Cold Welding In Vacuum 

Thanks for testing so thoroughly! Very interesting to see how difficult it is to get a cold welding result!

Cody: Cold welding is all about cleanliness and flatness. Speaking from experience, physicists doing high-precision experiments don't have to worry about cold welding effects until they are utilizing ultra-high vacuum (UHV) systems. At those pressures, nothing is generally able to be dirty (because it if were, then the pressure would be lower anyway, because even metal outgasses to some degree). Think of it this way. Metals are really just atomic lattices. If you zoom in so far as to be able to see the atoms (at atomic resolution), then in the absence of anything else (oxide, dirt, crap, whatever), you'd just see an incomplete lattice (probably rebonded at the boundary) and then nothing else (just vacuum). If you have two such objects and then touch them together, then you literally have just one complete object. In other words, cold welding is the effect of making two objects one, quite literally. If you zoomed into your samples (which you probably think are relatively clean already), you'd be shocked to see how much gunk there is on them in the form of water vapor and other stuff on the atomic scale, even with the oxide completely removed. Moreover, you have to have very flat surfaces in order to cold weld properly. Polishing to a tiny grain size is almost a must in order to see the effect. The problem comes in because there's almost always just way too much junk in the way in order to actually cold weld something. Oxide will obviously be in the way, but even if you remove all of that, there's still a lot of stuff that will cause problems. If you have an UHV vacuum chamber and clean it with chemical solvents for days and bake the hell out of it, you're still going to be pumping for quite a while before you reach UHV pressures (circa 10^-10 to 10^-11 torr). Scientists who use UHV will tell you how arduous it is to get their chambers down to UHV pressures. Even a single fingerprint accidentally left on the inside of a UHV chamber will cause the pressure to be high for months. For this reason, everything that goes into the system has to be ultra-clean. Parts have to be cleaned with chemical solvents over and over again (often using an ultrasonicator) and so forth. The chamber itself has to be baked for a long time to remove the excess fluid pressure of the moisture left inside. Conflat flanges using copper gaskets have to be used in lieu of traditional o-ring seals because at those pressures traditional seals will fail. You absolutely cannot touch anything which goes into a UHV system with oily (ungloved) fingers. In short, UHV is a lot harder than normal vacuum pump work. And yet, you really need UHV pressures in order to see proper cold welding. Sure, you can twist parts together at atmospheric pressure, but you're really just lodging the metals together in certain places and causing them to hook together because they are not atomically flat in places. You're just using the non-uniformity of the (presumed flat) samples that you have in order to simulate a cold weld. True cold welds should be permanent, because it's really just touching one half of an exposed, polished, flat metallic surface to another, making one piece. I hope that makes sense. In summary, once again, cold welding is all about cleanliness and flatness. Thankfully, it is much harder to achieve than it is, because otherwise us scientists would have a devil of a time trying to get anything done!

"So I've set up a mouse trap here and fixed the two pieces of gold to it" I love you, Cody.

Cody, Another approach you could try is to freeze one piece of gold in the liquid nitrogen so that it shrinks, next clamp it together with the other piece of gold, then as the frozen piece starts to warm up it will expand and possibly lock the two together. anyway great video!

Cody, can I just say, I have so much respect for you still posting videos of "failures" like this, where you didn't obtain the desired result. It brings the viewer along with you on the journey of discovery and shows the process of trial and error that is necessary to learn anything. I notice you often have a bunch of know-it-alls in the comments going "oh well OBVIOUSLY" and "I can't believe THAT didn't occur to him", as though it's possible to know everything or that they always knew the things they know. You are obviously quite smart and knowledgeable on a wide range of subjects, and I really appreciate that you don't pretend you magically just knew everything from birth.

Have you degreased the gold? Probably there was a thin film of oil or other organic stuff that prevented cold welding. Try a piranha solution or a concetrated solution of sodium hydroxide in ethanol. They are powerful degreasers especially the piranha solution. Also you can check if water beads up on the surface which would indicate that surface isn't clean enough.

4:45 am i going crazy or do i hear two different things being said?

Cody's so close to 1,000,000, help him get there 😀

can you extract calcium from bones? I'm the same guy as last video

was that an editing error 4:46

1:53 So here's what I came up with... LET ME SHOW YOU ITS FEATURES!

