Kilns and Saunas

Kilns and Saunas

You’ve probably heard that I’ve spent a lot of time in and around the saunas. But another hot spot I’ve spent a lot of time around is kilns. Specifically, foundry kilns and ceramic kilns. Unsurprisingly, there is a strong relationship between the two, as they both involve getting things hot. In the lost wax casting process, investment or ceramic shell molds are heated to roughly 1500° F. The extreme heat burns off the wax original, and thus, the lost wax of lost wax casting. This can take hours or even days depending on the mold type and size. A ceramic kiln can get much hotter, up to 3000° F. That is hot enough to melt steel and many other metals.

Rob at a bronze pour.

I learned how to do bronze casting in art school. It is an ancient process, and my classmates and I did it pretty much the same way that it was done thousands of years ago. We learned to determine how hot things were by using our senses. All objects emit radiation when heated but at about 1100-1300° radiation becomes visible. Peering into a hot kiln (safety glasses strongly suggested) is like looking at another world, perhaps on some gaseous alien planet.
The blast of heat through the spy-hole is like a ray gun. Solid objects become transparent. Heat and light become one; the heated molds don’t reflect light but emit light. We rarely used pyrometers (hi-temp thermometers), and when we did, it was only to affirm what our senses were telling us. We recorded the smells of things burning off. When the smells were gone, the molds were clean and ready to accept the molten bronze.

When a kiln is loaded, there is always discussion about the hot spots—certain delicate molds need to avoid the highest heat while larger molds might need it more. There is always conjecture about how the heat circulates; a whole aspect of kiln building is dedicated to controlling the flow of heat within the kiln. Some of this conjecture is borne out in the results of a firing—whether things fire correctly or not. Ceramicists use cones: small tapering forms that bend at specific temperatures. After a firing, these devices will give a true telling of how the firing went. But despite the science, there is still a lot of mystery and art to the process, so much so that a firing of a large kiln can take on a ritualistic feeling. Staying up late to tend the kiln (as is done with wood fired and other non automated kilns), drinking beer, and heating up pizza on its surface add to the aura.

Thinking of all of this casting lore makes me think of sauna. Both processes have been done pretty much the same way for millennia, involving community and an aura of ritual. Both focus on fire and heat, and even as well studied and commonly practiced as they both are, there is still a bit of mystery involved in each process.

A kiln is like a sauna on steroids. The heat is so amplified that its flow and effects are unmistakable. Observing a kiln is a lesson in thermodynamics. In the sauna building culture, there is a lot of banter about how to best heat, insulate, and vent a sauna. Yet, all of it is conjecture, based on theory, until one sits in a sauna and feels the heat radiating off the rocks and the wave of löyly hitting the sensitive tips of your ears.

When I design a sauna, I draw from my years of kiln experience. I think of the heat as a visceral substance, almost visible, as in a kiln. I relish using my senses to discern quality rather than depending on technology. Even if the sauna is electric with a digital control panel, I rely on feeling, not the number on the display. I imagine the flow of heat like the way it flows in a kiln. My foundry experience has informed my understanding of sauna in ways that are hard to describe, but suffice it to say that I have always been drawn to fire and to the mysteries that it holds.

Sauna Pricing in Covid Times

COVID-19 sure has made life strange and difficult for all of us. Patterns of living have upended, and new norms have emerged that will probably stay with us. One pattern that became very clear was that many people have decided to make their homes more livable, especially when it comes to outdoor spaces. Fortunately for me, this includes home saunas, which have seen a enormous spike in demand, which I am trying to keep up with. But, there has also been a huge increase in demand for materials associated with these types of projects, causing me delays and headaches. Like the toilet paper that disappeared early in the pandemic, framing lumber, cedar, and pressure-treated decking have all but vanished in some stores. Not only are people buying more for their home improvement projects, but the triple whammy of last years wild fires, COVID taking out some of the workforce, and tariffs on Canadian lumber has caused major shortfalls and substantial price increases in building supplies. Yesterday, I bought a single sheet of OSB—oriented strand board—the most ubiquitous of building materials, and the sheathing on virtually every house. It cost me over $27. Twenty dollars more than what I paid eighteen months ago. Everything else, from 2x4s to steel plates have doubled. 

The contracting business depends on giving a solid price well ahead of time so the buyer can plan and budget. I’m working on projects I bid six months ago at prices I thought I could expect to pay when I got to the checkout. How can I give quotes when the prices are going up like that? Often, I have to eat those unexpected cost increases. Maybe the prices will fall, but like wearing masks in grocery stores, I think we have hit a new norm.

I can’t absorb all this pricing mayhem, so I have to pass some of it on to my customers. If you are doing a DIY project and using someone else’s book written years ago, be sure to check prices; the big box stores do a pretty good job of posting it all online. And when you ask me how much something costs, remember that cost, like time, is a fleeting thing.

The most important thing to remember is: how much is a sauna worth to you? It is measured not in dollars but in real value added to the quality of your life. In other words, priceless.


With over 30 years of experience working in the building trade, Rob readily dispenses his knowledge to clients, a clear, professional communication style. If you need in-depth information on how to build your own sauna or need drawings/plans, whether you are a builder, DIY builder, or architectural firm, I offer plans and consults. BOOK A CONSULT HERE >

Candle windows

Candle windows hark back to my time at Podunk, where the light in the sauna came from a bare bulb in a porcelain fixture outside a little square window into the dressing room. A sauna is too hot for a standard light fixture, so this arrangement made sense. Later, after I started building saunas, I learned that this was a more modern incarnation of the original candle window, which was literally a window into the dressing room with a shelf for a candle to sit on. These windows are common in Finland in freestanding saunas away from the house. The candle window allows a special, spiritual, summoning light into grace the sauna. Especially on those dark winter nights.

In the sauna tradition, we slow down. The flickering candle-light, seen from the bench in the sauna, lures you to relaxation and reflection. Life and relativity. Could there be a more tranquil way to release the stresses of the day?

Although it is this quality of the light that is so important, the candle window is totally pragmatic in a very Finnish way. A candle in the sauna room would melt even if not lit, so this setup was an obvious solution to the problem of lighting the dark interior of the hot room. Despite its pragmatic origins, I find it is also a chance for a little expressive design: it can be round or square, arched or colored. It can have an organic flare to it. Now, with cheap, battery-operated, multi-colored LED lights and even fake candles that look real, the light can be more than a simple bulb on a pull-chain porcelain fixture and be safe. Even if the sauna has built-in electric lighting, the candle window can be a signature element, one that distinguishes a personalized custom sauna from a generic kit.

Candle window design by Rob Licht

It’s in the details.

Finnish pragmatic design inspiration comes from using what is available at hand and letting that material influence your design. There are many places to incorporate little details and personal touches: stick hardware towel pegs, stone-faced walls with stones from your backyard, thresholds of locally cut locust, round windows, etc. Think of decorative elements you can hang above the mantle. In my sauna building plans (which can be purchased and download), there is more about windows: framing information and tips on using windows safely in mobile saunas.

Wood-burning sauna with a simple candle window to dressing room.
Wood-burning sauna with candle window to dressing room.

Here is a collection of the candle window designs and builds I’ve used over the years in and around the Finger Lakes and throughout New York State.