitbulls]

Originally Posted by musigenesis

Well, those were my requirements, EastCoastCB said placebo effect. TBF I might also have said something like that eventually, but I think it's reasonable to want a more controlled testing process than "I did this and it felt cooler", especially when thermometers are easy to come by. Perhaps this is an unfair representation of what Dr. McBusFace actually did, so I'll check out the video if I can find it.

I linked two articles that show there is a difference between just white paint and roof coatings. White paint alone will not lower roof surface temperatures by 87(F). Standard acrylic paint changes the color of your roof. That’s it.

[Mountain Gnome]

Originally Posted by PitskyWitbulls

I linked two articles that show there is a difference between just white paint and roof coatings. White paint alone will not lower roof surface temperatures by 87(F). Standard acrylic paint changes the color of your roof. That’s it.

Wait...what did I miss....


WHAT will lower the roof surface temp by 87°F? (besides a block of dry ice)



Or does 87(F) mean something else?

[jazty]

87F on it's own doesn't mean anything. The best you can theoretically ever hope to achieve with a roof coating is to get the roof down to ambient temperature.

[jazty]

If you want to get below ambient temperature you better get on the roof with a hose

[PitskyWitbulls]

Originally Posted by Mountain Gnome

Wait...what did I miss....


WHAT will lower the roof surface temp by 87°F? (besides a block of dry ice)



Or does 87(F) mean something else?

there are two articles linked in this thread. Both talk about roof coating as opposed to paint.

[EastCoastCB]

Originally Posted by PitskyWitbulls

White paint alone isn't as thick and it doesn't contain any special reflective components. RV roof coats are thicker and contain reflective additives.

I understand the studies linked are on buildings not a school bus but an 87F drop is still significant.

https://www.bbc.com/news/world-48395221
https://heatisland.lbl.gov/coolscience/cool-roofs

Neither of those address using silicone-rubberized paint on a vehicle. Neither address why the OP and many of us don't want elastomeric roof coatings on our buses. Obviously you're free to use it and free to tell others how great you think it is.

and the bbc article you linked is specifically about white paints/coatings in general.

[PitskyWitbulls]

Originally Posted by EastCoastCB

Neither of those address using silicone-rubberized paint on a vehicle. Neither address why the OP and many of us don't want elastomeric roof coatings on our buses. Obviously you're free to use it and free to tell others how great you think it is.

and the bbc article you linked is specifically about white paints/coatings in general.

I never said anything about it being used on buses and explicitly said they are on buildings, not bus roofs. I never said either article was about using rubberized coatings on a school bus. However a little extrapolation will get you to where I was going.

The BBC article states they used limestone in the coating to increase reflectivity and it did reduce the internal temperature. The other article where they did test the rooftop temps before and after coating with thermometers (on a steel building not a school bus) the surface temperature did drop significantly.If even a fraction of 87°F translates to a bus roof, it will make a difference.

In the south where the sun is oppressive, every little bit helps. My entire bus is white. It's also insulated with a ship-lap ceiling. I've done everything I can inside to reduce the heat. Awnings are the next solution but that is a $2000+ investment.

$114 and a sweaty afternoon sounds a little better than a $2000 hit. Obviously you're free not to use it and insist to others it doesn't work but isn't that like someone without a tattoo telling you how much they hurt?

[EastCoastCB]

All I'm saying is if you end up hating it like the OP and others its a LOT of work to remove and paint properly.

[PitskyWitbulls]

Originally Posted by EastCoastCB

All I'm saying is if you end up hating it like the OP and others its a LOT of work to remove and paint properly.

I'm gonna stick with the tattoo analogy.

[EastCoastCB]

Its not a good one at all. They do hurt. I have plenty.

[BartStephens]

I understand the studies linked are on buildings not a school bus but an 87F drop is still significant.

https://www.bbc.com/news/world-48395221
https://heatisland.lbl.gov/coolscience/cool-roofs[/QUOTE]


Excellent resources. Thank you for sharing.

[BartStephens]

Wow. I am reading myself bananas on this subject. I am going to do a comparison test.

QUESTION:
Setting aside elastomeric,...just PLAIN WHITE PAINT,...do any of you have a recommendation? Brand? Type?