This is seriously one of the coolest interdisciplinary videos I've seen. I've watched most of these videos over the past year or so, and for whatever reason this particular video really stood out to me. Please do more like this. For what is's worth, I agree with the logic behind grinding the metals together vs. slamming them together. If cold welding can only take place if the crystals from the different halves are aligned in some specific way, it would make sense that rotating the two surfaces in opposite directions would be particularly effective in providing more opportunities for this to occur.

when will you be continuing rocket videos? is it because of the lack of a licence?

When I tig weld aluminum, after I'm done "molten puddle is solid" during the post flow of gas I can stick my filler rod to the piece near the weld and it sticks together. When you weld aluminum it burns the oxide layer off and is under 100% argon gas (inert) this could be a great way to verify your oxide layer and oxygen molecules sticking to the surface theory.

4:47 Lol we now have 2 Codys arguing

I appreciate your channel because you're not just blowing shit up for fun and calling it science. You actually explain what is going on and use the scientific method to answer real questions.

Rockin' the chamber! yes, love that band.

You worry about a single layer of O2 atoms on the gold, but not worry about a 'mountain' of molecules of grease from your hands on that gold? No wonder it is not cold welding. Besides those gold bars were not polished enough - they have to be mirror polished.

Searched for this video after seeing your comment on AvE’s channel. Glad you delivered!

Good stuff Cody!! As always....Ave was the channel that brought me to your channel!! Great couple of minds

next video Cody goes to NASA and cold welds in space

Guys this guy is a genius !

awesome that you two are figuring shit out together. blowing my mind that my 2 favorite youtubers are doing collabs. keep it up guys!

i've been subscribed to AvE and you for a while and happy to see great minds coming/working together

When you wring the gold and indium together and they 'weld' could that just be that two soft metals deform under the pressure and gall up and they aren't welded? Is there a fusion line when you do this?

Dear Cody- Think of how much cooler your life would be if your last name was Slab. Thanks

My day is made. I just saw a collaboration of my two most favourite RU-vidrs'. So much love!!!

Ahhh so close to 1 mil! Your videos are genuine, and I love watching them. Should have been at a mil long time ago!

Did you take into account the temperature of the metals? Maybe twisting the bars together heats and energizes the atoms a little and allows it to happen. Why don't you try heating the bars and then touching them together. not hot enough to melt but just to like 200 degrees. Another possibility is while twisting the bars together obviously doesn't increase the temperature of the bars themselves to melting temperatures. But maybe the surface atoms for a brief moment get heated up to their melting point. But this heat can't be measured because its only a couple atoms that are that hot for a fraction of a second. Maybe the surface atoms of the bars are several thousand degrees for the moment you twist them together and that causes them to melt together.

Cody, what if it was the WAY energy is introduced? When you rub them together the energy is spread rather evenly throughout all crystalline planes, while when striking you make point contact, being the number of planes interlocking or joining (welding) smaller and cannot hold back the rebounce (after all it is an ellastic material). Just like the force of rebounce exceeds that of the weld and it breaks off instantly?

I love your glasswork, great idea on removing the chance of a contamination by mercury. That Sprengel pumb is just pure awesome. Keep up the awesome work.

Really well done man!! Like how you kept trying different things and pursuing a real result. Thank you for the great vid!!

i was gonna make a joke about sodium, but Na

I've always wondered if the 'bouncing back' from smashing the metals together breaks/prohibits the cold welding. like the plates should wobble around at least a little bit from the force of the impact, which i can imagine, is counterproductive for the welding... also: cool poster, DFTBA ! edit: have you ever tried just pressing the two together in a vacuum? It's probably way harder to do, but that would definitely eliminate that theory.

Thank you so much for your regular updates. I make a point to watch every video and to like them also!

You, ave and the essential craftsman are my favorite RU-vidrs! Keep up the videos and thank you for all the interesting knowledge.

Sounds interesting. Will be interesting. Let´s take a look. Good to have no plans for the next 20 minutes...

Cody, i have a good question. Will a polaroid picture develop in a vacuum? Please answer this I've always been wondering, and since you have a vacuum, i was hoping that you could find out.

I love how my two favourite channels have been collaborating

Dude that's so cool you're working with Ave. you guys make an interesting friendship. Excited to see more. He's a fun Canadian guy, knows everything about tools.

Cody ! I'll keep spamming my question then :P Why won't the oxidized layers on two material cold weld, they are basically the same material does cold welding happen only for pure elements and not compounds ? why?

