Very nice movie, a little hard to hear what the main person, Harry, was saying mainly because of the broad dialect (gotländska, I presume) but also from the lower quality sound. I remember those video cassette recorders back then, mid eighties. My grandpa had one 
A KISS setup as it should be, no bells and whistles and no overcomplicating contraptions. I enjoyed that movie a lot, thanks Göran 
I loved the turpentine level checker, so easy. And the turpentine separator too, lots of ideas in this one.
The one thing missing was leading the cooled gasses back to the fire, perhaps they felt it to be too much uncertainty regarding temperature when doing it that way. But a separate charcoal unit using those gasses as a supplement in the beginning would work just fine.
