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Started building this yesterday and finished today at around noon. However, Ive spent quiet a few hours in planing the execution to suit my particular application. As you can see, Ive used a terracotta pot as the centre piece for good thermal retention. Underneath I had fabricated a sub-frame to house the agitator engine, which happens to be an automotive power window motor. Power supply comes from a battery charger thats been flicked to the 6 volt setting to reduce agitation speed. The hard part for me was do I put the motor inside the pot to drive the agitator, or do I make an extension to have the motor outside to isolate it from the harsh heat! The second option was my choice of path, but that meant it needed a long shaft and a means to support the shafts ends to prevent sideways thrust.
Luckily I had an old XF Falcon distributor which I was able to locate it inside the pot. The stainless steel bowl sits on top of the distributor and is fastened to it for stability. One headache was making a coupling to link the motor to the distributor drive - after about an hour cursing I made a coupling that allowed a little bit of freeplay between the joints to compensate for any possible misalignment - in doing that I minimised any extra loading to the motor which would have otherwise caused an increased current draw. Fully loaded with 1/2 a kilo of beans the motor draws around 2 amps @ 6 volts.
Even though I have a temp probe I did not bother to use it on the maiden run as I just wanted get it done. Anyway, the ovens thermostat was working as it should, cycling the heating lamp on and off at around 210/220c.
First crack was around 8 mins, and the 2nd was around 12. The end result is pretty good, but noticed some beans started going dark rather quickly. Thanks to Andys "starter pack" I roasted the 4 different origin beans, but I suspect that was the reason the roasting was not as even I hope for, but it is what I kind of expected as the beans varied greatly in size. Next time Ill separate the batches to roast them individually.
The turbo oven kind of scares me with its UFO bright light effect, and I was worried about blowing up something. But in the end everything went very well. I drilled holes into the bowl for some chaff removal, but the chaff that was flying around due to the air circulation was so big that you cannot drill big enough holes to eliminate all of the it without loosing many of the beans.
When the roasting was done I initially had just the fan of the oven running but was not sure if it was good enough to cool the beans. So I tossed them into the colander and shook them to cool off. Next time Ill turn on the compressor to blow the heat away from them quickly.
And yes to your question, I did sample them with my Lelit and was pleasantly surprised. Very smooth tasting with a light coloured crema (not dark as many would prefer). The beans are now in vented bags. Thanks to all for contributing to this site and especially to Andy for the quick delivery and for the rustic looking calico bag to hold the green beans.
Luckily I had an old XF Falcon distributor which I was able to locate it inside the pot. The stainless steel bowl sits on top of the distributor and is fastened to it for stability. One headache was making a coupling to link the motor to the distributor drive - after about an hour cursing I made a coupling that allowed a little bit of freeplay between the joints to compensate for any possible misalignment - in doing that I minimised any extra loading to the motor which would have otherwise caused an increased current draw. Fully loaded with 1/2 a kilo of beans the motor draws around 2 amps @ 6 volts.
Even though I have a temp probe I did not bother to use it on the maiden run as I just wanted get it done. Anyway, the ovens thermostat was working as it should, cycling the heating lamp on and off at around 210/220c.
First crack was around 8 mins, and the 2nd was around 12. The end result is pretty good, but noticed some beans started going dark rather quickly. Thanks to Andys "starter pack" I roasted the 4 different origin beans, but I suspect that was the reason the roasting was not as even I hope for, but it is what I kind of expected as the beans varied greatly in size. Next time Ill separate the batches to roast them individually.
The turbo oven kind of scares me with its UFO bright light effect, and I was worried about blowing up something. But in the end everything went very well. I drilled holes into the bowl for some chaff removal, but the chaff that was flying around due to the air circulation was so big that you cannot drill big enough holes to eliminate all of the it without loosing many of the beans.
When the roasting was done I initially had just the fan of the oven running but was not sure if it was good enough to cool the beans. So I tossed them into the colander and shook them to cool off. Next time Ill turn on the compressor to blow the heat away from them quickly.
And yes to your question, I did sample them with my Lelit and was pleasantly surprised. Very smooth tasting with a light coloured crema (not dark as many would prefer). The beans are now in vented bags. Thanks to all for contributing to this site and especially to Andy for the quick delivery and for the rustic looking calico bag to hold the green beans.
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