Probing Butane pre-order

[threechrome]

Probe Question
I wanted to order extra probes for all digital/ phidget/ variac set up..would I order extra of all three ET, BT and MET?
Regarding Butane
I was thinking about going the butane route with ir burner just to have the option of indoor or outdoor. Most of the time roasting will be spent in the garage (seperate from house) venting out the door with a solid drum. Is the main reason for getting propane to provide more number of roast for less money? Does propane burn hotter and better with a solid drum?
Is there more of a risk damaging huky with butane?
Thanks in advance for any help.

[edtbjon]

You should specify in your order that all three probes should be "digital" (i.e ThermoCouplers). It's not a bad idea to order a spare TC or two, as it's just about the only thing on the Huky that has any kind of wear to it.
Propane is of course much more economical, but the IR burner is very fuel efficient and uses very little gas. Without having done any math, with propane, the cost for gas per roast is well below one dollar, maybe even well below 50 cents. (This is dependent on the size of the propane bottle. Larger bottle gives better economy.) Even if the small butane bottles cost more, you will still be well below the dollar per roast.
If you order the IR burner setup for butane, it will be working in the same way as the propane setup, at the same temp ranges etc.

[threechrome]

Thanks edtbjon!
A few more questions to throw out there...
Ah ok...so then are all three "digital" probes the same type?  just in different places? And when ordering after specifying all digital ET, BT, MET, if I wanted two extra probes would I just ask for "two extra digital ET"? OR  "one extra digital BT and  one extra digital ET"?

[edtbjon]

The probes are called ThermoCouplers, so extra ones are called just that (or TCs). I'd write "2 extra (spare) Thermcouple". They are $18 per piece.

[edtbjon]

Well, some numbers on propane usage. I did some 5 roasts today, including a 20 minute warmup (@ 1.0kPa). I charge very low, so I can (and have to ) hit the burner very hard in the first phase of the roast. So, the numbers... I used some 120 grams of propane for all the 5 roasts including the warmup. (Even though there may be somewhat different numbers with butane, it should be in the same ballpark.)
(In Sweden) Propane costs 'tween $3 and $6 per kilo when refilled. All in all I spent less than 50 cents of gas for this roasting session. .)