Tuesday, January 5, 2016

Cabin Heater Blog Post Part 2

After building the prototype (see blog post Max Makes A Heater), and designing the stove on Solid Works, I put in the order with Kammetal for ten, 22 gauge, 304 stainless steel, mill finish stoves with the hope that I wasn’t wasting well over 1000 dollars at a time when the boat could use the money.

The parts were ready a little over a month later.  I rushed over to Kametal excited and nervous to see if the parts I had dreamt up would actually fit together, or if I had just purchased the world’s most expensive pile of scrap metal.  3D modeling may seem like the end-all be-all of product design, but the truth is that it’s a tool, and like any other tool, it requires skill and patients to master.  The best advice I can give is to never assume anything.  Check and recheck everything, buy parts that you plan to incorporate into your design, look at them, feel them, measure them, whatever you have to do to uncover the next problem with your model.  If you can’t find any problems, it means your not looking hard enough.

I assembled the first Kufner Stove on the kitchen table as soon as I got home.  The parts slipped together with such precision, I was jumping up and down.  She had the perfect proportions and looked elegant yet modern with a dull reflective finish that expressed both modesty and reliability, or at least that was my first reaction.  As anyone who has ever built anything knows, after the initial sense of accomplishment, you begin analyzing your creation over and over again for every possible fault.  I can only imagine how many inventors kept their inventions from the world simply because they couldn’t help but fix that one last problem they had discovered.

·       I designed the fan control switch board for a potentiometer.  I had assumed the potentiometer would have enough resistance to completely shut the fan off, but I was wrong.  I eventually tracked down a SPST Rheostat that would do the job and fit nicely into my custom bracket.  A Rheostat is essentially a potentiometer meets rotary switch combo.
·       While I had designed the heater to use standard parts and as few different parts as possible, I hadn’t realized how important the sequence of installation was.  The result is a difficult to assemble product where its easy to skip a step and end up with no access complete it later on.
·       I designed the bracket which supports the burner to long resulting in the burner hanging too low.  The flower pot wasn’t heating up and the heater was under performing.  I eventually had to ask Kametal to make me a new bracket.

·       The propane burner I designed for is a high pressure burner whereas boats typically use a low pressure propane system.  This is a huge problem that I have yet to solve.  The stove still works with a kerosene burner, but most people want propane.  Unfortunately, I think the only solution will be to find a different burner.  This problem was actually discovered by the first person to purchase a Kufner Stove on Ebay.  I am fortunate that he is a really nice guy and has been sending me updates on modifications/installation.

That’s it for now, at least for the problems worth mentioning.  I don’t regret building my stove.  In fact I still think it as beautiful as the first day I saw it.  I’m sure my affection towards it will grow as I tinker with it at sea, or as it keeps us warm in the southern ocean.  I don’t think it will ever be a money maker, but that doesn’t matter.  The Kufner stoves are out there and its because of me.

My stove is not free of faults, in fact it has many, and those that I have discovered have kept me from selling them in any great numbers.  To be fair, Laura and I are busy preparing the circumnavigation of an American continent, which has nudged the Kufner stove to the back burner of my mind.  Regardless, in the interest of full disclosure and the informative nature of this blog, I am prepared to share all the problems I have found no matter how embarrassing they may be.