I wonder if Rush & Co. consulted as many engineers and took their information as seriously as you have? Thanks for the information.

i didn't realize comparing food to epoxy was industry standard but it makes sense! that part of the video never struck me as odd. not using a big specialized curing device or vacuum mold or something like every other organization that makes structural carbon composites seem to do seemed more odd to me lol

Another amazing video related to Titan. Thanks so much for putting in the time!

Bulk density of titanium is 130 and the bulk density of epoxy resin in 20. This means the epoxy would deform under extreme loads where the titanium would hardly deform at all. These compression and relaxation cycles would cause a delamination of the epoxy over time.

My guess is that the Titan's viewport blew in. It was certified to a pressure of only 1,300 meters below sea level. Sea water then shot in, compressing the air and all five passengers into a tiny area in the opposite titanium cap which remained intact. I assume that this is the location where "presumed human remains" have been recovered. At the same time the extreme and rapid compression of air into that titanium cap would cause tremendous heat. After that the carbon fiber hull would explode. The result would be one titanium cap without the viewport, one cap with about a half ton of compressed, cooked human mush in it, the landing frame, the outer metal cover which had that fin shape and thousands of tiny carbon fiber shards scattered on the sea floor, which I believe is what has been found. All the metal parts of the sub have been publicly displayed except that rear cap for understandable reasons. The landing frame appears to be intact and straight. An implosion of the carbon fiber hull would have pulled the titanium caps inward and bent the landing frame. An implosion of the carbon fiber hull would have chopped the passengers into countless tiny shreds which could not be recovered. In a KZfaq video with Mexican actor Alan Estrada Rush explained regarding the viewport: “It's acrylic - plexiglass. It is seven inches thick and weighs about 80lbs. And when we go to the Titanic, it will squeeze in about three-quarters of an inch and just deforms. And acrylic is great because before it cracks or fails, it starts to crackle so you get a huge warning if it's going to fail.” Rush charged a 19 year old boy $250,000 for the privilege of traveling in this death trap.

What I wonder is what the temperature rating would be for such epoxy seals. I remember that the Challenger shuttle blew up because the o rings were brittle from the cold and leaked. Nothing in aerospace has such a huge pressure differential as one finds deep in the ocean, plus it's also cold down there. Even if epoxy was used instead of o rings, surely temperature would also have an effect on it so it seems important to understand what cold does to the epoxy they used.

Hey Joe. I'e found your chanel some time ago and am blown away. You're qualified, experienced, and have a way with words. Listening to you is a pleasure, even if a topic is as grim as this one is. After watching your first video I looked at your subscriber count and was blown away. You're criminally underappreciated by the algorithm. PS: I've just rememberd now: on the topic of the endcaps being forced together, Matt, who runds the "Dirty Garage Guy" and is an engineer, did some basic stress analysis of a model of the sub and it showed that the composite hull deformed significantly, being forced together, shortening its diameter due to direct pressure of the water and lenth, due to water pushing the endcaps together, additionally stessing and deforming the hull further. Maybe this deformation can help result the lack of debris from the composite on the endcaps/collars; due to repeated, heavy deformation, delamination was so heavy that it basically popped them clean off?

This video is very appreciated! I have been wanting some answers regarding this.

the sound on this video is really great, much easier to hear you.

Excellent work Joe!

Wreck investigation is very strict on what is undone and what isn't. The window would not have been removed by the recovery team unless it was absolutely neccessary, and they recovered the unpierced end cap too, so it wouldn't have been removed for weight issues. More likely the window got blown out during the implosion as the securing ring was likely only designed to stop the window falling out at/near sea level.

very enlightening discussing on your part. You help me to see that the collapse of the submersible was in an accordion like fashion. As the two end caps, which were normally separated by the nine feet of carbon fiber wrapped pressure vessel were subjected to the pressures of the dive, they were suddenly collapsed towards one another. This sudden collapse must have generated sufficient force to cause the viewing window to be thrust off of the titanium end cap. Additionally, there was sufficient force applied that caused all of the bolts to fail on both the view ports flange and the titanium end cap. Think of how people go about crushing a soda can. while some might wrap their fist around a full, opened can and crush it like an anaconda, most people prefer to place either hand on each end of the can and compress it like an accordion. Others prefer to stand the emptied can on the ground and use the Godzilla effect of stomping on the can. And then there are the select few who place their hand on top of an empty can and thrust the bottom of the can onto their forehead. My point is, the reason for the sight glass and missing bolts/flange is that the vessel collapse like an accordion with the resulting compression of the air within the vessel being sufficient to cause the sight glass flange and the end cap flange bolts to fail.

The end caps are pressing in on the CF tube trying to buckle it. It’s like it is in a press applying 43.3 million pounds-force to the end caps. The end caps would collapse inward when the CF tube fails.

