Homeroasters - Home Roasting Coffee Community » BUILDING A ROASTER » Turbo Oven Roasters
Who is here? 1 guest(s)
 Print Thread
successful build of my version on a scto
jinx
Top  #1 Print Post
Posted on 02/29/2012 10:43 AM
So, I just finished my build, I have one roast batch under my belt. I thought I would share the info because I know I read alot of other folks' stories about their builds before I tackled mine.

I bought the stir crazy from target. I got the supentown SO2000 from walmart, shipped to the store for pickup. I bought a 12v strong geared motor from a science hobby wesite, 50rpm, and used a laptop transformer brick as a power supply. I had to hack into the bottom of the stir crazy to remove the weak motor. I then cut a rib or two of plastic to seat my motor's flange on the base, it screwed in nice and tight. I elongated the axle with a few hardware bits, so it stuck out high enough out of the pan of the stir crazy.
I added a wooden box to the bottom of the SC, to make room for the motor, and to raise the height of it and inrease stability. I drilled screws right through the plastic base, there are 4 circular feet pads on the inside.
I then went about fabricating an agitator. The first go around was too elaborate, it was a propeller shape in thin aluminum that wasn't rigid enough. I removed it and went to stiff wire, wrapping it around the axle and bending it in place. After testing it with beans, I added a hole for my thermocouple probe, under the agitator, through the side wall of the SC, and the pan.
I added a 2 inch wide, thin flat bar of aluminum to the perimeter of the pan by bending it into a circle. I left an exit chute so chaff that spins counter clockwise would exit out, that's an important tip that works well. I keep the chute open by drilling a hole in the aluminum bar, threading it, and screwing in a bolt. Not pretty, but dead simple.
I added a silicon tube to the top of the rim by slitting it. I then did my first batch, following the lead from previous users.
I ramped up slowly, got to 350 in 8 minutes, turned up the head a bit, then more, saw a good rise in temps, so I backed off the heat some. The beans went to 453 in 16 min.
I cool them off in a styrofoam beer cooler box from 7-11. I put a hole in the top, inserted a bucket that has a screen as a bottom, and suck air through a hole in the side of the cooler and utilizing a 5 gallon bucked sized shop vac I already owned. Beans cool in 20 seconds. I taped everywhere in and around the box, it can't be beat for price and use.
I drank the coffee this am, I was quite pleased. Better than the west bend popper that I was using before. I put out a sample of 20 beans from this and the air popper on the table last night and compared. The SCTO beans and more homogenous, slightly deeper, and have a more uniform surface texture to them. Simply yum.
My next roast will incorporate the the following tweaks - heat the unit to 200f prior to dropping in the beans. Ramp up dry time should be to about 8-9 minutes, then over the threshold of 1c, and slower to finish at 450 ish, depending on the bean and mood.
I need to increase the size of my funnel for dropping hot beans into the cooler, as the SC pan is wide.
Other than that, this method is really simple. I like to use a infrared laser to get fast temp readings of my beans, as this measures surface temp and not ambient air temp like thermocouples do. But, I can't seem to do that with the glass lid in place. I need a slider window in the lid to open and shut.

I use a pid silvia and a baratza preciso grinder, my beans are sweet marias, and I am looking forward to more experimentation.

I have very few pics at this point, and they look alot like the other SCTO out there.
 
jinx
Top  #2 Print Post
Posted on 02/29/2012 10:49 AM
I forgot to mention that the rubber tube on the rim of the aluminum melted badly during the first roast. It must not be true silicone. I am now going to source a substitute material. I am thinking heat shield tape, auto exhaust wrap, fiberglass tape, a strip of fire blanket, hell, even an oven mitt or rubber trivet would do in a pinch.
anyone have an idea?
 
JackH
Top  #3 Print Post
Posted on 02/29/2012 3:32 PM
Hello and welcome! Looks like you have done a lot of work to your roaster and I would like to see photos when you get a chance.

Try US Plastics for silicon tubing.

Here is the link: http://www.usplas...;catid=799

Lots of size choices can't remember the size I used. Good to 500F.

--Jack
 
Koffee Kosmo
Top  #4 Print Post
Posted on 02/29/2012 4:22 PM
Yes look for high temp silicone tubing

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
jkoll42
Top  #5 Print Post
Posted on 03/01/2012 7:28 AM
mcmaster.com is always a great source also
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
jinx
Top  #6 Print Post
Posted on 03/01/2012 9:25 AM
thanks for the links, Im all over them.
 
jedovaty
Top  #7 Print Post
Posted on 03/01/2012 10:05 AM
I got mine off amazon, look for high temp food or medical grade.
 
Jump to Forum: