Cold Welding Metals In a Vacuum

At 7:20 I definitely did not mean Celsius I meant Fahrenheit, lol. I don’t think I’d be very comfortable in a 60 degree Celsius lab.

Great video! Two questions: 1) For the vacuum chamber test, wouldn’t you need to remove the oxide layer that is already present on the surface of the two metal pieces? Just putting them in vacuum does not remove the oxide that is already there 2) Would an inert atmosphere (nitrogen?) work instead of a vacuum?

Given the melting point of gallium is under 30° C, the slightest friction may cause spot welding.

I asked for this is the comments ages ago, never thought he’d get round to do it! Great video as always.

So when I push these two pieces of aluminium together, they should stick together. But they don't. (Vsauce music).

The fact that it didn't work the first time shows us how genuine your channel is.

but... removing the air doesn’t magically make the oxide layer disappear? it only would keep it from forming after forging

I'm skeptical about whether you were able to actually cold weld. My understanding is that for cold welding to be successful, you have to get the surfaces scrupulously clean. I wonder if what happened was that a vacuum was created between the two pieces of metal and the edges were so well sealed that air could not get in. You probably had about 1.5 sq-in of surface area there, which would mean around 21 lbs of air pressure. When you take new microscope slides out of the package, they will stick together because they are so flat that the air cannot get between them. (Idea for an episode?) High karat weight gold should be easy to cold weld because it has no oxide layer. Would it work to put a sheet of gold leaf between two very flat silver ingots?

This is so cool! I have an oral presentation to do at the end of my year and your channel is a gold mine of intersting science phenomenons. Thank you for the inspiration! Love your vids

Tis is also the reason why in slow moving mechanics like in clocks where you can't reliably get an oil film in between moving gears then instead you make the gears out of different materials. It's not because brass is cheap as some people might think. It's because the alloy brass (copper and zinc) won't cold weld with steel (iron). The result is that you get a clock that lasts for generations. Had all gears been made out of the much stronger steel it wouldn't last as long as the steel would grind away because of cold welding. Naturally the largest gears are made out of the softest material as that causes gears to wear more evenly.

Galling is one of the reasons we don't typically use stainless steel anchors for pool safety covers. They are made from brass since they resist galling and oxidize to a nice dark finish that compliments most deckings.

You have the least click baity titles.. I usually have to force myself to watch your videos because whenever I do watch your videos I'm never disappointed.

man i was so sccared about your fingers getting stuck inbetween the 2 monster magnets

I like these videos a bit more than the ultra black paint kind. Keep it up!

7:17 Shouldn't it be Fahrenheit? Galium melts at 29,76 °C

James, your genuine excitement over the things you discover in your videos is infectious. Thanks for the killer content!

I am from indian and my name is ojas and i am of 13 years but has interest in science and i always see this man all videos how he explains that is the best thing of him he explains very clearly

I worked in Q.A. in manufacturing for years. We used to "wring" gauge blocks together. The phenomena is not entirely understood, but "cold welding" is thought to be in play. Galling: We press fit steel parts together and with certain product designs we'd get galling, and it took a lot of small process changes to eliminate it.

The attraction between the large neodymium magnet and the even larger magnet neodynium magnet through the glass was like a desperate boy wanting to meet his crush Lol

You need some sort of acid (perhaps ammonia) to first etch away the oxide layer while inside the vacuum, then stick them together. to really get the ingots to fuse.