Homeroasters - Home Roasting Coffee Community » ALL ABOUT ROASTERS » Heat Gun Roasting
Who is here? 1 guest(s)
 Print Thread
She's ugly but she's mine!
Bazzie
Top  #1 Print Post
Posted on 03/25/2018 3:48 PM
So I mentioned elsewhere that I started popping 2-3 yrs ago with a popcorn popper and finally got tired of doing so many small batches. Also, roasting was not very even as the popper blows air from below, not the best arrangement I suspect. so I read up quite a bit and eventually saw a very simple setup using a heatgun, and decided that would work, as I had a spare lying around that I bought for about $14. First was the drum, I bought a SS canister from an op-shop for $3. Next the drum motor - started with a stepper I had lying around, it was too noisy so I went to the scarp metal joint in the next town and bought a 60:1 gearbox and a motor for $3. I had some pillow blocks left over from a CNC machine I built, threaded rod and some other parts I needed. TC of Aliexpress, Arduino with a 4-line display, and the software has 2 modes, both using an Arduino PID library. The first one had a hard-coded profile, and later I figured out how to interface it to Artisan using the MODBUS interface, so developed a second mode for roasting with Artisan feeding the target roast profile to the Arduino. I then took an old Centrino core2 Dou laptop I got from a friend, it was short RAM and HDD, so again off Aliexpress memory and SSD on the cheap got it going. I run the fan off a 12V supply, running it standard tends to blow a bit hard and I don't want too much airflow through, figured it may do more drying than I would like. These motors are more or less made for 18V. I use a zero cross SSR I had lying around to control the heat, and have both coils running off the SSR. I also use a 1sec period for the PWM for heat control. I found that the usual recommended 2sec creates problems for the PID loop and 1sec is completely adequate. There is only one shortcoming, the TC measures ET, not BT as it protrudes through a hole in the screen that covers the roasting drum, and of course with a rotating drum, the hole needs to be in the middle. V2 will have a SS front, screen / lid removed and the TC will be in a position where it will measure BT. All this meant is I had to do more trial and error to get the profiles right, but then I could run very small batches so there was fairly little that was completely horrid. We did drink quite a bit of less-than-ideal coffee along the way though Shock
I've had to actually drop the target temperature after first crack (we usually roast quite light, depending on the bean), got that figured out over the weekend so finally we're having good coffee again! I will post a picture once i figure out how to - probably need to go store the pic somewhere online and then link to it, just need to find out where!
 
Josh025
Top  #2 Print Post
Posted on 03/25/2018 5:53 PM
Do you have any photos?
 
Bazzie
Top  #3 Print Post
Posted on 03/25/2018 6:12 PM
Yes I do, I tried to post it this morning but in the preview it didn't show up, so I deleted it again. I used the [img] tags, was on my laptop screen so missed the Browse fr attachment option below Grin
Let's try again...
Bazzie attached the following image:
img-1133.jpg
 
Bazzie
Top  #4 Print Post
Posted on 03/25/2018 6:20 PM
So the fan on top of the PSU bottom right is for cooling - I unplug the heatgun fan and plug in the cooling blower which works really well, much better than using the heatgun fan which would still be blowing through a warm ceramics block.

I've already got some of the bits for converting this to something closer to large commercial roasters - I have a gas burner on its way, and I will add a SS 90deg bend at the top via which to charge and dispel smoke and chaff, and a door at the bottom to drop. Also making plans to build a cyclone. I also got some perforated SS from the scrap metal dealer, so may be building my own drum, but before I can do any of this, I have to build a spot welder. So many projects, so little time Grin

we're planning on eventually getting a Huky - perhaps late this year, so whatever I do, I want to keep the costs as low as possible and maximise reuse.
 
JackH
Top  #5 Print Post
Posted on 03/25/2018 8:20 PM

Quote

Bazzie wrote:

Yes I do, I tried to post it this morning but in the preview it didn't show up, so I deleted it again. I used the [img] tags, was on my laptop screen so missed the Browse fr attachment option below Grin
Let's try again...


"Preview Reply" does not work for attached photos. Use "Post Reply" instead.
---Jack

KKTO Roaster.
 
Josh025
Top  #6 Print Post
Posted on 03/25/2018 11:31 PM
That's impressive. I need a motor setup like that for some cooling arms on a bean cooler.
 
Bazzie
Top  #7 Print Post
Posted on 03/26/2018 2:00 PM
Yeah I was a bit lucky with that one, the gearbox is worm-based, 60:1 and the motor is very high turn, definitely somewhere between 55 and 80T, only draws about 250-300mA while driving the drum and the motor has a lot of torque. The gearbox is also very smooth, almost no resistance so it drives the drum very quietly.
 
renatoa
Top  #8 Print Post
Posted on 03/26/2018 2:34 PM
You can consider a 68KTYZ for this job, or even a 60KTYZ, for less than 1kg, as I am using atm.
They are available in a broad range, 10 to 80 RPM.
 
Josh025
Top  #9 Print Post
Posted on 03/26/2018 10:02 PM

Quote

renatoa wrote:

You can consider a 68KTYZ for this job, or even a 60KTYZ, for less than 1kg, as I am using atm.
They are available in a broad range, 10 to 80 RPM.


You're my hero. Gonna grab that 10 rpm model for my bean cooler arms good post
 
Jump to Forum: