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Project exit casting hatch handle

Update:08-01-2020
Summary:

For those not familiar with Project Egress, it’s a cele […]

For those not familiar with Project Egress, it’s a celebration Duplex Sand Casting  of the 50th anniversary of the first Moon landing that aims to recreate an important artifact from the mission: the Unified Crew Hatch, or UCH, from the Apollo 11 Command Module Columbia. Forty-four makers from various disciplines have been tasked with making the various pieces of the , and each one is free to use whatever materials and methods he or she wants.  chose what will probably turn out to be the consensus material  aluminum  and decided to play to his strengths by casting the part.

The handle itself is a chunky affair, as one would expect from something designed to be handled by an astronaut.  started with a printed version of the handle and created a two-piece mold in casting sand. The original part was probably machined, which meant that it didn’t have the draft angle that cast parts are supposed to have to make removal from the molding medium easier. [Paul] lucked out and got a perfect mold, and a perfect pour from silicon aluminum to boot.

All the casting needed was a little cleanup and some holes to bolt it to the door.When you cast metals, they shrink as they cool, so if you need to cast to a final dimension, you build your mold oversize, and Starrett is willing to sell you rulers to help lay out the mold.Many times, people make a master mold, then cast that in silicone, then cast wax into the silicone, and then burn out the wax as they cast aluminum into the space. In that case you need a double shrink ruler, one for the wax shrinkage and one for the metal.

And for anyone out there with the resources, go to the air and space museum! I just left DC today after a weekend visit, but even a few hours are well worth it. You can look at things on paper, but the scale alone is difficult to comprehend until you’re standing right in front of something – In this case, the gemini module. Not very impressive, until you imagine it perched atop a full saturn stack, ready to rock  The smithsonian can’t fit one of those, but they have a full-scale mockup of skylab, which was just the second stage, and just around the corner is a scale model of the whole thing – putting it all together in your head gives an entirely new perspective on things.