Introduction: Cutting Things in Half

During my residency at Pier 9, I asked myself how I could inject surprise, intuition, and spontaneity into my art practice using digital fabrication techniques. As I worked through a variety of processes, I found one possible answer: the cross-section. The simple act of cutting something in half does something more than just reveal its interior. It both provides information and abstracts information, pulls away the curtain and creates something completely new.

This thought has guided me through many projects throughout my residency, most of which required the use of the Omax Waterjet cutter at Pier 9. I scoured found objects from estate sales and car mechanics shops, things from flea markets and things I found on the street. I also used found objects as molds for my own castings, filling cavities like teapots or ventilation ducting with a variety of materials, casting resin into the negative space, and then cutting these castings to find out what I had created.

Step 1: Cutting Things in Half: What I Will Discuss

In this Instructable, I'll discuss the following cross-section projects:

1. Found objects: cordless and rotary phones

2. Found objects with interventions: casting into the interior of teapots

3. New anachronism: casting with an adding machine

4. Casting with cuckoo clocks plus hard candy (sweet time!)

5. Crumpled paper castings

6. Halved Dial-a-matic Hoover vacuum cleaner

7. Tube castings with ventilation ducting (plus charcoal briquettes, volcanic rock, fabric, expanded metal, aluminum...)


Step 2: Found Objects: Cordless and Rotary Phones

I remember having a rotary phone in my childhood home in Alaska, so when I found one at an estate sale in a retirement community I had a flash of nostalgia. It was pleasingly hokey, with acrylic masquerading as glass and painted plastic instead of metal. Perfect for cutting! I also found a bag of cordless phones in the garage at the sale, and couldn't resist the parallel.

In these initial investigations, my technical goals were to find out how far the Waterjet mixing nozzle could be from the material and to hone my fixturing process. I found the easiest way to jig the phones is to use straps or zip ties, but the challenge is to avoid cutting the fixtures. I was excited to discover that the mixing nozzle can be up to five inches away from the object being cut without consequences other than an increased kerf width.

You can see a lot of empty space in the older phone, compared to the compact economy of the cordless one. Both are rather surreal.

Step 3: Found Objects With Interventions: Casting Into the Interior of Teapots Part 1

The next step was to intervene on found objects by casting into their interior. I used two gilded teapots as my molds and filled them with safety glasses, rubber tubing for car parts, drywall screws, gasoline filters, crumpled paper, and scrap machined aluminum. I then filled the rest of the space with clear epoxy resin, let the pieces cure for 72 hours, and set them up on the Waterjet cutter. I realized that I could squeeze the teapots between two slats on the bed of the machine and clamp them laterally with C-clamps. The tension in the metal slats worked in my favor, squeezing the two parts together as the cut was being made so neither half would drop down later.

Step 4: Found Objects With Interventions: Casting Into the Interior of Teapots Part 2

I think of the taller teapot as my most romantic piece to date: a rubber tube connects the two sides, and its cross-section looks surprisingly like a heart. My favorite part of the smaller teapot is the gasoline filter, which fans out to reveal a complex interior.

Step 5: New Anachronism: Casting With an Adding Machine Part 1

My friend found an adding machine in a warehouse in upstate New York, and sent it across the country so it could meet its fate at the hands of the Waterjet cutter. I built a simple mold for it using MDF and cast clear epoxy resin into the cavity to freeze the moving parts and turn the object into one solid mass. I then used this same mold as a jig for the Waterjet cutter, adding angled shims to get the look of a 5-axis cut with nice compound curves. For this project I decided to make two parallel cuts so I could have a separate interior piece. I removed the slats at the far end of the Waterjet cutting bed so that I could lower my piece into the water, as the z can only go above the top of the slats by about 4.75". The right cut exceeded the soft limits of the machine, but luckily did not extend beyond the hard limits so there was no need to re-do my fixturing system.

Step 6: New Anachronism: Casting With an Adding Machine Part 2

Once the part was cut, I polished it and coated it with clear spray gloss. Here are the results.

It reminds me of an artifact that might have been discovered on an archaeological dig. In this piece, the cross-section does not really reveal the underpinnings of the machine at all. Instead, the cut edges abstract the machine, turning it into a painting that loosely references what it used to be.

Step 7: Casting With Cuckoo Clocks Plus Hard Candy Part 1

I found a vase with a cheap plastic flower in it at a yard sale one morning, and thought it would make an interesting mold. I pulled out its contents, leaving the pebbles in clear silicone at the bottom, and then proceeded to fill it with hand-sculpted hard candy. I've written a lot about this process in another Instructable, Sculptural Experiments with Hard Candy ( I topped the candy off with German cuckoo clocks and black sesame seeds and filled the cavity with clear epoxy resin. It occurred to me that the casting would get very hot, so I put my mold in a bucket and decided I would cast in two parts to keep the volume down. Theoretically this would prevent the resin from accumulating enough heat to crack the glass.

Step 8: Casting With Cuckoo Clocks Plus Hard Candy Part 2

After the first day, the casting was in good shape, though the heat had caused the candy to sink towards the bottom. Because this left a fair amount of negative space at the top, I added a top layer of glass-green hard candy, and then poured clear resin in all the way to the top.

The video below shows how the resin behaved after this second casting phase. Sesame seeds and air bubbles slowly rose to the top of the castings in surprisingly beautiful patterns.

Alas, this resin was the straw that broke the camel's back. The disparity in temperature between the two resin pours caused the glass to crack, and all the new resin poured out into the bucket. The next day I battled the bucket, trying to pull my casting out before the resin fully cured, but it was a comedy of errors. I've never worked with a stickier material than uncured resin: my glove would get stuck in the material, and then in my effort to pull it away my other glove would get stuck, and so on...

