Hello,
I'm the guy who published the Whizbang chicken scalder plan book and I appreciate this discussion and the great pictures of jaku's homemade scalder. I just found my way here from a Google search. I'm in the process of preparing to reprint the plan book and was looking for feedback so I can update the new printing. I published the book in 2005. The feedback I've gotten over the years has been positive. The Whizbang scalder
automatically maintains temperature remarkably well, for as long as you are processing, and that is the primary benefit. Besides that, the insulated water heater tank keeps the heat in very well. A little propane goes a long way with an insulated tank. This lack of tank insulation is one drawback to the ready-made scalders on the market. I've been told that they take a lot of fuel to maintain optimum temperature. As for the auto dunker, most people don't make their scalder with it because of the extra cost. I make it clear in the book that the dunker is an option and it is possible to make a manual dunker.
The Whizbang scalder itself is something of a luxury for anyone who raises "backyard" chickens but it's a godsend if you raise a lot of birds to sell. Same with the auto dunker. I will say that one person told me the skate wheel on their auto dunker wore out and they substituted an idler pulley. That was his only constructive feedback, besides pointing out that it is important to keep the baffle in the water heater chimney, but the book makes that clear.
As for my own scalder, the one I developed before publishing the book, I use it every year and it continues to do the job very nicely. I simply roll it out of storage, fill it with water and turn it on. It heats up faster than an electric scalder and maintains temperature with no help from me. If you are interested in seeing more pictures of the Whizbang scalder, I invite you to read my online essay about it at this link:
http://whizbangplucker.blogspot.com/2010/04/introducing-my-deluxe-whizbang-chicken.html
Also, for those of you who scald your birds with a turkey fryer pot or galvanized can, you will find a link in that essay to another essay in which I fully explain how to get the
perfect scald on your birds,
every time, no matter what kind of scalding equipment you use.
Thanks again for the great discussion and inspiring pictures.
Best Whizbang wishes,
Herrick Kimball