Thread subject: Homeroasters - Home Roasting Coffee Community :: Kilogram Roaster Project

Posted by peterz on 01/28/2006 3:00 PM
#1

The pics of the motor are great s:2
I plan to use a heavy power cord into the mixer unit with an outlet on it to plug the GG into. There will be a switch on the motor, and a switch for the heater coil which can easily be converted to run with a PID. The fan in the GG can run all the time as will the fan that comes with the bread machine :)
It may be possible/necessary to stack two heater coils in the GG setup Grin
Will this mean a larger fan?
One Turbo oven I tried had so much fan power that the beans blew out of the bowl Shock
That one had a Hi and Low selector, but was only 1200 W:(

Posted by peterz on 01/28/2006 6:48 PM
#2

Modified the dog bowl today to use as a motor housing.
Will have pics so you can see how it is important to use a template right side up or you wind up with extra holes s:3
You can still tell it's a dog bowl though ;)
Am thinking of using a SS wok directly above it to provide the outer shell for the lower half of the roasting bowl. There is about an inch gap for insulation Grin
Pics soon, still need to come up with the top part of the outer enclosure, and decide if only an inch gap is enough.
May use some SS sheeting in this also.

Posted by Mike on 01/28/2006 10:17 PM
#3

Peter,

You're making me feel guilty. :( I lost momentum on my project and have just been working on my shop. Maybe the guilt will get me off my butt and get going again.

Looks like your making a lot of head way.

Mike
B)

Posted by peterz on 02/03/2006 1:28 PM
#4

Frankly the woks and other stainless bits are difficult to work with :(:(
so I became a bit discouraged with all the bench time. s:7
Now I have decided to do whatever it takes to partition the roaster for insulation, drive assembly, electronics etc, and then cover it over with nice smooth stainless steel.
It was a hastle trying to figure how to get the insulation in tight around the bowl and still have it look good and be able to take it apart easily.

Pictures will better describe it. Coming soon.
PeterZ

Posted by peterz on 02/11/2006 12:41 PM
#5

Sorry about the delay.. been down with the flu s:7

The very top rim to surround the chamber was drivng me crazy s:4
No way to get a SS pan or wok the right size or shape.. then it occurred to me:
Why not a SS hub cap? Off to the local thrift shop with tape measure in hand.
YES! s:2
$1.50.. a great investment s:2
The perfect top to my roaster Grin
Not SS, but chrome is okay also :)

Posted by peterz on 03/31/2006 2:08 PM
#6

This is a slow going project for me. Part of the problem is that I really like my PGR and it does well enough roasting about 3 pounds net in two batches:)

The other thing is that I have been spending time repairing the PGR. :(

Today I was having trouble with slow heating and found some more connectors fried from current overload.
No wonder since 18 Ga wire runs the heating element ;)
The factory did that, I did not. I have been using it pretty much stock.
Not bad performance for all the roasting it has done over the past year. Several hundred pounds! s:2 s:1
Bear in mind that it is an experiment to see how to make improvements for the one I have in progress. Grin

The new roaster is wired throughout with 10 Ga. A separate switch for the motor and heater on the turbo oven. (This will allow PID perhaps).
Next a 10 Ga circuit right from the house breaker panel to plug it in to.
I tested the new TO assembly and it drives up the temperature on the PGR at about 2 degrees F per second. About twice as fast as the factory wired unit.
Ya gatta love 10 gage wire! s:2B)

Posted by peterz on 03/31/2006 2:14 PM
#7

So I bought and cut up several hub caps to use around the outside of the top of the roaster (need to think of a name for the new one).
When I finally got one that was aesthetic enough, it did not fit with the Turbo oven assembly! Shock:@:( s:8

So I tried the TO on a wok.. nice.:)
It fits in the groove of the stock pot lid, and allows an inch of insulation right to the top of the chamber.
There are several ways to attach the section of wok, and I am still working that out.

