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For every complex, difficult and hard problem, there is a simple, easy and wrong solution.

Paint obviously is not the right tool for making seals air tight.

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You ever try to open an old paint can? Checkmate, atheist.
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It is not obvious to me that there is no specialized type of paint that would be appropriate.

Doing the whole module sounds like a lot of mass though.

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It's hard vacuum on one side. There's a reason the word "hard" is used to describe it.

A few years ago a Soyuz was improperly drilled during manufacture. This was patched with a super epoxy... and then began leaking air on orbit. Paint won't seal what a super aerospace epoxy failed to seal.

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> There's a reason the word "hard" is used to describe it.

Because it's more extreme.

Do you think a soft vacuum of 0.002 atmospheres of pressure would be notably easier to prevent leaks into?

> A few years ago a Soyuz was improperly drilled during manufacture. This was patched with a super epoxy... and then began leaking air on orbit. Paint won't seal what a super aerospace epoxy failed to seal.

Wasn't the fix on the ground a secret patch by the person that drilled the hole? I don't trust that to have been done properly.

And then when they noticed it was leaking... they used the super aerospace epoxy. Which was labeled as temporary but as far as I know it's still the fix.

Also that was a serious hole, 2mm wide, not a microhole like you'd try to fix with paint.

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Flexseal obviously
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You're being sarcastic, but I would like a technical explanation of why this would not work.
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Delta P
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Delta P is one atmosphere or less, like 15 PSI. Lots of stuff can handle 15 PSI.

Now, will it immediately off-gas and embrittle on exposure to vacuum? Different question.

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How about _Space_ Flexseal?
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How about glue?
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Bubble gum? Like do they chew space bubble gum that they could then smoosh in the holes?

In college, we'd use toothpaste for the holes left from nails in the walls we hung up our posters with.

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Don’t try this if your toothpaste is the blue or green minty flavoured type. You’re welcome.
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We actually did this in my freshman dorm room, as the paint color almost exactly matched the original Crest "green".
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Isn't the main problem finding the hole and not what should be used to fill the hole?
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Just spray Fix-a-Flat everywhere.

Or coat the outside with a soapy water solution.

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They're not teenage boys.
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You'd think after 8 years, they'd have found the hole!
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They need Matt Damon, a chopped up wooden crucifix, and some silicone caulking
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They need Phil Swift, "To show the powerful adhesion of flex-seal, I sawed this space station in half!"
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It's time to kick ass and chew bubble gum... and I'm all outta gum
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Duct Tape, the answer is always duct tape
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Found the scrub who doesn’t know about gaff tape
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They did use space tape (Kapton) and epoxy for that weird case with the hole drilled in the ISS.
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can't one of them just put his thumb in the hole? duhhh
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If you mean on the outside, paints that apply well in vacuum and microgravity probably need to be developed and tested first.

If you mean on the inside, it'd be a lot of time and disruption to devote to maintenance on a station that's already having to spend an increasing amount of time on maintenance instead of science.

The modules have a lot of stuff that has been wired between them over the years, all that would need to be sorted out, consequences understood and more before ever starting the work, and by then it'll be time for the ISS to retire anyway.

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> well in vacuum and microgravity probably

Wouldn't all paint works well in microgravity? If it didn't, I would think you wouldn't be able to apply it to your floor, walls, and ceiling, with the same paint.

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I think it's hard to say. Water sprayed at a ceiling doesn't congeal into a ball the way water floating in microgravity does.

Paint that would fall to the ground if it didn't stick to anything on Earth, would just be floating around in microgravity. Any dissolved gasses or moisture can usually passively sort themselves out due to their differing masses, but again, not in microgravity.

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Yeah, the application system is probably the tricky bit, rather than the paint.

> Any dissolved gasses or moisture can usually passively sort themselves out due to their differing masses, but again, not in microgravity.

This is a solved problem with the ECLSS system [1], required from humans releasing ~3.3 lbs of water per day, and exhaling gases that must not accumulate or form dead zones, and normal VOCs scrubbers [2] due to most modern materials releasing them.

I suspect it would be more of a "how many extra filters do we send" type problem and cycling the collected water a couple more times.

[1] https://www.sciencedirect.com/science/article/abs/pii/S13640...

[2] https://www.researchgate.net/figure/Typical-concentrations-o...

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Not OP but I’d imagine the big problem with microgravity is not after application but during application. No idea the scale of that problem but obviously open cans of liquid paint are not realistic (not that anyone was suggesting they were)
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Some problems i can see with that:

It might be hard to access the actual pressure hull from the inside (there's probably insulation and padding on top)

If you use paint, you somehow have to get rid of the solvent in it when it dries, which might be a problem when painting a whole module

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Air filtration is one of the hardest things do deal with in space.

I don't know what solvents would do, but I remember that astronauts' bone density loss in space means there are challenges around managing the significant amount of calcium captured by the air scrubbers in the ISS.

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Wouldn't the calcium go out in your urine?
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Do they literally sweat their bones away? I can imagine how it would work on molecular level via sweat / breathing, but I would expect >99% to be simply pissed and shat away.
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yeah, why can't they just make astronauts wear goggles, then stop the fans, and tell them to squirt some superglue in the air to let it clog the hole?
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Put a bit of spare sheet metal over the hole and let the pressure differential hold it down. For added safety affix a post-it not with DO NOT REMOVE written on it in all capital letters and underlined. They can even use those special zero-g ballpoint pens they spent eleventy-billion dollars inventing back during the johnson administration.
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Oh come on you can't be serious.

Clearly this needs some JB-Weld :P

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Flex Seal would be my suggestion. It works as seen on TV
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"To show the powerful adhesion of flex-seal, I sawed this space station in half!"
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> But I wonder why it is impossible to do.

Because, space. It's hard. Unbelievably hard.

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Some fire decal while they're at it?
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Cardboard's out. No cardboard derivatives.

Paper?

No Paper. No string. No sellotape.

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