Its the different expansion/shrink rates of the different materials used in Titanium and Carbon Fiber Composite. During these high pressure and low pressure cycles that the end caps and pressure hull would see, the change in thickness of each substrate would cause delamination to occur over time.

Thanks from NZ ! . was wondering about that glue they used.

Sticking end caps on a vessel with epoxy an hoping that was Gona hold, without any truss bi flange retaining bolts at such incredible pressure . Was lunacy on the high seas.

I don't think of peanut butter, but catsup and chum would be appropriate.

It would be interesting if we could find one of the other engineers involved in the epoxy application for the Titan just to get more details.

Excellent video so far, a very welcome change from the super speculative zero information bullshit that most of the Titan videos getting hits are constructed from. Also, very big kudos for admitting to your errors. The epoxy was there as a seal, its major function as I understand it was to avoid all the problems of the thick wall cylinder calculations, and ensure that the flange was seated on, and transmitting pressure to, the entire wall thickness of the cylinder, both in terms of shear and twist, but also in terms of eliminating manufacturing voids. It had the bonus side effect of stopping the end caps falling off when they were not being forced on by water pressure. A quick back of a fag packet calculation of the pressures involved indicate an order of magnitude difference between the pressures being applied across the joint, and the one of water pressure trying to force its way in. I only have two negative comments on your video, in fact. Firstly, use proper units :) Secondly, and far more importantly, the word "height" is neither spelled, nor pronounced, "heighth". Wide - width. Deep- depth. Broad - breadth. High, heigh*t*. Actually, may I use the clip of you saying "heighth" for an upcoming stupid video?

I hope they used extra crunchy.

Can point to the engineering forum where you are discussing the stresses around the joint? I'd like to join in there as well.

Plot twist: analysis of the wreckage reveals that the bonding agent was actual peanut butter.

Joe, I would have used a 2Inch Titanium mandrel, weld the caps on the ends and then wrap the compression chamber with Carbon Fibre since he was dead set on using it. Stockon's ego added 5 more lives to the Titanic

ET cetera, it’s Latin for “and so forth”.

Re: the implosion.. the pressure on the hull is trying to do 2 things, reduce the length on the hull and reduce it's diameter. By applying the external pressure to the area of the circle using the outside diameter of the hull tube, you get the axial load applied to the hull tube putting it in compression. The pressure also applies to the outside of the tube, pushing in radially. When the hull fails, it would fail in both directions more or less simultaneously. The end bells would start accelerating towards the center of the hull. The water and hull fragments around the hull also starts accelerating inward radially. Everything comes together with a massive amount of momentum and energy nearer the center of the hull. At this point (assuming the CF tube failed first) the dome would still be fastened to the titanium rings, and the window would still be in place. The next part is where the energy is released as chaos. The pressure in the center of the hull would spike and this would reflect outwards as a shock wave. This pressure wave would apply a massive force outwards on the window and domes. It is at this point I i believe the window and dome/ring fasteners failed. What's incredible here is that the dome to ring fasteners failed, and the reaction for that load was the mass of the titanium ring. The energy of the event is P*V. I calculate 240 MJ, which is equivalent to about 57 kg of TNT. I know that not many have a feel for how much that is and what that would do, but it's a lot. The subsequent events would have be incredibly energetic to say the least.

It’s actually the exact same terms we use in construction for everything from ram neck to plaster to sealer to thermal paste, hell when setting or shooting property corners, we use every term but the exact measurement, be a tenth, a hundredth, a foot or even a thousandth

I am genuinely confused what on Earth are you talking about. Stockton Rush very clearly said that it was thick LIKE peanut butter not that it was peanut butter. I have followed this story very closely and Ive not heard or seen one person fixate on the description of the epoxy.

The Titan system was probably a two equal part system. I felt it was too thick and mixing with a wooden stick was far from ideal. I like to vibrate it.

I work with Epoxy based Paints which is a 2 part paint. You have your base and your curing agent. Before you add the cringe agent the base or paint is very thick and it is just like peanut butter . The curing agent basically acts like a paint thinner when you add it too thevccmdr

I cannot believe the titanium end cap was "attached" with a slight overlap adhesive flange? There is barely a overlap lip, the carbon fiber was spun in a linear manner, no weaving. (Such little effort in design) YET -They charged $250,000 per person! If they want Return customers, a good reputation? You'd THINK they would invest in advanced engineering designs! Engineer far beyond your operating limit's! Have a bunch of the BEST "what if worse case scenario responses set up" in case something happens. Since only a FEW things can even operate at those underwater conditions. Why not have much more advanced emergency location services? Have a 2 submersible system. Use teether systems, dont operate around a messy titanic ship wreck. Let ROVs do that. Or at LEAST build your submersible so it can withstand MUCH MUCH GREATER STRESS than anything it would experience! I don't understand this type of negligence. This is supposed to carry people, it would be different if it was a unmanned ROV. But NO they charge a quarter of a million dollars per person! For what? Where is all that money going? Definitely didn't go into safety, engineering, technology resources and capabilities... It makes no sense even from a strictly business stand point?? You'd want customers & good PR for continuing income.. well they tossed that down the drain... It makes no sense and makes me so frustrated.

