Air-tight vs. Vacuum-tight 

Multi-reply: "cross-tighten with a torque wrench" - As of this post, I have 40 comments suggesting a torque wrench and approximately 50 recommending a star- or cross-tightening pattern. I hear you. In undergrad (maybe sophomore year?) I was helping to service a piece of vacuum equipment and was actually corrected FROM using the star pattern. I was taught that on these copper conflat flanges, "cutting in" the knife edge linearly by tightening in a circle was the way to go unless you had an absurdly large flange (which this is not). Trying to get a UHV seal with these gaskets is nontrivial, and if you have a system that works, you stick with it. I also know people who cross-tighten their conflat and get great results. In applications like this that are super-finicky, any change to procedure comes with risk. if it aint broke, don't fix it. - During this opening there were maybe 6 or 8 flanges open, and only one of them leaked, and the flange that DID leak had already been problematically leaky during previous openings, so I don't attribute the leak to a problem in tightening but more than likely, a scratch on the flange knife-edge that requires you to torque the gasket down past spec to fill the extra gap with copper. - Regarding the torque wrench, in many many locations on this system, it's almost impossible to fit a regular wrench around these flanges, let alone a necessarily bulkier torque wrench. This flange probably could have been handled by an open-end torque wrench, which I guess I assume exists but have never seen, but in general to work on these academic systems you need to develop a feel for it. Notice how I'm barely moving the wrench with each tighten. "you are wasting helium" - This is actually an extremely common and extraordinarily critical industrial use for low-purity helium. THIS is what the party balloons should be saved for. This method was developed to detect leaks so small they don't generate bubbles, noises, or other observable airflow. we're talking about a handful of atoms weaving their way through cracks in apparently solid pieces of metal. I've found a leak straight through a stainless tig weld on this system using helium. Amazingly enough, a LOT of the semiconductor industry depends on being able to create high quality vacuums for processing.

"If tightening it doesn't work, tighten it more" -Engineer

"you may assume a perfect vacuum" *engineer cries in relief*

Im really glad Tom Scott encouraged us to watch this in his most recent newsletter, because its fascinating stuff; I never considered how much such a insignificant leak could multiply so much under a vacuum.

"hey whats inside this thing?" "nothing, truly nothing"

Fantastic video. Clear, methodical, and you walked me along the entire troubleshooting path. Well done!

“I could talk about lab equipment for hours and hours” I for one would love to listen about lab equipment for hours and hours. Even if you posted barely edited ramble style videos about niche and specific lab equipment, i’d definitely watch them

Previous semiconductor worker who delt with vacuum and pressure tight vessels and pipes. -Pressure tight is way harder, especially when the differential is 100psi or more, and silane, hydrofluoric acid, anhydrous ammonia...you know the things that dissolve humans or reliably spontaneous combust in air. With a vacuum you have chances to mess up, with pressurized death gases/liquids, you have 0 chances. Also helium and hydrogen pressure tight is the worst, but we usually used helium to test connections of pies to contain worse chemicals before putting them into production. That being said, randomness from the machines vibrating, and human error caused leaks and the fun beganafterwards.

"the world is running out of helium!" "But what could you need it other than for making squeaky voices?" "Scientific purposes!" "Like what?" "Releasing it into the air so it makes everyone in the lab's voices all squeaky"

Gordon doesn't need to hear all this He's a highly trained professional

I'm in no way, an engineer. But I loved this well explained video. Thanks for bringing us into your lab, and simplifying the process for us!

I had the privilege of working on the upgrade of a fusion reactor in the UK. During my time on the project the reactor was being checked for leaks exactly like this. Totally fascinating engineering. Brilliant video :-)

The gasket no atom can pass. Hydrogen: *is that a challenge?*

"We use it to grow crystals" *breaking bad music plays*

We make quadrupole mass specs at my workplace. I love hearing an outside view on how they work and the leak test process as well!

As someone keeping track at home this is a great watch

Gasket: "NONE SHALL PASS" Hydrogen: "hold my beer"

I'm surprised you tightened the head bolts sequentially around the head rather than in a star pattern to avoid uneven distortion of the gasket. Any reason for this?

