A Vent Countdown (day 35)

Continuing the recent trend of working on chest block details, I’ve built the chest vents and cut holes in the chest block shell parts so I can countersink them.

When I built the chest block parts years ago I planned out the size and position of the vents; however upon reviewing the lineart I decided that I’d gotten the dimensions wrong. I worked out what the actual dimensions should be and got started on making the vent part. This is one of those parts, kind of like the cockpit hatch, where I’m finding my way a little bit as I go.
I started by building up the basic shape for the vent – just a hollow trapezoidal solid. Not exactly brain surgery. Earlier in the project I had considered using an off-the-rack option part for the vent, but I decided against it because it probably wouldn’t look quite right, and I wanted to be kind of particular about getting it right. I cut out the basic shape from 1mm thick grid-printed styrene, with the design centered around visible guidelines on the grid so I could use the grid to check symmetry. I didn’t really think through how deep the vent should be, so I started with a generous 5mm, and repeatedly cut it down until I thought it looked right.

When I built the chest block parts ages ago I scribed in an outline for the chest vent. My plan was to cut away a layer of styrene from the chest block shell (the shell is 2mm thick, made of 2 layers of 1mm thick styrene plate, so it’s relatively easy to pull it apart at the layer boundary) and then insert the vent into the opening. Countersinking the vent would serve both to help me position the vent and give it a sense of depth and allow me to substitute a different vent part if I wanted to change the style of the build. However the old vent outline was only around 3mm tall. Looking at the lineart I determined it should be more like 5mm. So using the old outline as a starting point I measured out and scribed the new outline and checked it with the WIP vent part.

When I was sure I was happy with the position and size of the vent I cut the countersink hole in the chest. This was a little tough as I wasn’t entirely sure how to go about doing it. I started by cutting the boundary with multiple passes of the hobby knife, but it was hard to gauge how far down I’d gotten and it was hard to get anything into the cut line to try to pry the layer of styrene out. Eventually I hit on the idea of cutting a channel in the middle of the rectangle: this allowed me to cut a wider opening which helped both with recognizing when I’d reached the layer boundary, and made it much easier to pry the outer layer off.

This feels like a clumsy bit of work but that’s how it goes sometimes. My tendency is to try to plan out everything, and so I hit a wall when I don’t know how to design what I need. The cockpit hatch is a good example of this, I could just never quite get it right in plan drawings or in Blender. With the vents it’s more about nailing down some specifics about its shape. By moving forward with a part in a physical medium it becomes a more intuitive process, it becomes harder to get precision but easier to experiment with different shapes. There’s more to be done with the vent for sure but it’s nice to have a good start on it.

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