Building a hot tub
"Tub Talk - with Dan Jung ? Owner www.cedartubs.com / Hot tub enthusiast"
What is Required to to make a hot tub?
A hot tub is an architecture marvel that draws people's focus. A hot tub's pureness and simplicity in design demands attention. However, the simplicity one finds in a hot tub is only the result of years of R & D and a deep understanding of the principles of Cooperage.
I often get customers who use our product and our web site as their home work in anticipation of building their own hot tub. Sure, they are crafty and wood is easily accessible so maybe they will just build their own! In fact, "build a hot tub" is one of the most often searched fraises under "hot tubs". I always give people the advice they seek and wish them luck on their endeavor. The reality is the amount of work that goes into building a commercial grade hot tub requires two very important ingredients:
1) Top quality material
We use only Clear Grade Western Red Cedar with a "2 Clear or Better" rating, this is absolutely critical in designing a hot tub that will last. All our wood is hand selected and milled with a specific grain pattern to obtain natural circular curve overtime. To give you an idea of the cost factor, typical retail cedar that you will find at your local lumber shop is 5-grades less than the grade we select and is reflected in its cheaper cost. In other words there is simply no substitute for Western Red Cedar!
Other areas of quality are found in our sturdy engineered seats that fit perfectly with a unique dual height for comfort and ease of entry.
Our choice of digital spa packs is another significant statement towards quality. Digital packs cost significantly more but the resulting product is much better. Temperature accuracies of +/- degree, on board diagnosis, and ease of use are just some of the added benefits.
Our use of only stainless steel makes a huge difference; Stainless steel is 5-6 times the price of regular steel but it is required in order to have a tub that will maintain its appearance and not rust or deteriorate the wood. Through the years we have tried all sorts of methods and materials including powder coating the band. In the end, only stainless steel will truly work. Our bands are 2" wide resulting in even pressure distribution when tightening.
2) Engineering design
I often tell people of the preciseness needed to obtain an exact circumference of a complete circular of the magnitude of 6'. Remember your school days of "2 * pi * radius". Let's use the example of a 6' tub and change the radius. Imagine a radius change of only 1/32" close to that of a human finger nail in thickness, the results would end up with a gap in the staves nearing a ¼". This would certainly not be acceptable in holding water.
The other area we need to apply in our formula is the swell ratio. All wood including cedar have vertical swell ratio and a horizontal swell ratio. These are never the same. Each wood swell ratio is also a factor of the moisture content and varies across species. Without going into further details, these are only some variables that play a very important role in producing a water tight seal. This we call our "Cadbury Secret"!
We use a very precise computer-controlled dado machine that has an X, Y, and Z 3-D axis. This allows us to perfectly match the radius of the dado cuts on the staves with that of the floor. Most other manufacturers simply use a straight chord cut which only touches the floor in one specific spot making it susceptible to leaks.
All our components are computer modeled before they go into production. The Romans may have called this cheating when it comes to Cooperage. However, it certainly produces a barrel that even the Roman Emperor "Caesar" would have been proud of and would most certainly enjoyed soaking in.
Some people call it science others call it an art. Either way the ability to design a tub to hold 500 + gallons of water is not an easy task. To those who are brave enough to try their own, Good Luck!