If u can u chould do more mining videos

Great video as always, Cody! I've been looking forward to this one for a bit.

Cody you came a long way. I remember 2 years ago when I subscribe back with the green house water plants and solar panels in about. Now you have 1 mill subscribers. I love this channel for it's scientific research and test.

My cannabis seeds just came in this morning! I'm so stoked to get this season going!

try putting a natural sponge that is holding water inside a vacuum

You make a good case for explaining asteroid accretion in the vacuum of space. With the static electrical potential you mentioned in the radiometer video, and eventual gravitation effects, space dust-to-asteroids becomes a pretty straightforward process.

This is the best science video of 2017 for now. The bar is set pretty high now. 😀

MAin problems, in my POV: Low vaccum (you must go to high vaccum to notice any difference). The ones with turbo or diffusion pumps. Your mechanical vacuum should be around 1 or 0,1 Torr, which is still a lot of air. You should go to at least 10-6 Torr to get sth. Second, surface roughness, you should go to extreme polished, lapped surfaces with nanometric roughness. This might be tricky without specialized equipment.

Can you make a PhD out of this though?

Dig it. I've been an avid watcher yourself and AvE for a long time. I was pleased to see you chime in on one of the vidjehos in his chat channel. It's a good combination in fact and hopefully more collaboration is possible. Fans of both will dig.

'Him and I get along pretty well' I would too if someone sent me gold bars :) AvE and Cody's lab are the two Chanel's I look forward to watching all the time.

its it Ave or A-V-E (just how you say the channel)

4:45 lol

Love this channel. It's like lab everyday. If you want to it'd be awesome to have a second channel with calculations for the experiments that can be explained that way. AWESOME Job

I love how my two favorite channels on youtube just so happen to work with each other.

can you do more on you hydrogen generator please

4:45 Cody turns into a demon

What amazes me most is the fact that cody just comes up with these genius contraptions to interact with objects inside the chamber. :D

2:40 Wow, this is quite the cool rig, love what you come up with Cody!

Gold is so unreactive, it doesn't even like itself.

4:46 editing fail

Love your channel, would haven't seen it but for that scoocum chocher AvE.... One love my brothers, please keep making me smarter!

Cody vibrating the metals to get them to weld reminds me of a process used to weld copper in atmosphere. It is "ultrasonic welding" process that use high frequency vibration and pressure are used to weld the materials. Looks similar to what you did in vacuum but it need much more energy to weld in atmosphere.

My understanding of the process is that both metal surfaces have to be exposed once in the vacuum to prevent any oxidation layers forming, to achieve this you could use the same basic rig with magnets but replace the falling weight with a cordless drill and the cleaning cloth with an abrasive such as Emory cloth. Once at vacuum a length of the emory cloth gets spooled by the drill removing any contaminants and hopefully giving the clean surfaces needed. Another point I'm sure other people have mentioned is grease contamination from your fingers, wiping the surfaces down with a degreaser such as alcohol and then handling the pieces with either surgical gloves or tweasers might help. Anyway, thanks for sharing these videos and I look forward to future content

You are awesome ! I think because of the vibration in the vacuum the copper powder moved and created friction that causes electrizity and welds the particles together ! Greetings from Germany !

Saw you on Outrageous Acts of Science! Congrats Buddy!

Best RU-vid collaboration of all time!

This is fascinating Cody, I've got a fantasy of huge dry docks in orbit cold welding ships together without using any energy.

You remind me of my first husband 😂🤣 He would get his head set on something so beyond my understanding and pursue it to exhaustion. Great video! I read about cold welding and just had to see what it was. Really thorough explanation. I cannot believe how much I enjoyed this video 😂❤

2 of my fave RU-vid's working together. awesome!

Great video Cody! Very interesting, just continue with your work :)

Thanks so much for this video! I've been experimenting with cold forging and am really interesting in cold welding.

That setup was so cool. Good effort, dude.

Awesome! I learn something new from every video you make, man.

wha? that was quite spectacular. great sciencing Cody.

Cody, they showed ya on today's brand new episode of Outrageous Acts of Science on the Science Channel. Was the one with the bang snaps(pop snaps whatever ya call em) in the vacuum chamber. When it came on I was like, "Hey! Its Cody! Awesome! As always love your vids man! Keep up the good work.

