Gaurab Chakrabarti

We spent $15,000 on billboards targeting one person: the guy controlling all the chemical spend at a saltwater disposal company in Texas. We mapped his commute and bought every billboard between his house and the oil field. When we finally called, he said "I see your billboards everywhere." That landed us our first oil field contract. At the time our entire operation was a $10,000 reactor built from PVC pipes from Home Depot, turning corn sugar into industrial chemicals. People keep trying to throw it away. It still works. That leaking reactor started a multibillion-dollar company. @ycombinator visited our plant in Houston. The original PVC reactor is still on the floor next to the Bioforge.

I build chemical plants. A leading-edge fab uses more than a hundred distinct gases. Specialty gases are a $5B industry. Semiconductors are a $1T industry.

China holds 51% of global production capacity for tungsten hexafluoride (WF6), South Korea 24%, Japan 18%. Fabs use WF6 to deposit the tungsten contact plugs inside every advanced chip.

Making WF6 takes tungsten and fluorspar. China mines about 60% of the world's fluorspar and controls its export. Exporting key tungsten products from China has required a license since February 2025. The U.S. has not commercially mined tungsten since 2015.

A specialty gas plant takes years to build. Qualifying its output at a customer fab can take a year or more.

America needs to build the specialty gas and chemical plants for its fabs now.

King Slide, a Taiwanese maker of kitchen drawer slides, owns 70-90% of the market for high-end AI server rails. On Oct 30 it approved more than $600 million for what it plans as the world’s largest rail factory.

If you were building a King Slide competitor, you could buy the steel and the steel balls. You would have to build the molds, the stamping and plating lines and the assembly machines yourself. You would also have to design around its roughly 3,750 patents.

A server rail works like a drawer slide: three steel strips nest on steel balls. The two rails on either side of an AI server are 6.1 mm thick and hold a chassis of more than 40 kg. Each rail has more than 100 parts, and none can be off by more than 0.02 mm. Pulled all the way out, the rail holds the server from one end, and Nvidia’s next racks are heavier while the rails have to get thinner because liquid-cooling pipes take up the space.

Nan Juen, another Taiwanese furniture-slide maker, had made server rails since 2002. When it went after cloud servers in 2012, it found no major customer for six years because the brands had already picked their rail suppliers. It reached Nvidia’s GB200 rack in 2024.

A rail sells for under $100 and protects a rack that costs millions. In the second quarter King Slide’s gross margin was 87.4%. It still sells kitchen drawer slides.

The only rules are the rules of physics

Comcast is turning millions of home WiFi routers into motion sensors. Once customers opt in, Comcast can share their data with police without telling them.

I went through med school. Here's one case where I wouldn't mind my privacy being interrupted: sleep apnea.

Researchers in Hong Kong measured breathing rate with ordinary WiFi at over 98% accuracy.

A router’s signal bounces off the sleeper’s chest before it reaches another WiFi device in the room, like a phone or a smart speaker. At 5 GHz, the wavelength is ~6 cm, so a 5–10 mm change like breathing can be enough to measurably change the signal. Breathing repeats 12 to 20 times a minute, so software can tell it apart from other movement.

With sleep apnea, your breathing stops and restarts again and again while you sleep, and left untreated it raises the risk of stroke and heart attack. About 80% of Americans with sleep apnea have never been diagnosed. A night in a sleep lab, wired to sensors, costs around $3,000. Judged on a single night, about 1 in 5 people get the wrong result, because apnea changes from night to night.

MIT built a bedside radio that transmits at 1/1000 the power of a home WiFi router, and in a 2024 study of 880 patients its apnea count came close to their sleep-lab results.

WiFi signals already fill your bedroom. What if they could help you find out whether you or your loved ones have sleep apnea? WiFi can’t measure blood oxygen, so it would only be a screening test showing who should go visit a sleep lab.