Soldering surprise at 0 gravity

science.nasa.gov...

Richard Grugel, a materials scientist at the Marshall Space Flight Center, watched his video monitor in disbelief. A transmission from the International Space Station was playing. The scene: Astronaut Mike Fincke touches the tip of a soldering iron to a wire wrapped with rosin-core solder.

Well, I'm not a space scientist, but what's so surprising about liquids forming globules and floating in weightlessness? Isn't playing with liquids in weightlessness the number one amusement for new astronauts showing off for the folks at home?

Did you watch the video Grady?

I'm thinking it may have had something to do with the solder chasing the heat around the wire, as it passed over each section it took some heat out, meaning the next section was hotter, and the solder kept moving towards the heat.

Probably something else entirely, just throwing this out there.

Whoops! Apparently, I didn't give the animation time to kick-in. Yeah that's the rosin doing a kind of orbit thing aroune the heated solder. Pretty cool.

Originally posted by Kano
Did you watch the video Grady?

I'm thinking it may have had something to do with the solder chasing the heat around the wire, as it passed over each section it took some heat out, meaning the next section was hotter, and the solder kept moving towards the heat.

Probably something else entirely, just throwing this out there.

SOLDER ALWAYS TRIES TO FLOW TO THE HEAT, BUT GRAVITY STOPS IT. This should have been predicted, and NOT a surprise.

It was still Cool ! umm hot lolol

Originally posted by groingrinder

Originally posted by Kano
Did you watch the video Grady?

I'm thinking it may have had something to do with the solder chasing the heat around the wire, as it passed over each section it took some heat out, meaning the next section was hotter, and the solder kept moving towards the heat.

Probably something else entirely, just throwing this out there.

SOLDER ALWAYS TRIES TO FLOW TO THE HEAT, BUT GRAVITY STOPS IT. This should have been predicted, and NOT a surprise.

The solder was stationary after it melted.. The rosin is what was moving.

I would have been really surprised if anyone predicted this, I've done a lot of soldering and the rosin usually doesn't move at all.

Seems reasonable enough to me to think that the rosin is simply 'chasing' the heat, as Kano suggested... but it sure looks cool, doesn't it?

I wonder, though... could the soldering job be completed? And, if not, what kind of solution are we looking at here?

Originally posted by Odd
I wonder, though... could the soldering job be completed? And, if not, what kind of solution are we looking at here?

Yes, if you read the article they only debate about whether rosin pockets will remain in the solder. The rosin is only there to prevent oxidation, so whatever weird thing it does is irrelevant as long as it evaporates or leaves the solder blob.

Doesnt seem all that important to me.

there is a picture somewhere of what fire looks like when it burns at zero grav and it burns in a perfect sphere (provided there is oxygen)

It would theoretically have to burn in a perfect sphere. Because there's no gravity to deform the gravity, the source of heat would burn out in all directions equally, hence, a sphere.

Basically the same reason water droplets float around in spheres.

If it would "chase" the heat wouldn't the heat need to be non centered and the majority of rosin be some where away from the heat? If the heat and solder and rosin are all even then maybe thats why the earth spins around and circles the sun? Its sort of like how water swirls as it goes down the drain with gravity.

Maybe its like the bearing motor?
homepage.ntlworld.com... .

I like the thought about the relationship of this image to the mechanisms of the solar system, where the Sun represents the hot solder ball and the earth or the planets represent the liquid rosin in orbit about it.