In my sophomore year of high school, while living in Rome, I was introduced to the hookah. Although I’m not a smoker otherwise (only the occasional cigar, on special occasions), I love hookah. It’s a naturally social activity that chills people out, and isn’t an end to itself – you smoke while you talk, not talk while you smoke.
Fast-forward 3 years, to the spring of my freshman year of college. I’d been lusting after a hookah for some time, although I’d always been turned off by the obvious low quality of the materials in commercial hookahs – unknown metals, attached with shady solders. Furthermore, I really didn’t like the aesthetics of commercial hookahs, which are almost uniformly elaborate and classically styled. I had completed the machine shop safety course at Swarthmore in the fall, and had been working as a machinist’s assistant since. I figured I might try making my own hookah, as an interesting design and fabrication project.
I started this project with three major goals in mind: 1) to use safe, inert materials throughout the entire hookah, 2) to make the hookah modular, so I could attach flowmeters/chillers/etc. later on, and 3) to maintain an appropriate “engineering” aesthetic. Requirements 1 and 3 led me to select grey iron for the bowl, Pyrex lab glassware for the vase, food-safe dishwasher piping for the hose, and stainless steel for the body, frame and handpiece of the hookah. This last selection, though I didn’t know it at the time, would prove to be a lot more trouble than I’d expected – although I would probably not suggest this for first-time machinists, I did learn a lot about fabrication through this.
Picture 2 above shows the neck joint of the hookah, which caused me the majority of my problems with this project. The neck joint consists of an internally threaded collar, which the base attaches to, and an inner plug, which is threaded to match the collar and holds both the “hot” and “cold” smoke tubes. In addition to welding this tubing joint (which I do NOT recommend – I’m not intending to use this design in future revisions, because of possible corrosion issues with the weld), I also had to tap a 2″ hole in the 304 stainless collar. On my first try, I completely destroyed the tap (Picture 3), a screw-up which I have yet to beat in terms of potential-cost-of-damage. Thankfully, the head machinist at Swarthmore was understanding, and I was able to have the tap reground by a local tap-and-die manufacturer for a fraction of the cost of a new tap.
Possibly the most enjoyable machining task in this whole project was the bowl. I elected to make the bowl out of grey iron primarily because I knew that iron was food-safe, even under high heat. It turns out that iron is also a pleasure to machine: it cuts easily, and comes off as a granular powder (the machinist described it as “instant coffee”). Once the bowl was finished, I seasoned it like a cast-iron pan, creating a hard, corrosion-resistant coating.
Thus far, the hookah has been wildly successful, and has been a fixture among my friends since. It is by no means perfect, however, and in all my copious free time, I am intending to someday create version 2.0 of this hookah. I’ve got a long list of improvements for the second iteration, including:
- No welding: Although the welds in this project have remained airtight thus far, they are extremely rough. Furthermore, the metallurgical changes caused by the welding (I had neither the right tools nor training to be welding stainless steel) have led to mild corrosion at the weld – not ideal for a hookah that’s supposed to be as inert and “clean” as possible. Future revisions will use press-fit or threaded components instead of welding.
- Bowl redesign: Although the cast iron bowl fits the modularity and non-reactivity requirements of this project, its thermal mass is too high – it’s extremely slow to heat up, and when it does, is prone to burning the tobacco. In future revisions, I would either replace the cast iron with a ceramic bowl, or make it significantly thinner.
- Reduction of weight: One of the greatest problems with this hookah is its significant weight and height – it’s hard to carry around, and tends to be top-heavy and tip-prone. Future revisions will be both lighter and have a lower center of gravity.