Monday, July 14, 2014

3D Printing Stories: Flats of Drying Apricots

[Sorry, history buffs - feel free to skip all the 3d printing and model building articles coming up.]

Here's the latest project for the 3d printer: stacks of drying flats.

The new version of the "Abinante and Nola Packing House" is getting finished. The building is now labelled as J.S. Roberts, the actual occupant in the mid 1930's. I've got the rough building done, but there's still some details... like a roof... to finish. But it's looking finished.

The J.S. Roberts packing house had one unusual feature: a separate addition contained a "sulfur box" - a sealed box where apricots could be smoked in burning sulfur fumes to preserve the fruit and keep the bright orange color. Many farm drying yards had a makeshift sulfur box. However, our packing house had the sulfur box on the third floor, right next to where the fruit would be sorted and graded. That makes some sense - the dried fruit would be brought to the packing house in sacks, and carried to the top floor for sorting and grading. If it met our packer's standards, it was dropped into bins on the second floor, and pulled out on the first floor for boxing. Having the sulfur box at the top meant that it was queasy to unload.

Now, having that third floor addition for the sulfur box is kind of interesting - it's 20 feet off the ground, and probably stuck out because of the different construction and exterior look. I took some creative license, and decided having burning anything close to the main building would be inappropriate, so I put the sulfur boxes on the far side of a small deck off the second floor. And if I've made the sulfur boxes visible to the outside, I'll also need to show the fruit going in.

That means I need drying flats - the real sulfur boxes would have taken stacks of flats each holding a layer of apricots. Drying flats are useful for other scenes on the railroad. In farm drying yards, women in the cutting shed would have halved apricots and put them on the flats; stacks would then have been rolled on small carts out into the drying yard to be laid out for drying in the sun. I've made a few drying flats by hand out of card stock and 1x4 scale lumber, but those pieces are tedious, small and fiddly. Doing a stack of 15 would be even worse. Luckily, a 3d printer doesn't know about tedious.

The drying flat stacks are about 3/8 inch wide, one inch tall, and one inch deep. The center of the model is hollow, but the individual flats are actually separate on each end. These were painted with a weathered black, then washed with Floquil grime for a translucent, white look of weathered wood. I made stacks in several different heights: five flats, 12 flats, and 15 flats. Printing some individual flats would also be fun, but I'll need to figure out how to set up the prints.

I did the 3d design for these in SketchUp, which is wonderful for rectangular designs like these. My first designs were too thin; I'd started with a one inch lumber border around each frame, but the printer needed walls to be more substantial than 0.010 inch. The image from SketchUp shows how the side rails were two scale inches wide except for the top frame. Each flat goes back 1/8", with the bulk of the model hollow to save on resin. The fruit isn't very realistic, but it does add a bit of detail.

I'm not the only one making industry-specific details on a 3d printer. Ken Harstine has been selling orchard ladders, field boxes, and fruit lugs at Shapeways for quite a while, and his models definitely inspired me to see what I can print.

Still to come: flatcars and lumber loads, straight from the 3d printer!

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