I started research in a lab this semester using a gravimetric microbalance and mass spectrometers as well, the microbalance uses the same copper gaskets as you are, albeit at a much less perfect vacuum. It is so cool to see the stuff I use in different labs as well

Thanks for a very informative video! I spent a couple of years working as a technician at a scientific research facility and often enjoyed wandering through and marvelling at the beam pipes, examining some of the sensor and control equipment and was struck by the constant hum of the various vacuum pumps which had to run continuously to keep the pipes at a near-vacuum as a particle beam was injected.

I finally managed to get a He leak detector for the lab I work at. It is a Varian that was made in about 1985 and needed some work. I managed to get it up and running, and boy am I glad I got it. There is a fancy room that we put together and it took 2 guys 3 weeks to get it mostly leak free (I used that to help justify the leak detector). I later needed to do some modifications to the room which meant finding all of the leaks that were sprung, and it took me about 4hrs to be confident that the room no longer leaks (this included a few leaks that were missed by the previous guys). I put that in there in my status report email as a sort of "I told you so".

Glad that this channel is now appearing on my Recommended! Fascinating videos!

I absolutely love your videos, and I've only seen a few of them. You're not only good at what you do, but you're really passionate about it and very excited about it, and I love it.

This is so cool! I’m currently doing my PhD in physics and my friend here works with positron annihilation Auger spectroscopy, so they use a UHV system that measures what comes off a target with a ToF tube. He was talking about the flanges and cleaning the system the other day but I never really truly understood the work that goes into maintaining it until now. I do simulations all day so this is all alien to me! Love all the replies from the scientists in this thread. We’re all just geeking out together and it feels great.

Great video! Would love to see more of this. I’m especially curious how such a high vacuum is achieved besides having perfect seals.

I've just been continuously watching vids on this channel throughout my entire day, I can totally see you hitting 2^20 subscribers very, very soon

I think your work related stuff is some of your best content, it may be complex, but you explain it in such a good way that its more entertaining then the less technical stuff.

One of the generic task I do during my daily job is designing of o ring seals for high vacuum chambers for semiconductor tools. And this video is very precise, informative and entertaining at the same time. Keep up the good work 🙌🏻

I would literally pay for content of this quality released on a once a month/nile-red-type basis also, touching on superlative topics, like whatever would be considered a catastrophic failure in this system, would be super interesting.

Mass spectrometer? Making crystals? *Flashbacks to that one incident in the anomalous materials lab in Sector 7G*

I used to work for a company that built large vacuum chambers. leak checking and fixing welds is a whole other kinda fun.

When I was working on my chemistry PhD, one of the profs had a ultra high vac system he used for is surface chemistry research. I had a class with him where we covered his to find a leak with He. 10^-12 Torr is tough to obtain. Breaking vacuum, cleaning and pumping down is certainly a lot more involved than with my GC-mass spec.

As someone who works in semiconductor equipment manufacturing I cannot imagine trying to keep vacuum flanges clean in a non-clean room environment

Totally know the feels. Had a vacuum drop in my ToF-SIMS from 10^-11 to 10^-8, which was screwing with our cesium gun. We were up for maintenance anyway, so we went with the invasive option and just changed all the copper gaskets. Fortunately after putting it all back, there were no leaks!

I worked on an STM during undergrad, and it's interesting seeing so many of the principles I learned in that lab being reflected here. Same copper gaskets, same residual gas analysis, same pumps. I mean, that's not surprising for obvious reasons, but it's still interesting to see.

Gordon this is amazing to see! I’m also in the CVD field, and battling leaks is also a constant thing. Thankfully we only stay in the milliTorr range. I want to see more of this!

I used to work on an ultra high vacuum system. We regularly had to vent and open the system to replace test samples etc. I'd love to see a video on your method for pumping down the entire system.

I refer to Vac-Seal as "Liquid Shame".

I work with a few guys like you, who can just talk and talk and talk about the equipment they work with. Always fun to ask them questions! Really interesting video!

Really cool video, I had the occasion to test seals for spacial equipment before using a similar method and thought about it immediately but you explained why it's used very well

Amazing that molecules can squeeze their way through seals in a near perfect vacuum, considering it's only ~14.7 psi on the chamber.

