Bob, I believe that information is a magical thing. just sprinkle a little bit around and you never know what might happen. So for those that might have any interest in temperature control, including myself. I googled the controller you mentioned. The top link on the list lead to this.
http://www.pexsupply.com/Ranco-ETC-...t-11627000-p?gclid=CO7Oq4Pt7a4CFasERQodeAIGHw
Even at $50 (not including shipping) that costs as much as 5 hot water heater thermostats. Given that I have two years experience with several hot water heater thermostats I would say it is a great deal. It would take a bit of work to even get a water heater stat to 170 degrees. I know they say they go as high as 190 but keep in mind that is sensing the temperature through the metal of the tank. The temperature of the surface the stat is touching is nowhere near 190. sensing the temp from air contact I find it hard to get much above 100 degrees. Even then it is not very accurate control.
Thanks for the suggestion. I have all summer to work out the details of a home built flue curing chamber but I fully expect to take it on this year. I don't think it has to be much more complicated than a kiln. The temperature is higher and needs to be more accurately controlled and adjustable. air movement is more critical. And humidity control is much more of an issue. Heat may require significanly more power. I am looking at it is basically the same amount of energy will have to be used in a shorter period of time.
I have a lot of ideas and some experience that gives me a good chance that those ideas are at least in the ball park. BTu here are the main issues is see with designing a flue curing chamber.
1. reliable accurate control of temperature.
2. enough power to supply the heat requirements. Not only are higher temperatures necessary but the system must have the ability to increase the temperature in a specific time frame. For example increasing the temperature by 2 degrees per hour over a several hour period. This may not be asking a lot when going from 100 to 102 degrees in one hour. but going from 158 to 160 in one hour may prove to be a whole different challenge.
3. adequate air movement through the chamber. I see this as possibly the most difficult to get right. From what I can tell tobacco is packed in a flue curing chamber far more densely than in other forms of curing. Other curing methods rely mainly on the natural movement of air while flue curing relies on t he air pretty much being forced through the leaves.
4. Removing moisture from the chamber while not loosing heat excessively. The much higher temperatures required are goign to make this a much more costly device to operate. anything that can be done to minimize that power usage will be significant. Two things I see that can reduce this power requirment. a. insulation and air tightness. b. retaining that air tightness even in regard to the removal of excess water. This may sem difficult at first thought. But actually the method of removing water from a chamber and retaining an air tight seal is very simple and has been known for a very long time. It is called a P-Trap. every drain in your house has one and it keeps sewer gases from coming back into your house. that is why your bathroom does not smell like an outhouse. The only other issue is how to get the moisture int eh air into a pan so it will drain out through a line with a P-Trap in it. I have some ideas on how to do it but will have to experiment to get it right if it will work at all. So far I am thinking of some sort of condenser where the moist hot air will contact a cool surfae. the mositure will condense on this surface and run down to a pan and out a drain fitted with a P-Trap. a network of copper pipe with cold water being pumped through it. this condenser would be able to run only when humidity readings indicate it is needed.
that is just a brief overview of where my thinking is going on this.
One of my first thoughts when I saw the containers the other day was that where I work they throw away a to of metal frame work. The discouraging thing since then is that I have watched an almost non ending pile of such frame work get tossed out since then. all of it far to heavy for me to able able to get. One huge 8 foot long 4 to 5 foot tall and 4 foot deep frame on wheels was setting along side the dumpster two days ago. If I had a trailor and the space I would have taken it in a heart beat. I don't know yet just how I want to try and construct this. I will most likely start with a very small chamber of say 8 cubic feet of space in order to work out the details in proper air movement and humidity reduction etc. then scale up this design to the full size chamber It think I will end up needing.
To may projects right now. my brain is getting stretched to thin. our electric fence. drip system and the lat items for my beehives all arrived on the same day yesterday. That kicked me into the next phase of three projects for today alone. It's going to be a long hard spring.
The best controller I have seen is the ranco etc-111000-000 it can be purchased prewired for easy installation expect to pay about $75.00 for it. It is easy to program and use. It has a max temp range of 220 f making it quite suitable for flue curing
bob