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Ultimate DIY Roaster

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  • Ultimate DIY Roaster

    Hi Coffee Snobs,

    I've been meaning to start a thread to share with you my roaster I built for a while now, so here it is...

    I built it at work in my spare time, which took a while because spare time is hard to come by these days. I'm an Engineering Fabrication tradesperson, so building this sort of thing comes second nature to me. I started off with a colander that I got at a super market for $10, which was to become the drum, and I built everything around that. For quite some time that is all I spent on it, as I was lucky enough to be in a position where I could utilise scrap steel as my materials. I also had access to a machine shop where I could have some machined items made along side official jobs, and there was a range of machined parts surplus to the companies needs that I repurposed. So the majority of the build cost me nothing but time.

    So towards the end of the build it became time to fit out the shell with the essentials to making this thing work, the initial $10 cost started to grow. I put in 2 DC gear motors for the drum rotation and cooling bin agitators $30 each, 1 DC direct motor for the fan $80, the fan was $30, and 3 PWM (Pulse Width Modulation) speed controllers $50 each. All of which run off a 24v circuit powered by an AC to DC unit I had lying around the house. Then came the heating element, gas was my choice of heat source. I picked up 4 burners from the hardware store $20 each, along with 4 gate valves $5 each, 1/2 inch copper tubing $30, and some fittings $40. I then made a 5th burner out of some stainless tube left over from a previous project, and robbed my BBQ for a valve to supply it. This was to become a booster burner to ramp up the heat when needed.

    Once it was all wired up and plumbed in, the trials began. Ran it with beans cold and had some issues with beans getting jammed between the drum and face plate. I got some cork gasket material to act as a bush which solved the problem $15. I also changed the drive pulley to a smaller diameter to give it more torque. Then it was time to run the burners, robbed some more parts from my BBQ, igniters and bottle regulator, and it was on. Got up to about 420 degrees C before turning up the fan, then down it came to about 240. Which brings me to the final expense, the temperature measuring device. A TC4C arduino $130 with 2 K type thermocouples $5 each. I was satisfied the contraption was going to do the job, it was time to roast some beans.

    Have you done the maths? Total build cost came to around $625, if I've added that correctly, and about 8 months worth of spare time. I've done 6 roasts in it so far with varied durations ranging from 15 mins to 25 mins, I'm sure it will become more consistent as the drum becomes seasoned. The batches have been 500g and I have had 1kg in it cold. So over all I'm extremely pleased with it. Heres some pics, and I'll be sure to keep you up to date as I go. Tell me what you think...
    Attached Files
    Last edited by MartyMac; 26 September 2014, 11:22 PM.

  • #2
    Fantastic work Marty...

    A terrific achievement; will look forward to many more posts (and piccies) of roasting efforts as you gain experience with your beaut roaster.



    • #3
      Super impressive...


      • #4
        That's an amazing looking machine!! Great work!


        • #5
          Very nice,


          • #6
            Luv it, i'm handy................but not in this league, great work.



            • #7
              Here's a few more pics...
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              • #8
                Excellent! Envious of your mechanical aptitude and skills!


                • #9
                  What an awesome DIY !!



                  • #10
                    You using the TC4 to do any control or is it just reading temps?


                    • #11
                      Originally posted by fg1972 View Post
                      You using the TC4 to do any control or is it just reading temps?
                      At this stage it is reading only the temps, but I intend on hooking up the PID side of it once I get my hands on a LPG solenoid valve. Then I will hook it up to the fan control and the booster burner.


                      • #12
                        Wow that is totally amazing, well done Marty!!


                        • #13
                          Very nice DIY indeed!

                          Java "Love the lines!" phile
                          Toys! I must have new toys!!!


                          • #14
                            Wow that's awesome


                            • #15
                              If your not careful u might need to quit your day time job and start taking orders.

                              Was the concrete mixer next to it much help