Pictures to come!

Posted by peterz on 05/26/2006 3:03 PM
#8

So I have been lazy Grin s:6

The roaster has been finished for a while, at least to the point of being useable. s:2
Getting the skin on and making it beautiful? are other issues. s:3
So Today I am doing the first roast. 1278 Gr (44 oz) because that is what is left of the Robusta I have been test mixing with.B)

Not good so far, while pre heating, the fan on the Turbo Oven stopped! Shock :(

Found out that the cooling fan is rubbing on the silicon insulation. When it gets hot it expands and wrinkles. s:8s:8

Will just remove it from the fan area..

PeterZ c:3

Posted by peterz on 05/26/2006 5:06 PM
#9

:)
Just finished the break-in roast and I am covered with chaff s:8s:8s:8

Finished with 1058 Gr Grins:2
No beans were lost through fly out! s:2

To start with I pre heated the chamber up to 440F. When I dumped in the beans it took about three minutes for it to stabilize at 228F.
The temperature slowly climbed and was at 350F in about 12 minutes.. not bad.. Grin

From there it went even more slowly, so it seemed.
Honestly, I am not used to roasting so much at a time, especially Robusta!.
There was lots of smoke when it got near 400F.
At 415F I cut the heat for a beat.. so much smoke it must be in first crack by now !
Could not hear it. :(
Lifted the lid a bit.. yup, crack going on, but not sure if first or second.
So much smoke I could not see the beans.

Stopped the roast at 430F.. by removing the heat. 18 Minutes :)
Proceeded to cool it with my hair dryer. s:6 s:3 Shock
Yup, I know it will be slow, but I want to know how slow...
Gosh 6 min and only down to 350F..:(
For sure the beans need a better way to be cooled..s:8

The beans are all nice and evenly roasted :) s:2 s:2

Problems to fix:
Improve insulation s:2s:2

When I put the outer skin on, the insulation will go to the top of the bowl :) s:2

It would be great to insulate the top of the TO, around the motor.. if only with some foil covered insulation or something similar that could be removed. Donut shaped.

This roaster uses a shielded thermocouple. So I need to learn what temp the cracks are at.
It is simple to lift the lid for a second and listen.. s:8s:8c:1

Get more power! s:2 s:2
Still using the power supply with a 12 Amp breaker on it. Need to wire in a 30 Amp
circuit so I can take advantage of the 10 gage wire in the heater section.
There is a 30 Amp unused breaker in the main circuit panel. B)
I could not wait any longer to try this out though c:2 c:1 s:8 s:8

PeterZ c:3

Posted by Mike on 05/26/2006 6:51 PM
#10

Peter,

Congratulations. It's got to feel good - getting results this positive with a new project, first time out of the gate.

I'll be using you for inspiration - hopefully that will help me get more of my project going.

I'll bet a 20 amp circuit would be plenty of power, but if you have to pull new wire - I'd go for a 30 also (a little extra safety margin never hurt anything).

Again, a sincere Congrats s:2s:2

Mike
B)

Posted by peterz on 06/02/2006 5:24 PM
#11

After the first roast or two, I have been giving some thought to adding more power!

You can build heater coils to any shape, and bend the thicker one also, but I have in my
collection a 1200 Watt example that will mount just below the GG coil B)s:2
The only modification is the sheet metal bracket that holds it needs to be trimmed.

It already has high temperature wires and they are attached to the element with SS screws!:)s:1
None of this was apparent until I took it all apart :)
Other than that this unit is cheaply made, a newer model. All the screws that assemble it are self tapping, and it is otherwise very light plastic.
Nice element though Grins:1s:2
Will it still just be 120V if I run one element on one circuit and the other on another circuit?

s:8s:8s:8s:8

PeterZ c:3

Posted by Mike on 06/02/2006 8:43 PM
#12

I'd call it 120 V?. s:8

Mike
B)