Spin-Casting: A Better Way to Make Rocket Motors

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My favorite saying about the dangers of a lathe came from my stepdad, who said that a lathe would rip your arm off and slap you with it twice before you could react.

You know it’s a good day when John Joseph Bizzlington Jr. II, First of his Name uploads

I find myself obliged to point out that the mixture name "Mystery Goo" is an excellent KSP reference. Even if not intended.

One video idea that I personally would be interested in would be how do you properly dispose of the varieties of waste that come from making rockets. I'd imagine chucking a failed batch of propellant in the dumpster would get you in trouble.

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I'm in a BPS video. Calling my mom to tell her I made it rn

This brings back memories! Before 3D printers were a thing, I used to spin cast silicone molds for nosecones with a perfect parabola profile. You just spin in the vertical orientation and you have gravity combined with the spinning "centrifugal" force acting on the liquid silicone creating the nosecone shaped void. I'd then use resin in the mold (with a cap on the open end) and do rotational casting to make the hollow lightweight nosecone casting at a uniform thickness. Rotational casting is just spin casting on 2 axes at the same time. I made a rig out of PVC pipe for this that worked well, but you can also just do it by hand because the resin cures pretty fast. This content is top notch!

Reliant Robin is a reference to Top Gear that strapped one to a rocket.

Joey B so committed to the aesthetic he even polished the sample tubes!

God bless Borbo the wizard, good to see he's doing better now

I really appreciate your divulgence into safety. alot of people do not understand how dangerous heavy machinery is. ALWAYS ALWAYS ALWAYS Look out for yourself and your coworkers guys.

Many people do not take safety seriously enough, so thank you for taking the time to stress the importance of it.

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As a chef why don't you use a big pastry bag or a pastry bag style of thing? They make flat plastic with a tube so you can just dump the mix they pick it up twist it and it will come out of the tube.

I do a lot of lathe work for gunsmithing, and there are a couple things I use that could be scaled up to help here. You can get live centers that are truncated cones, intended for doing external turning work on hydraulic pistons and such. I have a set ranging from 2-3” up to 10-14”. Using one of those instead of a steady rest would allow you to apply force from the tailstock to keep any more complex casting plugs or other assemblies from moving in the tube. It could also help hold the extrusion in-round, particularly with something like a six jaw chuck. Also, I have to work with long reamers for barrel making, so I have a system to introduce coolant and lubricant through the spindle bore and down the length of the barrel. I bet you could take a similar approach to feed the casing material (or propellant) into the casing from “behind” while the lathe is running, reducing mess. You could even make the chuck-end mold plug part of the system, with a bearing surface for the goo tube to rest in, keeping it from snagging on the moving case. This is an amazing project, you’re doing incredible work, and also communicate what’s going on clearly. Best of luck!

Just gotta say that you are among the 2-3 youtubeurs that give me the most excitment when a videos drops out, along with Stuff Made Here, EZ composites, and Primitive technology.

At 4:05, I feel like phrasing it as F=mω²r would make it more clear why increasing the radius increases the centrifugal force.

I was there for the explosion of the rocket seen at 13:50. One fragment of the rocket flew a few hundred feet, hit the plastic tile for the light on the hangar, melted right through it, hit UC Berkeley's table, melted through that, and hit a fuel container. We had to drag it out and it was burning for like 4 hours straight. The other pieces thankfully didn't damage anything else, but there were close calls and small brush fires everywhere. I was on the NASA SLI team whose rocket misfired literal seconds before this happened, and I'm glad this didn't happen to our rocket.

I work for Northrop Grumman where we make the SLS solid rocket boosters, and my job is exactly this, mixing liner material to line a steel casing with. We do it in over 200 lb mixes at a time. So I am very knowledgeable on this process and the process you have developed for application is very clever. We do something similar with smaller motors called slush lining, which is essentially what you're doing here but we don't spin at high speed until it cure. Another thing to point out, yes you are using this material to chemically bond the propellant to the liner, but with how thick it is, you're creating your insulation at the same time, very smart!