I let the resin cure for three days, and then used a reciprocating saw (Sawzall) to remove the casting from the bucket. I was going to save this piece.

Step 9: Casting With Cuckoo Clocks Plus Hard Candy Part 3

After jigging and cutting the casting on the Waterjet cutter, I polished and sealed the cut edges. I lost one side of this piece in an attempt to break the glass "mold" off the casting. On the half that remains, the glass is still in place, fracture lines and all.

The piece ended up looking like shards of amber trapped in a vial. It has the look of a time capsule, but the smell of burned sugar emanating from the cut belies this simple description.

Step 10: Crumpled Paper Castings Part 1

I developed a method that is similar to the idea of filling a cavity with objects and then filling the negative space with resin. The idea is to replace all the resin with air, and instead use resin to stiffen and strengthen a material that otherwise would not have the right amount of structural integrity.

Around this time I was conducting research on crumpled pieces of paper. Mathematicians have gone so far as to study the creases in crumpled paper to develop models that will predict how the paper will behave once it's undergone this stress. But even though physical equations can describe the dynamics of some types of crumpling, the ways the creases arrange themselves in specific patterns remains unpredictable. This piqued my interest in studying the cross-section of crumpled paper, so I decided to try soaking paper in resin, crumpling it, letting it cure in a mold, and then cutting it.

My experiments were successful. Technically, I learned that garbage bags (polyethylene) are a great mold liner--resin won't stick to them. My castings had so much air in them that I didn't have to worry about heat melting the bags. I used cardboard boxes and 5-gallon buckets as my molds. I tried both construction paper and typing paper, as well as typing paper that I striped with ink or marker to highlight the contours of the folds. I tried Waterjet cutting one sample, and though it worked, the piece remained waterlogged for days. I had better results with the bandsaw.

In the pictures above, I used an acrylic wash with a sponge brush to create striped patterns on both sides of typing paper. I wrapped my arms in plastic bags to keep resin from touching my skin--this otherwise would be a rather toxic process.

Step 11: Crumpled Paper Castings Part 2

The results, as well as some earlier experiments with construction paper and highlighter stripes on typing paper.

Step 12: Halved Dial-a-matic Hoover Vacuum Cleaner

This particular vacuum cleaner appeared, disappeared, and then fortuitously re-appeared outside my friend's house. This model is from the early 60's, at the time that the Hoover company decided to develop economy models without the bells and whistles of previous iterations.

I decided not to alter the machine before cutting it: it really didn't require any augmentation. The jigging system was based on my previous trials using lateral clamping force. I was careful to set the jet to 6" of mild steel while it was cutting through the motor, but I sped it up significantly once it was through that part. I took the vacuum cleaner off the machine before I was through cutting the handle so that I could see what it would look like splayed out, but decided that this piece would be more effective if I went through it completely.

In the end, as with the old rotary phone, you can see how simple this machine is.

Step 13: Tube Castings With Ventilation Ducting Part 1

After making my geometric cylinder piece, I decided to challenge myself by casting into a distorted cylinder, or a tube that changes direction multiple times.The tricky part was finding a material that could withstand the heat of high volumes of resin, stay watertight, and remove easily from the casting afterwards. These three criteria helped me settle on ventilation ducting. I set up small-scale trials with aluminum crimped ducting, clear plastic ducting (for temperatures up to 250 degrees Farenheit), and foil ducting lined with plastic. For these three trials, I filled the molds with aggregate materials I scoured from the waste bins at Pier 9: pieces of wood that I cut and painted with multiple colors, broken rocks, discarded laser cut acrylic, aluminum cut-offs, and fabric. All three casting materials worked well: no leaks, removed somewhat easily from the casting afterwards, and no problems due to heat. I liked the clear plastic and crimped aluminum best, so I decided to work with these on a larger scale for my final project.

For the larger scale pieces, I gathered the following materials as aggregate: yarn, wood, salt, volcanic rock, charcoal briquettes, expanded aluminum, discarded 3D prints, sweatshirt material, and vinyl. I set up the tubes on plastic trays and over buckets, sealed the bottoms with silicone, and then cast a 1" layer of resin at the bottom to ensure the seal would hold. Two days later, I poured in resin to about half the height of each mold--a few gallons in each tube.

The problem with small trials is that volume, especially when casting, is a critical factor. When I increased the volume of the resin in my castings, this increased pressure caused the crimped aluminum to leak in multiple places. The clear plastic would stretch, like a snake swallowing a horse, and then eventually puncture with the pressure of the objects pressed against the interior walls. I found that I had to reinforce my molds with silicone and duct tape, and even then reconcile myself to a few leaks here and there. In the future, I believe I could still use these materials as molds if I worked with multiple layers and a resin that cures quickly, pouring a 2-3 inch layer every day for a few weeks.

That said, I was very excited to see the castings once I had cut them open. I was interested to see that the red volcanic rock in each casting colored the opaque white resin and turned it into the color of apricot ice cream. This was unexpected, but worked well with the rest of the color palette.

Step 14: Tube Castings With Ventilation Ducting Part 2

The results. These pieces remind me of Chinese landscape paintings, and the serpentine tube almost references a scroll.

Step 15: In Conclusion...

Many digital fabrication processes--almost by definition--require a certain level of predetermination. This is usually a good thing: you want to see your part simulated in virtual space before you print or machine it. But in the fine art realm, it is sometimes the case that this physical execution is perfunctory. If something is fully realized in virtual space, its concept doesn't necessarily change once it's been built.

My experiments with cross-sections have allowed process to integrate fully into my work. Making the art is an investigation, not an execution, and the finished product is not always fully known.

In the end, I have to cut open my art to see what I've made.