Here is a overview of my first roaster
It was a proof of concept and it has done hundreds of roasts, most of them over a pound s:1s:2
I started with a Bread Machine from a thrift store, for about 3 bucks. They vary in price all the way up to $20.. but I just get the inexpensive ones.
This is what I started with:
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I chose this one because it has a strong locking mechanism to hold the bowl to the bread machine. s:2
Here is the inside of the bowl:
It has done some roasts
You can see how I cut the bottom of the 8 qt mixing bowl out and replaced it with the bottom from the bread machine loaf holder.s:4
This keeps everything aligned well.
The thermocouple threads down through the ss tube on the left top.
You can see the mods I did to the paddle.
Unfortunately I trusted Hi Temp RTV to hold it together.
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It is safe enough, but it failed in about 6 months. s:7 s:6
I had to replace it with screws. A better choice.
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It mixes better when there is less deflection also.
The hole that the shaft goes through is too large, s:8s:8
so I had to make a washer to fill in the gap. c:1
The bread machine in this version uses the original outer sheet metal and controller.
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The bowl protruded out the top so I had to add some flashing to hold the insulation in.
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The Galloping Gourmet convection oven does a good job. s:2
I had to take it out of it's glass lid and mount it in pot lid that fit the mixing bowl nicely.
Here is a pic of it mixing one pound:
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and another with two pounds of green coffee beans:
Even though it appears that it could roast more than a pound, it has difficulty because the beans expand, It needs a larger bowl
and a lot of heat is lost that could be retained with better iinsulation. s:8s:8
My next rendition will address these issues
First real problem with this roaster this week
The screws pulled through the aluminum holding the clamp section onto the ss bowl!
Second picture from the top s:6
It needed taking off, replacing the screws with larger ones, and filing them down so there was no drag. Also upgraded the insulation.
This makes a good reason to mount the aluminum outside of the SS bowl, like the new version will be. Only the stirrer on the inside.
It works fine again.
Need to keep it running while building the new one. Almost have all the parts now
Edited by Dan on 06/17/2007 05:37
Another breakdown today
What failed today was the Galloping Gourmet! Well, the micro switch for the handle interlock died.
Also the wires going to the timer were over worked and about to fall apart.
By passed both and it works fine again. s:2
In the year I have been using it it has done well for an experiment, and I learned a lot about how to do the next one.
Already had planned to bypass the timer, micro switch and thermostat.
It is interesting to know that they don't last forever.s:3
The original bread machine is still strong.s:2
Well over a hundred roasts, and it even stays out in the rain (Well, it hardly ever rains here in LHC)
Now I have the chamber mounted with larger bolts, and upgraded the insulation.
No problem at all doing back to back 625 gr roasts.
Edited by peterz on 03/01/2006 17:55
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When I took it apart it was covered throughout with Roastium s:7 s:6
The wires that were left had all but evaporated, and the heater element wires..
well you'll see c:2
Here is the top of the chamber above the chamber where the heater coil is mounted:
The power comes in here goes up to where the fan is, and comes back through those holes to run the heater.
It is supposed to be white, but the brown finish is now baked on.
The fan is supposed to be shiny aluminum.s:7
That fan is on the same shaft as the recirculating fan, and it's job is to keep this chamber COOL so the wires don't cook.
The next picture is of some of the wires and the spade lugs mounted on the heating element.
This is the floor of the last picture. The heater is bolted to this plate.
Those connectors have oxidized away so they need to be replaced, and the silicon shield has disintegrated.
I plan to drill holes and attach to the element with screws instead of push on.
Next is a pic of the business end of the turbo oven.
That hole is where the shaft comes through to mount the recirculating fan.
Surrounding it is a field of Roastium, and then is the heater coil.
You soon get to the end of the TO which is secured into a pot lid so it will fit the
SS mixing bowl.
Lots of Roastium here, burned on black and thick.
The three stand offs support the grill that goes over the heater.
Next is a pic of a new 1200 W element I just removed from another TO
It looks like this element and it's mounting plate:
would easily mount in front of the fan with a little sheet metal work.s:2s:2
That will be the next mod to my Kilogram Roaster Project.
This PGR needs to be kept running so I can roast while I experiment with my PBER
(Pretty Big Electric Roaster)
When I rewired the PGR I also added the same insulation I had ordered for my new-project-Kilogram Roaster.
It turns out that the hi temp furnace insulation does not seem to be what is needed at these low coffee roasting temperatures.
Even though I had more of the hi temp stuff, the outer wall of the roaster gets HOTTER! s:4s:3
So forget about ordering special insulation. I recommend that you stay with plain fiberglass insulation. It is used for water heaters, walls, ceilingsand pipe wrap. It is fireproof and can be obtained from any hardware store or building supply outfit.
It works great in my PGR and the more expensive stuff seems poor in comparison
The outside of my roaster stays cooler to the touch when I use it instead of using the hi temp stuff.
Another few bucks in savings
Needless to say that I will be replacing the furnace insulation with fiberglass.
Sad day, our dear Micheal Guterman passed away last week. Many of you know him from Sweet Maria's and his notorious pens lists! Our prayers to his family.
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