SCTO Motor

[ph33nyx]

I'm just wondering if anyone has ever beefed up the motor on a stir crazy to something that runs a little faster than the stock. I'm not talking crazy fast, just around 25-30RPM.


Tex....where are you? 

[grinderz]

I think what a stircrazy needs is a little me torque more than anything else. Too much speed and the beans will want to migrate to the outside.

[ph33nyx]

I think what a stircrazy needs is a little me torque more than anything else. Too much speed and the beans will want to migrate to the outside.

That's another thing I was hoping to get out of it as well.

[grinderz]

Why? Are you doing small batches?

[ph33nyx]

The smallest batch I do is 3/4lb, largest is 1.5lbs.

[ScareYourPassenger]

If it is scorching then disconnecting the bottom heater might help.

[ph33nyx]

If it is scorching then disconnecting the bottom heater might help.

It's not scorching, and I have the bottom heater disconnected. I was wanting more agitation.

[Tex]

Would you get more agitation if you replaced the two-prong stirrer with a four-prong one? Same RPM - double the bean movement.

[grinderz]

That would provide more agitation but the motor is already torque limited so it would probably bog it down too much.

[blzrfn]

I have an extra set of arms on my stir crazy and have attempted somewhat successfully up to a 550g batch.  The roast is pretty uneven but the Galloping Gourmet has no lack of heat output so a faster/stronger motor would definitely be useful I think.  One that turns opposite to the air flow so it doesn't toss beans out the woz chaff ejector would be best.  I really want to play around with a bread machine motor, but haven't found the motivation to do so yet.

[ph33nyx]

Well it seems like this is a good upgrade discussion. I'll see what motors I can come up with and post the results.

[peter]

My thinking is if you're going to the trouble of swapping out the motor, you may as well start off with a fresh base altogether, like round skillet or electric frying pan with taller sides and flat bottom.

[sea330]

I have tried higher rpm motors from 15 rpms to 30 rpms that would fit in the StirCrazy enclosure with no luck. Higher rpm motors running at 120 volts ac has to low of torque. I would retro a 24 dc motor and pair it with a cheap dc power supply, that would give lots of torque, you can get these motors cheap on ebay and there small enough to fit on the StirCrazy. I am in the process of building  up a roaster using a 12" stainless steel pot, installed a high torque dc motor running up to 80 rpms. For control I am using a Watlow pid temperature controller with a K type TC to manage BT, I will be using the Watview data logging software from Watlow it is free all you need to do download it. You will need to purchase a RS485 to RS 232 adapter to communicate with the Watlow controller. I also removed the heating element from a StirCrazy and mounted on the bottom of the pot and wrapped it with high temp insulation, I also mounted a TC on the bottom of the pot to control the lower heating element temps. Hope this makes sense, I will post pics as soon as I get it up and running maybe a week or so. Happy roasting

[farmroast]

Stirring will always have it's limitations. To go high speed like I did (variable up to 220rpm top speed) a square bottom pot with 2 simple rod bean bats works well. The bean mass gets lifted off the bottom and whirls around the outside of the pot while the TO top blows directed air down the sides and into the whirling mass.
Super even roasting this way. Plus a very significant increase in convection and efficiency.
basically it's a mechanical driven fluid bed in concept with the advantage of very little introduced oxygen and better humidity in the roasting environment.

[JimsJava]

Here are two modifications I made on my StirCrazy stir rods that you might try to get more stirring action. I routinely do 19-20 oz batches in my StirCrazy/Convection Oven roaster:

On this one I carefully bent a rod (coathanger?) to suit my needs. I used it for awhile before trying the second mod.


With this mod I used some metal fasteners I stripped out of an electrical Terminal Strip I bought at Radio Shack - they fit perfectly on the stock stir rod. I added heavy gauge wire (coathanger? - there's a pattern here) to make the stir arms. I get very good stirring action with this modification. I think I stayed with this mod over the previous one because it handled a few more ounces better.


Since the photos were taken, I have also used JB Weld to permanently attach a "Woz Chaff Ejector" modification. This raised my convection oven about 1.5 inches above the beans giving me perfectly even roasts.