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'Whitest ever' paint reflects 98% of sunlight

bbc.com

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Re: 'Whitest ever' paint reflects 98% of sunlight

#151

Post by macspoofing »

cyberlab wrote: post #4

Someone needs to compile a list of all this fringe tech that I see popping up in my feeds, almost daily now. I know there are techpress blogs that pump out articles like this, but there doesn't seem to be an authoritative compendium of such tech anywhere on the net. I could curate this by hand with 3 hours of free time and some Red Bull I suppose. The reason I want this is because we seem to be swimming in innovation…

>The reason I want this is because we seem to be swimming in innovation, but nobody to aggregate and make sense of it all, and `join-the-dots` of all this tech so we can make even bigger leaps with it.

There is. It's called "the market". Each one of those innovative ideas gets tested by their inventors and backers against real world use-cases. Nothing validates an idea or innovation more than someone writing a check to buy it.

Re: 'Whitest ever' paint reflects 98% of sunlight

#152

Post by neurostimulant »

dheera wrote: post #130
dejj wrote: post #2

Also: Black 3.0, the purchasable variant of Vantablack For sale at: https://www.culturehustleusa.com/

I tried it. It's not that black at all. My regular black T-shirt was blacker than a piece of cardboard I painted with Black 3.0. Super disappointing, to say the least.

Maybe it was applied wrong? The website mentioned that porous materials must be sealed first before spraying with black 3.0.

Re: 'Whitest ever' paint reflects 98% of sunlight

#153

Post by FredPret »

earthscienceman wrote: post #128
jeffbee wrote: post #123

Earlier quoted context omitted.

Wouldn't the reflectivity degrade almost immediately, as dust landed on said painted surface?

Geo-engineering is an extremely flawed way to approach the climate change problem, for a million reasons including this one.

The Nazi’s had an idea of launching a sun gun (Sonnengewehr) made of sodium metal I think. It would then fry the Allies with focused sunbeams. They were also on meth by the way.

However maybe we could build a bunch of similar mirrors in the Earth-Sun L1 Lagrange point (reflecting light straight back at the Sun of course!)

Re: 'Whitest ever' paint reflects 98% of sunlight

#154

Post by clairity »

mauvehaus wrote: post #150
clairity wrote: post #129

Earlier quoted context omitted.

one thing i’ve learned from doing little home improvement projects over the past few years is that paint is a 2-part product, primer and topcoat, and neither should be skipped if you want good results. generally speaking, primer sticks and seals while topcoat colors and protects. this isn’t made obvious in any way to the novice, and big box store workers seem as ignorant about it as anyone.

Depending on the application, the primer coats can fulfill a couple other requirements as well: If you want a really smooth topcoat, you usually want to sand past what you can reasonably/economically/effectively do on the substrate. Some primers are formulated to sand nicely to a powder (as opposed to balling up in clumps on the paper). You'll see this spraying higher quality paint grade work. You have to have a dece…

> “If you're finishing pine with knots in it, you'll want a primer that will seal the knots, otherwise the pitch will eventually bleed through and discolor the topcoat. Shellac excels at this.”

yes, i learned this the hard way, albeit on a simple set of wall shelves as cat stairs that i can easily fix eventually with shellac and another topcoat (when i get around to it).

Re: 'Whitest ever' paint reflects 98% of sunlight

#155

Post by the8472 »

If the goal is to keep buildings cool you don't want your paint to be as reflective as possible in the whole solar spectrum. You want it to have a low reflectivity (thus high absorption/emissivity) in the infrared window[0] where you'll emit more into space than you'll absorb and high reflectivity in the rest of the spectrum.

[0] https://en.wikipedia.org/wiki/Infrared_window

Re: 'Whitest ever' paint reflects 98% of sunlight

#156

Post by com2kid »

the8472 wrote: post #155

If the goal is to keep buildings cool you don't want your paint to be as reflective as possible in the whole solar spectrum. You want it to have a low reflectivity (thus high absorption/emissivity) in the infrared window[0] where you'll emit more into space than you'll absorb and high reflectivity in the rest of the spectrum. [0] https://en.wikipedia.org/wiki/Infrared_window

Better article over at https://phys.org/news/2021-04-whitest-hereand-coolest-litera... says that lots of energy saving paints already reflect tons of IR, a large portion of their (incremental!) improvement over previous paints in this area is specifically because they expanded the range of wavelengths that are reflected.

Re: 'Whitest ever' paint reflects 98% of sunlight

#157

Post by everybodyknows »

rtkwe wrote: post #21
SamBam wrote: post #11

I assume this could be useful to shield something in space with extremely specific temperature tolerances. I'm not sure about the suggestion that people are going to paint their roofs with it. People already have the opportunity to paint their roofs with cheap white paint which would provide nearly all the benefits this would, and still choose not to do it.

White roofs don’t look great which is why I think they’re largely relegated to commercial buildings instead of residential ones. They get dirty fast, are super bright and don’t fit with the traditional look for houses. On commercial flat top roofs they are hidden so it doesn’t matter if they’re blindingly bright or stained because they’re not visible.

I'm recalling a technology from 70s Southern California: low-slope, tar paper for water seal, half-centimeter fragments of broken light-colored rock scattered on top. Dust falls through the gaps onto the tarpaper.

One downside being that after a heavy rain, some fraction of the gravel makes its way down from the roof.

Re: 'Whitest ever' paint reflects 98% of sunlight

#159

Post by Applejinx »

dheera wrote: post #130
dejj wrote: post #2

Also: Black 3.0, the purchasable variant of Vantablack For sale at: https://www.culturehustleusa.com/

I tried it. It's not that black at all. My regular black T-shirt was blacker than a piece of cardboard I painted with Black 3.0. Super disappointing, to say the least.

Your T-shirt's a 3d structure with microfibers. I'm not surprised it was able to be more black than a hard surface: fabric's actually a really good way to make an intense black.

The Culture Hustle blacks are also matte, which is very much a limiting factor (and part of the concept). I find if you're willing to accept highlights, super gloss black is way better at being super black everywhere that isn't a highlight. At that point you're trying to get the most localized highlight as possible, to get it out of the way so everywhere else can look blacker.

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