Before passing along his inside handle to Project Egress, YouTuber Paul's Garage tested its hardiness on multiple household items, including his car. Because: "If it can pull a hatchback, it can open a hatch."
Paul's build process is fascinating; read about it below, and then watch his build video.
Artist Statement: "I have been a fan of NASA and space travel since I was young. True living heroes riding giant rockets pushing the limits of engineering and human endurance, blasting off into space beyond the reaches of the clouds, who couldn't be fascinated?
Unfortunately by the time I was born, the Saturn V was done flying. Between living a standard terrestrial life and watching the occasional rocket launch live stream, I was asked to join with other makers to recreate a part of Apollo 11 equipment. As someone who just makes random 'maker' type YouTube videos for fun, I never expected to be involved in this kind of project. I jumped at this opportunity with my inner 6 year old (all makers have one, I'm convinced) screaming wildly inside my brain. I was just given the honor of recreating the inner hatch handle of the lunar command module, and I couldn't be more excited.
I decided very quickly to cast the part in metal. Melting scrap into new exciting things in my home-brew metal foundry furnace is one of my favorite hobbies, and I thought this handle would look great in aluminum. This process is challenging and uses more steps than you would expect to make a single piece with no moving parts. It can present some unexpected challenges to overcome. As a payoff, however, I get to mess around with fire and melt a bunch of stuff into puddles of shiny liquid as part of the process. So I have that going for me, which is nice.
Having been provided with a 3D model of the part by the Project Egress team, I printed a copy in plastic a few percent oversized, and cleaned it up with some sand paper. The FDM printing process results in multiple parallel lines running around the part, and these can act like teeth, holding the part in the sand. These have to be sanded down at least somewhat to prevent this issue from occurring. This is made worse by the part having little to no "draft", a feature usually found in casting patterns to make removal of the pattern easier. Some lines were left, however. If the layer lines from the 3D print show up in the final casting, I can be reasonably sure the surface finish of the part turned out great. Details like that are tricky.
With the pattern prepared, I rammed it in a two part sand pattern. To sand cast parts in metal, a pattern must be rammed up in a special kind of sand that sticks together. The two parts are then split, the pattern is removed, and the two parts (called flasks), are put back together. This leaves a hollow spot in the sand where the pattern originally sat. This hole is then filled with face-meltingly-hot molten metal, which then solidifies in the shape of the pattern, creating your part.
The sand I use is oil bonded, called "petrobond". This is often used as jewelry making sand due to its ability to reproduce fine details and decent surfaces. To further improve surface finish, and to prevent sand from sticking where it shouldn't, everything is covered in talc, a cheap, readily available parting powder. To get the metal into the hollow cavity left by the pattern, a system of small, smooth runners was formed that is designed to reduce turbulence and keep impurities and entrapped air from entering the mold.
When the part had cooled and was removed from the mold, I decided to have some fun before sending it off. To test out how strong this handle really was, I bolted it to my fridge door. As the closest analogue to a space ship hatch I have in my garage, I'm happy to say the handle worked flawlessly. I then walked around clamping the handle to progressively heavier stuff. My bravery (possibly hubris?) eventually got the best of me, and I bolted it to the back of my little red hatchback. Hatch is in the name, clearly this is a good idea. I grabbed the handle and leaned back, and pulled that car right out of the garage using only this handle! The only thing that broke was my back, the handle was fine. If it can pull a hatchback, it can open a hatch. Mission accomplished."