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.
> 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.
> 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.
So my obvious solution is obviously too obvious to be right, and obviously the right solution is not obvious.
The sad thing, is you are just reiterating what I've said already, without providing any useful answer. "Paint obviously is not the right tool" is a statement that not just not obvious for me, it looks simply wrong. They search for microcracks and use a sealant to seal them. Sealant is not a paint obviously, but in the same ballpark.
The sealant has to be self-setting; it cannot rely on atmosphere to "dry" it, because the side facing the hole will never dry. In order for it to dry, it would have to be air-permeable, so not a good sealant at all.
So, the sealant has to be either a 2-part epoxy (harder to mix and apply), or a UV-cured epoxy. It has to adhere to a vast array of surfaces, since we cannot predict if the next leak will be in aluminum, cracked ceramic, silicone gasket, rubber gasket, plastic.... Anything it outgasses must be extremely inert, so that it doesn't cause a new problem when it reacts with a different surface (the gas on the ISS is never diluted by a giant planetwide reservoir).
Paint is obviously not a two-part epoxy nor a UV-curing epoxy; nor is it guaranteed to have fully inert outgases; finally it is not likely to be adherent to all the possible surfaces.
It's as if the situation requires a robotic diamond drill, and you propose we hit it with a big rock. The big rock won't do.
In general, gaffer's tape is the superior product, but for this use case, I'm thinking that duct tape with its solid backed film and thicker adhesive might be more airtight.