I knew nothing of vacuum chambers and now I feel like I could machine my own that could be half as good as this. You are an amazing communicator.

I worked in the mineral assay industry for many years, and mass spectrometers were pretty much the pinnacle of available instrumentation for the purpose of trace element analysis... for your machine, it's a leak detection accessory. Mind blown.

When you were talking about the epoxy seal, all I could think was “FLEX SEAL! IT EVEN SEALS TO PERFECT VACUUM”

Selenium huh, What are you making? perfect single crystal optoelectronic components?

This was very interesting. You are a charming and effective host. Thank you for sharing!

Keep up the wonderful work, love seeing someone passionate about what they do. And as always, great presentation

So cool! I'm always amazed at how scientists find simple solutions to problems that seem impossible. Way cool!

Thanks for bringing up my memories on working with UHV equipment on university. Memories of many, many bolts, some broken feedthroughs and unreal toughness of platinum wires. And waiting for right pressure to actually start the second and third stage pumps. Good memories :)

I used to work with high vacuum equipment myself--ironically, making parts for quadrupole mass spectrometers! Our vacuum requirements were a little less extreme than yours ("only" in the 10e-7 to 10e-8 torr range, so we could use rubber gaskets) but all the principles were the same. I may point people to this video in the future when I have to talk about my old job!

I like how real you are, you approach your videos as a person living in real life, rather than masquerading as something you're not like most people do

Soo cool to finally see someone that I can relate to regarding the daily grind. I deal with this on the daily as well. I only work with 1x10-5 in an 18"x18"x18" chamber though. We use a little Varian helium leak detector to check for leaks. Great idea with the bag to concentrate the helium. We're using the ours to perform elevated temperature (2400°F) tensile tests on high temp alloys and more recently single crystal Niobium, so we're in and out of it about 4x/day. Keeping it clean is a chore!

This guy gives me major "Jake from Avatar" vibes, with his appearance and the camera angle and content etc.

“Ultra High vacuum” Brought to you by the guy who created “extra extra extra large” the size 😂

Thanks! Now I can finally fix that pesky leak in my MBE chamber I keep in my basement. 9/10 customer tech support.

Absolutely fascinating !!! I worked in a company that sold and serviced vacuum equipment.......but nothing quite on the order of what you work with. Regardless, although not part of my responsibilities, I had to learn about vacuum equipment to be able to discuss leakage (and other types of) problems with the engineers who were tasked with producing solutions for our repair people. What I DID learn was that although everyone thoroughly understands pressures above atmospheric pressure, very few people (including many engineers) have a real problem understanding/coping with problems concerning negative pressures. It seems that we're hard-wired to work with positive pressures. I had to sit with some engineers and use my semi-pro knowledge of negative pressures to get those engineers to "re-engineer" their thought processes. They all understood the principles theoretically but couldn't make the mental "leap" to practicality. It was certainly an ego boost for me to be able to see the "light bulb" come on over an engineer's head when my "teaching" finally sank in. Ah, the glory days........before I retired. What a great vid !!!

great video! Love hearing you talk about the handling and operation of these high tech devices!

Very interesting video. I would love to see more.

I was in a lab that had both Ebola and Anthrax... So I thought that was pretty fascinating. What was probably more fascinating was how casually I was invited in there..... The professor who worked there told me that once he retired, he planned on making another lab in his old garden shed. I told him "That sounds absolutely wonderful!"

I'm just a computer programmer but I used to work with TEM scientists and I could listen to them talk vacuum all day. :)

Awesome! I'd love to watch more cool info about your equipments and research. You could explain how it works and the principles behind it. Keep it up please!!

Awesome and interesting insider look. Thanks AP!

This reminds me of the time where I assembled the caging for the PS-BGI project at CERN for the helium leak test. Now I understand a lot more why I did that and what was happening.

Like so many others, this popped up in my recommendations the other day. So happy to have found this channel. Wish I studied more STEM subjects in high school, I'm really fascinated by the world of applied physics

I do indeed find this stuff very interesting. Thanks for sharing it!

This is absolutely fascinating stuff! Thanks!

Hi friend. You brought back memories from f the MBE work I used to do at UCF. AlGaAs laser diodes grown in a Veeco Gen III. One time we spent two days looking for a leak in our shutter assemblies. Lots of jard work in general. Thanks for all your content.

