Condenser for a 2 1/2" Boka

[harrance]

Finally decided to have a go at building a Boka'. I have been given a lovely 2m length of 2 1/2" copper pipe, which brings
me to my first problem, dimensions and material for the condenser.

In my research I have seen many designs for 2" column with double coils of 1/4" pipe and 3" using 3/8" pipe. With these combinations the coils take up half the cross sectional area of their column.
For my 2 1/2" column I am sure 3/8" pipe will be too thick to wind a coil properly. Then I am worried the 1/4" will be too thin, that is, not filling enough cross sectional area to work effectively.
I have been thinking about winding 1/4" tube at a diameter suitable for 2 1/2" and either putting some scrubber in the now larger empty core or maybe making a type of cold finger out of a loop of 1/4" to fit down the center of the coil.

I would appreciate any advice on this subject.

Thanks, Harrance.

[bt1]

Hello,

Yeh a cold finger with 3/4" inner tube would be a nice choice, it's well over for what a Boka would need but a little spare capacity never hurt.

Another option used to use on Hybrid pots (pots with coils) is to wind normally producing a slightly wider gap between inner and outer winds. Then thread SS scrubbies between the two. Periodically pull a small few threads through the outer coil winds as well assists to hold it in place.

The surface contact with both coils effectively cooling the stainless scrubby filler giving you a larger volume of cooling space. The vapour will flow through the scrubby and condense.. it's a efficiency improvement over a std. twin wound helix coil.

bt1