He used Flex Seal.

A lot has been discussed about the epoxy. This is in part, ancillary to the structural integrity of the titanium hemispherical end cap/ carbon fiber interface. By the way, your use of the term peanut butter, does not technically relate to epoxy 'thickness' but rather the 'viscosity' of the epoxy used. Choice of epoxy matters but that isn't likely what failed and also consider that the hull itself was comprised of an epoxy matrix, interspersed with carbon fibers. Epoxy is what the hull was made out of because it is the substrate material of carbon fiber. Without being able to post a picture, I will provide a verbal visual. Visualize two 2 x 4's made out of wood. One is 6 inches long and very rigid and bolted to the ground pointing up. Apply some epoxy to the top edge. Then place a 4' long, 2 x 4 over the top edge of the short 2 x 4 sticking up. Let the epoxy cure for a couple of days. Then, grab the edge of the long 2 x 4 and pull up and push down on it 1 inch in each direction several times. Call this cyclic loading. This replicates what was happening to the joints of the Titan. The center of the carbon fiber hull was displacing...like grip pressure on a beer can without crushing it...called elastic deformation...due to water pressure of every deep dive. Elastic because when releasing the pressure of the ocean, the Titan hull would return to its original free state. But repeated 'oil canning' of the hull causes the joints of the hull glued to the Titanium end caps to act like the glued together 2 x 4's lifting one edge repeatedly. This joint will degrade over time when carbon fiber is used for the hull material and diving 2.5 miles beneath the ocean surface. As an engineer, this is the kind of dynamic engineers consider for 'their livelihood'. This the type of thing we do and what we are trained for. The reason that Rush never had this design approved and validated is because it wouldn't pass the rigor of testing that replicates diving deep in the ocean repeatedly. The adhesive was likely compromised due to the 'kinematics' I explained and not due to any native failing of the adhesive used which is even helped by water pressure. The adhesive like carbon fiber itself which is a resin based epoxy, is subject to cyclic fatigue which requires mechanical 'movement' aka elastic deformation due to force/pressure of the water deep in the ocean. The vessel handled this for a handful of deep dives and then gave way because cycling loading degraded the carbon fiber and likely at the joints per the 2 x 4 example referenced. PS. a last note about the acrylic window, no bolts left and clean flanges. What we have here is a chain reaction. Another analogy for those familar with a gas piston engine in a car. What occurred due to the crushing water pressure and hull letting go was the 'instant' crushing of a volume of about 1 atmosphere...with 400 x's one atmoshere of water pressure. Water is incompressible unlike air which is compressible. So when the ocean caved in on this small cavity inside the Titan, it superheated the air and the chain reaction was an 'explosion'. That was the noise the Coast Guard heard with the noise detection technology. The explosion blew outward the conically shaped 15 inch thick acrylic window shaped like a wine bottle cork in profile to not implode in standard practice due to the ocean's water pressure but easy to blow outward when the 'piston' of water came into the vessel with it collapsing. The bolts merely relented due to exceeding their collective tensile strength. The explosive was massive. Like an atom bomb. The 5 humans inside were vaporized. The ferocity of the explosion was why the adhesive was wiped clean...what is called shear stress of the adhesive exceeded its bonding strength by several magnitudes and why the window blew out and bolts disintegrated as well. I am looking forward to the findings and this of course has captured the imagination of the public and engineers because of how our brains are wired and life is essential an experiment. Stockton Rush was a sick man because of his engineering training and was told by 100 engineers and experts in the industry that people would die in that vessel which of course was its fate.

No amount of epoxy would be safe for that sub.

Im waiting for the video where Duct tape was used for leaks!

Wouldn't model airplane glue work better than peanut butter for 6000psi applications.

if they only used GFLEX with the etching kit they used to make....Better yet some T88 structural.... No autoclave, no injection mold, They could have turned the whole op upside down, filled the ring with epoxy and not needed to thicken any of it and no voids. Still would not have saved the design flaws but this whole thing has to be a joke....great distraction though.

Typical Rush ... go for the cheapest adhesive. Dollar to a Donut there isn't a single Aerospace QPL listing "West Systems" in existence. "Adhesives" come with "Primers" and this (apparently) has none. Also, no "mix logs", no "out time logs", no gloves, dirty shop rag ... makes my skin crawl.