You don’t think of hobby-grade 3D printing as a good method for creating rocket nozzles. But [Mister Highball] managed to create a copper nozzle using a common printer, a kiln, and some special copper-bearing filament.
The copper filament is about 90% metal. Virtual Foundry recommends preheating it before printing and you have to sinter it in an oven to remove the plastic and leave a solid metal piece which will, of course, shrink.
The results were not great at first, but the final run looked pretty good. You’d do well to take note of any advice on using the filament since it is quite a bit more expensive than regular PLA. There are clearly some very specific steps you need to follow to get good results.
Of course, you also need a kiln and the other equipment you need to handle molten metal. While it is impressive that you can create a metal part this easily, it still isn’t as easy as a normal print and it isn’t much easier than simply casting the part using a lost PLA technique.
While 3D printing rocket parts isn’t a new idea, earlier efforts haven’t used cheap FDM printers. We are looking forward to having a real metal 3D printer one day.
My cousin Dexter and I, both our dad’s having small machine shops at home whie empoyed by the Dow Chemical Corporation, Magnesium Aerospace Division at Bay City Michigan. They bring home bocks of DowMethal@ blocks of machined scraps and we’d machine wondrous solid fueled nozzels never getting hot enough to ignite usually camelied sugar and potassium nitrate.
I hope he tests it in his attic again!
Why doesn’t anyone in the DIY space just make an aluminum nozzle form, plasma spray torch it with titanium till it is thick enough then drop it in sodium hydroxide until the aluminum mandrel is gone? They did this in the 60’s.
That process doesnt sound like DIY space
Plasma spraying titanium sounds like decent vacuum gear would be needed or at least a very inert environment. Just drilling the stuff nearly set the shed on fire once :)
But why would titanium be good? For a static rocket, tungsten would be way better. Less melty and way less flammable/reactive. Can be brittle, so perhaps a bad choice also.
Yes, doing titanium might need a box of argon so as not to get a bunch of white paint pigment instead of a nozzle. No vacuum needed though. It is a common process used in machining shops to put hard coatings on metals. It uses an oxyacetylene torch with a hopper of metal powder or I would think an electric plasma torch. There are lots of powders, including ceramics. https://www.youtube.com/watch?v=3Tu4qqKB0EA
Then I wonder how hard it is to plate something onto an aluminum mandrel like chrome followed by ??? I’m starting with aluminum because you can remove it chemically pretty easily. I wish I had the time to try some of this properly.
The aluminium drip tray from my BBQ has been through the dishwasher a few too many times and now looks a bit worse for ware. Didn’t think they were supposed to be particularly caustic any more.
2 things here – the important life philosophy that if anything can’t survive the dishwasher it’s not worthy of being a cooking implement – and maybe we could make rocket nozzles in the dishwasher.
What you mention is more flame spray and generates a fairly interesting microstructure (pile of squashed pebbles – sintered if done well). The notion of a plasma coating I envisaged is where a film is grown – microcrystalline/amorphous/glasslike depending on conditions, but it does indeed requite a vacuum. Usually much thinner than the flame spray techniques.
Accidently plasma coated numerous things. Too much energy released in a vacuum chamber and all of a sudden all the insulators/windows are covered in gold/copper/tungsten and nothing works. Coke works pretty well to clear the stuff off without etching the surfaces. Just enough phosphoric acid. Just don’t drink it after.
Hmm, I replied to this, but it seems a magical internet gremlin ate the post. Grrr.
Flame spray is cool. But plasma coating is also done with vacuum. I’ve only done it by accident – coating vacuum windows with gold/copper/tungsten (as well as everything else in the chamber) when far, far too much energy gets loose. All in the name of science when turning up the voltage on an experimental x-ray generator and ending up with an arc rather than a nice electron beam.
Coke is pretty good at cleaning the vacuum windows without etching the glass. Putting them through the dishwasher works fairly well also but annoys health and safety.
I do realise the electric arc method is sometimes called plasma coating – but it’s not a plasma. Just lots of evaporated metal with maybe a little tiny bit of ionised gas thrown in. Too much exposure to physicists leads to being pedantic about the definition of plasma :)
The oxyacetylene torch must be vaporized material as well. In that Abom video he puts on quite a think layer. Thick enough to turn it to the final dimension. I got the idea or technique from something saw in NASA Tech Briefs wayyyy back and IIRC it was for little nozzles for attitude control jets.
I too have coated the insides of chambers with crud when borrowing a simple setup for plating electron microscope specimens with various things and used it to plate some parts with indium or something for high vacuum and neutron something. Basically on old heavy bell jar and a titanium boat for the source material. I cleaned it when I was done and the researched had a fit and said now it would implode, so I told her not to worry because I used 00 steel wool and sand paper and that glass doesn’t behave that way under stress :-) Plus it had a plexiglass and steel mesh cage. But they get the notion that an implosion of that size is like a stick of dynamite or something.
The grad students at UKAEA built a fusor for some reason. Totally wrong place to do it – as fear of neutrons and x-rays meant H&S wouldn’t allow them to wind the voltage up.
It does look cool, and as a science prop, works great, allowing school kits to fiddle with a few things to change the glow in the centre.
Mentioned as one of its strongest points is a slow sputtering on the inside of its bell jar too.
Perhaps gold would be better.
Now send a few pieces to CNC Kitchen for strength testing.
Some sawing, polishing etching and micro photography of the structure would also be nice
Why not make a multi-part form and just cast it?
Or use lost wax or lost PLA method. Spending this amount of money to 3D print a small part seems to me like great waste…
Agreed, I feel like it would be cheaper to just set up a foundry and a crucible for lost wax casting. Although copper looks difficult to cast, it can’t possibly be any more difficult than this setup. Then at least you can reuse material that isn’t up to snuff.
But hey, this is still neat, and maybe for their use case it makes more sense.
It was an follow up to other testing. The point was to 3d print a rocket. Why? Youtube. I have been following the guy for about a year. Hes great. It is more about exploring the concepts in a way that is engaging.
Copper is ridiculously easy to cast. Not hard at all.
The 3d print nearly direct to metal has some advantages with some geometries it seems to me. But as this looks to be remarkably simple thing to cast, and easy to process the casting gates afterward I’d agree this seems like using the wrong method – but if its the method you can do with the tools and understanding you have its never the wrong way…
While it may not be a DYI, ExOne has been printing in copper for some time now doing binder jetting. They do a wide range of metals, silca carbide, and ceramics. There’s a job shop where you can submit a design to be printed or you can purchase a machine.
This post is an engineering conceptual proof, it doesn’t necessarily claim to be an appropriate engineering application. We all need to think bigger. i.e. You can’t cast or machine embedded comformitive cooling channels, or generators.
Also, the described process can work with Any material that will sinter. We’ll undoubtedly find new ways to solve old problems. We’re no longer limited to Mills and Lathes. It’s time to move on and step outside the box.