Gosh, after reading your post, James, I'm so glad I bought my sample roaster new
I've heard of WD-40 (the spray stuff) being used to dissolve most any gummy, greasy, mess. It might work for your purpose but since it almost certainly is NOT food safe, you'd need to be able to wash it off with some sort of detergent or soap and water to get off all traces. I have no experiences with using WD-40 this way, however.
As to your long range plans, getting a thermocouple inside the roasting drum will be a challenge, and once you get it in there you don't want it to be chewed up by the stirring vanes. I ordered a custom ensheathed probe from Omega, and it took me about a year to figure out how to install it:
Easier than this, and perhaps more practical in a multi drum setup like you have, would be to make a simple stand with an ensheathed straight thermocouple that you can position during each roast. Although somewhat less accurate and repeatable than my permanently mounted probe, I found this sort of arrangement quite useful and perhaps 85% as reliable as permanent probe I'm now using:
The above is an early picture from eons ago; I now use my Fluke for temperature monitoring when roasting, which adds to the accuracy a bit as well.
I have a gauge mounted in-line on the gas flow. Due to the fact that the burner adjustment valve is on the roaster side of the gas flow path, what I see is actually "backflow," and gives an inverse reading to what a gauge mounted after the adjustment valve would show. Nonetheless, since it is repeatable, it is hugely useful in roasting. I would not know where to start (flame height wise) if all I had to look at was the flame, without getting some indication of how much gas is actually flowing.
Good luck James and let us know how this works out.
ken
EDIT: Out of curiosity, I examined my sample roaster carefully with attention to the inside of the drum, using a bright flashlight. The roaster is clean, inside and out, aside from minimal chaff and a little of the high temperature food safe grease I use through the grease zerks (and where that grease ends up). The inside of the drum is clean. I have owned the drum for 4+ years and probably put around 300lbs (or more) of green coffee through it. Since sample roasters are not generally used for production (as I use mine), that may represent a fairly large amount of use. In any event, it is a little hard for me to figure out how your roaster could have gotten into the condition it is in, unless the people using it never made any attempts at cleaning it during its prior service life.
the past.