That is so cool! I am a microtechnologist myself, and of course we had this topic in school, but I have never seen a MBE apparatus myself! Thanks for showing that.

"Where's the leak, Ma'am." -Patrick Star

I found this extremely fascinating! The way the gaskets are deformed like that to create that much of a seal is so cool! (I’m such a nerd)

As a plumber and gas fitter, leaks are the bane of my existence. This was very interesting.

I used to work at a pharma site looking after their freeze drying plant. We used the exact same method to find leaks on the vacuum chamber, although we attached an external helium leak detector to the equipment.

Yesssssssssssss! Talk about the work you do that you are able to!

Idk how you managed to make a video about fixing a leak interesting, but you did.

Neat to see the flanges and gaskets I make in practical use. Awesome video!

As a vacuum engineer for LIGO this was a well done video! Now imagine trying to leak hunt down a 2.5 mile long vacuum arm...

Even if what you're explaining is very simple, it is very interesting! Thanks:)

These videos keep blowing my mind! Love it! (Steve Mould sent me)

It's not "obvious" that just because someone works on something, that they find it fascinating. I've run across co-workers in my field of technology who found it an absolutely excruciating bore, but kept at it for the salary. I always felt really sad for those kinds of people. But all of that to say, consider yourself lucky that you're able to work on complex and intricate technology and ALSO find it endlessly fascinating. Cheers!

I am an ion implant engineer and leaks under high vacuum is one of the most common fail modes. This is a killer video

I did indeed find this as interesting as you did!

That uhhh, “potato cannon” looked a little sus lololol

This IS my new favourite channel! Awesome

Spent the first year of my career in machining at a shop that made components like this for the semiconductor industry, it's nice to finally see someone showing how a knife edge seal works, the thing that was always so mind blowing to me was the hours we spent hand laying the finish in a certain direction on oring seal grooves so that we didn't create a leak path. Very cool video

Amazing content. Keep it up :D.

Yes, more about the system and technology

I did vacuum testing for about 3 years. I was only testing at high vac but we also did thermal testing in our chamber. That brings in a whole different issues with out-gassing. We’d always having issues maintaining our required vacuum level when going to hot temperatures. We also did our leak checks with IPA wipes. It never really worked too well but tightening or replacing a gasket was fairly easy and worked every time. It also takes about forever to heat things in a vacuum when it’s only bolted to a plate.

I really glad to see this video i am a mechanical design engineer, year 2016 i had been working in a company who made ultra high Vacuum equipments at Bangalore.

Greetings from a fellow MBE engineer :p I work also on the RIBER system :)

This is my first video but this is such a good video passion is the best entertainment.

I work in semiconductor and we use a helium leak checked just about every day. Super neat hearing other places it gets used, cause I’d never seen one outside of the building I work in

Nice video! This brings me back to my time as a service engineer for scanning electron microscopes. Maybe you could do a follow-up video on how such a high vacuum is achieved? Like the comparison between rotary, diffussion and ion pumps and how they all need to work together to create this vacuum. And the effect of an ion pump bake-out. Keep up the good work!

NEXT EPISODE: Fixing the space station with a steel wire

"Actual engineering" ... "the real science"... you know you're talking to an engineer when they use these terms.

I found your channel over the golfput analysis. So far I've been very intrigued by everything you do.

I’m studying chemical engineering right now. That system looks really cool, really happy I found this. Definitely subscribing and looking more into these types of systems!

This is supper cool! I would actually love to know what kind of pumps and for how long they need to work to remove “all” atoms inside the system

silver plating is not for corrosion resistance, it is used as an anti-seize in high temp aplications

Fascinating video. My friend ran a precision optics shop and had to apply various coatings to glass under vacuum. He said that working with high vacuum was an arcane art akin to black magic!

Super cool informative video. I've recently been welding stainless fittings for an ultra high vacuum application for a company near my shop that makes xray equipment. Just for their r&d department. Neat to see the process of how they are checking my parts for leakage. All copper washer, knife edge flanges. I have to be really careful about my grounds while welding to make sure I don't exit the flange on the knife edge and cause a blemish on that edge.