Great, demonstrative video. We see a lot of interested people commenting here, many who are familiar with physics, chemistry and experimentation. I wish more people (there are a lot) who don't spend any thought or time in this area would watch these sorts of videos. Many who don't really know any of these concepts. Maybe then there would be more appreciation for science and how much thought it really takes to have created the comfortable, privileged world in which they live.

Pretty interesting Looking forward to future results

i love AvE his videos are so funny and i noticed that both of you guys have certain phrases you like to say

Cody Slab you've done it again!

Perhaps you could use a press/clamp with a strain gauge and see if you can get to a pressure where the indium, copper, gold or steel cold weld. I also wonder if when you are smashing he pieces together, there's actually quite a bit of reactive force subsequent to the initial collision which is perhaps high enough to then break any weld that might have formed. Great video series.

whoa, you're awesome Cody!

11:20 "Possibly several hours" His commitment to science is unmatched!

Cody, it was explained to us in machine shop class that the gauge blocks stick together by external air pressure. The surfaces of the gauge blocks are so smooth that you squeeze the air out from between them and they stick like a suction cup.

Your a cool guy and have nice videos. Thank you for contributing to the fee knowledge my little bro and eventually my kids will use. Solid experiments

This is the video we have been waiting for!

Very interesting video. I had no idea cold welding was a concept at all prior to seeing your videos! also, very cool dftba poster dude

I have a hypothesis about smacking the indium together like you did toward the end. I believe​ that when you smack them together so quickly, it's forcing such a strong shock through the ingots that you're actually BOUNCING them off of each other, and they hit multiple times when you smack them together. That is what is keeping it from welding.

Hey cody, with your videos I feel like I am doing the experiment I think that EVERY scientist should film and post in youtube their experiments so that the process of learning can be shared too. istead of only the hypothesis, process, results, and conclusion. you do thouse in your videos like an actual scientific study, but by seeing you do the experiment I feel like I can learn MORE.

I love the Rube Goldberg-esque rig for pulling out the cloth

When you smash them together the surface molecules also gets squished and almost instantly rebounds. Hence the molecules are not close for a long enough time for the van der waal forces to take effect which is essential in initiating cold welding.

What I still think, the roughness of the surface is main problem in big surfaces. The attractive force is present to up to ~1x10^-12m. Repulsive force acts in bigger distance. The finest lapping is able to produce surface with roughness 20-50x10^-12m. So when you put two surfaces with this roughness on each other, they stick on relatively small amount of points of contact. When you slide these pieces you put one piece "mountains" into other piece "valleys" thus increasing the surface which is closer than ~1x10^-12m. When you vibrated the fine dust, you minimized the whole surface and increased point of contact. Plus even the force is minimal, those particles were bumping to each other. BTW I do not want this comment sounds negative or something. Great work Cody.

Hi Cody, From my experience, the gas Layers are not the main issue. In ambient air, you normally generate a molecular layer of water from the residual humidity in the air. With your end pressure, i assume baking the pieces at 110°C for an hour, you may yield some results with gold, but you have to go to < 1e-7mbar. (you need a TMP or ion getter pump for this) and a lot of time for bigger effects. It is amazing, how sticky stuff gets at the nanometer-level, and how much effort it takes, to remove unwanted stuff. If you have an oxide layer, you would have to remove it by mechanical work, or other means, like sputtering. Your results with copper is probably, because the mechanical forces cleaved the surface, exposing a clean surface, which was able to welt. The water layer is also a source of adhesion "glueing" the gauge blocks together in air.

Very cool! I think cold welding, like the formation of other chemical bonds, requires some activation energy. The joining of metallic particles together into a solid mass may be an exothermic process but it makes sense that some heat would facilitate the 'reaction'. I'm sure the impacts of the vibrating powders generated some significant friction / heat. It would be interesting to see if heating the sample a little (+100 or 200 degrees) would make a difference in how quickly it clumped up. Great videos Cody.

What's most interesting in the result with the copper powder is that this experiment says that finely grained dust will merge into lumps easily under vacuum. I am thinking of sun's primordial dust cloud. This experiment is a beautiful DIY-able demonstration of how dust could have clumped together to form our planets. Absolutely brilliant, lads!

I've heard that one of the reasons that solder paste goes off is that the solder balls can cold weld together (and thus change the particle size affecting the properties of the paste) as the flux in the paste removes their surface oxides over time.

awesome, thanks for all the vartients!! keep up the good work!

I really enjoy your content. Thanks.

An Ave and Cody collaboration would rock, get with it guys, you know you want too.....