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Hands free Heat Gun

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  • Hands free Heat Gun

    After struggling with the popper to get hot enough during the cold winter days in Hobart I decided to resort to the heat gun.  It didnt take long to get tired of stirring so I bought an old sunbeam mixer from the local tip shop ($10) and modified the beater by replacing the blades with a flat aluminimum strip.  On the mix dry ingredients speed it stirs up to 2 cups of beans nicely.  The heat gun also hangs  over the handle pointing into the bowl at just the right height to roast in about 15 minutes.  I put a damp cloth under the bowl to stop the base getting too hot. Picture attached if I got it to work.


  • #2
    Re: Hands free Heat Gun

    Nice! Maximum MacGyver points.

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    • #3
      Re: Hands free Heat Gun

      Last photo was bit big, here is a close up of the results in the bowl.

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      • #4
        Re: Hands free Heat Gun

        Looks like a great little setup there Semaj! Congrats!

        Java "Gotta love a good home rig!" phile
        Toys! I must have new toys!!!

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        • #5
          Re: Hands free Heat Gun

          Great roaster project 8-) Very simple and looks like it would make it easy to be consistent in roasts. A couple of questions, how hot does the shaft of the mixer get? And do all the beans get passed/heated by the static heatgun position?

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          • #6
            Re: Hands free Heat Gun

            The shaft of the mixer does get too hot to touch but so far it doesnt seem to have affected the body of the mixer. The old mixers have a pretty solid steel body compared to the more modern plastic ones. The beans do get thoroughly mixed and roast more evenly than I can get by hand stirring as they are moving continuously at a much faster pace.

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            • #7
              Re: Hands free Heat Gun

              Hi Semaj,

              A short length of suitably sized PTFE tubing on the shaft might help to prevent direct heating from the heatgun blast, would only leave conduction from the beans then. Could be a backup plan if you start to notice grease melting in the gearbox and dribbling down the shaft. Would bring a whole new meaning to "oily" beans.... Yuck! :P

              Mal.

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              • #8
                Re: Hands free Heat Gun

                Thanks for the tip Mal, excuse my ignorance but what is "PTFE"?

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                • #9
                  Re: Hands free Heat Gun

                  Teflon But Mal has opened up a Can of worms here..
                  From Wikipedia..
                  While Teflon itself is chemically inert and non-toxic, Teflon begins to deteriorate after the temperature of cookware reaches about 500°F (260°C), and begins to significantly decompose above 660°F (350°C). These degradation products can be lethal to birds, and can cause flu-like symptoms in humans (see Teflon flu). By comparison, cooking fats, oils and butter will begin to scorch and smoke at about 392°F (200°C), and meat is usually fried between 400–450°F (200–230°C), but empty cookware can exceed this temperature if left unattended on a hot burner. A 1959 study, conducted before the FDA approved the material for use in food processing equipment, showed that the toxicity of fumes given off by the coated pan on dry heating was less than that of fumes given off by ordinary cooking oils.[1]

                  A 1973 study confirmed the FDA findings and found that a 4-hour exposure to the pyrolysis products of butter in an uncoated pan were 100% toxic to parakeets at 260°C, whereas no deaths were observed for exposure to Teflon pyrolysis products until the Teflon coated pan was heated to 280°C.[2] Over the 40 years non-stick cookware has been in widespread use, there is only one published case of a minor, short-lasting health effect linked to overheating non-stick cookware.[3]

                  The EPAs scientific advisory board found in 2005 that perfluorooctanoic acid (PFOA), a chemical compound used to make Teflon, is a "likely carcinogen." This finding was part of a draft report[4] that has yet to be made final. DuPont settled for $300 million in a 2004 lawsuit filed by residents near its manufacturing plant in Ohio and West Virginia based on groundwater pollution from this chemical. Currently this chemical is not regulated by the EPA.

                  In January 2006, DuPont, the only company that manufactures PFOA in the US, agreed to eliminate releases of the chemical from its manufacturing plants by 2015, but did not commit to completely phasing out its use of the chemical. This agreement is said to apply to not only Teflon used in cookware but in other products such as food packaging, clothing and carpeting. DuPont also stated that it cannot produce Teflon without the use of the chemical PFOA, although it is looking for a substitute.

                  It is noteworthy that PFOA is not part of the finished product of nonstick cookware or bakeware. It is only used during the manufacture of the product and only a trace amount of PFOA remains after the curing process. There should be no measurable amount of PFOA on a finished pan, provided that it has been properly cured.[3]

                  PTFE powder will react violently when combined or heated with powdered metals such as aluminum and magnesium to form carbon and the metal fluoride. Powdered PTFE is used in pyrotechnic devices and some solid fuel rocket propellants. [citation needed] When PTFE coated stir bars are exposed to a solution of solvated electrons in liquid ammonia the surface is converted to carbon.

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                  • #10
                    Re: Hands free Heat Gun

                    Gday Tepin,

                    My thinking was along the lines that since Coffee Roasting occurs mainly at temperatures below 230deg C with air as the transport mechanism, PTFE would be safe to use. Short of aiming the heatgun at the PTFE directly from short range (not apparent in the photos attached by Semaj and not likely the normal mode of operation), my understanding was that the PTFE would not be exposed to temperatures in the ranges where measurable emissions occur. And if by some chance some small degree of emission was caused, this would be taken out of the bowl about as quickly as it was produced. I am not an Industrial Chemist specialising in this field however so am prepared to stand "educated" should a compelling explanation be put forward.

                    Is there a less contentious material that could be used for the above purpose Tepin? I suppose an alternative to mitigating the transmission of excessive heat into the gear-box, would be to use special purpose extra high temperature grease in the gear-box... I am not familiar with any that might be suitable for the purpose though and also considered to be food safe. Any ideas?

                    Mal.

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                    • #11
                      Re: Hands free Heat Gun

                      It would be easier to put an Ally heat sink on the shaft.. The Problem with Teflon is the PFOA..
                      PFOA has lower Melting and Boiling points than the Teflon, Im not an Industrial Chemist but do have access to some..
                      Google Bucky Bailey and find out why DuPont eventually agreed to pay $50m in cash to the plaintiffs, plus $22m in legal costs. The company also agreed to spend $10m on special water treatment facilities to filter out PFOA.
                      Do You Micro Popcorn for the Kids -If you do/ Chances are you have High Levels of PFOa in yr bloodstream/ But then again its only categorised as a Likely Carcinogen..
                      FWIW there are Specific Food grade High temp Greases out there..

                      Comment


                      • #12
                        Re: Hands free Heat Gun

                        So far melting of the grease has not been a problem and I think if it was going to happen it would have by now. I suspect the grease dried up many years ago and on the speed I run it, it probably doesnt matter.

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