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AAARRRGGG! What machine is good for me?????

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  • #16
    Re: AAARRRGGG! What machine is good for me?????

    A few random points ...

    (a) Could our engineering brains trust comment on whether or not sunbeam might have chosen to SS coat an aluminium thermoblock for thermal properties?

    (b) Edward, if you want a machine in that bracket that makes thermal sense and is simple, why dont you check out the Isomac Venus or the ECM botticelli? Both of these machines have boilers directly on top of the groups, so I would think that the thermodynamically inclined side of you might find that more appealing than the silvias group, which mounted on a piece of brass that sticks out from the boiler.

    (c) Just for the sake of completeness; the grinder and the beans themselves are probably the most important part of the equation at the domestic machine level. I know that that gets banded around a lot, so sorry if Im boring anyone.

    (d) If you havent used a manual style machine before, you might want to give it a go before you buy it. Whilst the quality of what you produce will probably cane anything that a superauto could, be aware that (a) its more time consuming, (b) its more messy and (c) its not quite as easy as it looks.

    Cheers,

    Luca

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    • #17
      Re: AAARRRGGG! What machine is good for me?????

      Originally posted by Edward link=1181797670/0#14 date=1181816448

      This is what came to my mind when I drove to the post office. Insulating the entire machine with a removable insulation would be the easiest way. I just thought I wait till I can see a Silvia face to face and have a look if this might affect any other components. That is why I asked if there is a place to discuss these issues.

      Edward
      Edward....

      Insulating the whole machine is not a good idea.... some parts are designed to get hot and insulating these is fine.... but trapping the heat in so that everything gets hot...... may cause damage.

      Probably not as important as a machine with lots of electronics (EM6910 and any volumetric machine - domestic, prosumer or commercial or a machine with a built in PID).

      A good philosophy is to keep the heat where it should be.... and that is not the whole machine.

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      • #18
        Re: AAARRRGGG! What machine is good for me?????

        Hey Luca,

        Without doing any research I know aluminium has a high thermal conductivity. So no, I dont think it was put there for that reason. You can get heaps of different Al alloys such as 2000 and 3000 series which has Cu (copper) as the major alloying element, 5000 and 6000 series using Mg and so on. I would have to look up what each application for each of these alloys are suited to. I would imagine the 2000 or 3000 series being used because of the copper! But youve got me thinking and I think the stainless is there (again heaps of different grades of stainless) to retain heat within the thermoblock.

        Aluminium from memory has a very high corrosion resistance when an aluminium oxide layer forms (Al2O3). So not sure why Gaggia boilers suffer from oxidation....could be related to HTC but more likely to be galvanic corrosion when an oxygen rich area acts cathodic where you get the following (you do chem right Luca?). My theory of why Gaggia boilers and thermoblocks made from Aluminium corrode is this.

        2H2O + O2 + 4e- --> 4OH-

        To support the cathodic reaction, the adjacent oxygen deficient areas act anodic which generate electrons! This type of corrosion basically occurs in inaccessible areas such as cracks, crevices, pits (you get the idea) or under accumulation of dirt/corrosion products such as scale! Isnt that a killer...thats probably the most likely reason why Gaggia boilers corrode.

        With regard to the the corrosion between dissimilar metals, this can be mitigated by an insulation layer between both alloys (suitable insulation should be put in between the stainless lining and the Al thermoblock). Which in all honesty has probably already been done by Sunbeam!

        I might have to see the Doctor on this one...he really is a corrosion expert...raising over $1 million in research grants for corrosion studies.

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        • #19
          Re: AAARRRGGG! What machine is good for me?????


          Cant really comment on the machine of choice, but:

          Whats the issue with Aluminium?

          Why do you want to avoid it so bad?

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          • #20
            Re: AAARRRGGG! What machine is good for me?????

            read above...I just edited my post....could explain a bit...or nothing!

            Aluminium oxidation can be mitigated however!!

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            • #21
              Re: AAARRRGGG! What machine is good for me?????

              Aluminium has some health concerns its my main reason as well for wanting to upgrade.

              Andrew

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              • #22
                Re: AAARRRGGG! What machine is good for me?????

                Originally posted by Sarg link=1181797670/15#20 date=1181826075
                Aluminium has some health concerns its my main reason as well for wanting to upgrade.

                Andrew

                If you are talking about the link with Alzheimers, then I am pretty sure the original research has been discredited.

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                • #23
                  Thank you all for your great Input

                  Thank you all for your great input. I would have never thought that I receive such high quality answers.

                  I will look at the Silvia, the Isomac Venus or the ECM botticelli and buy one of them. I am confident that all 3 will create a latte better than my superauto and will allow me to create really good shots if I want to.

                  For those of you that wonder why I have issues with Alluminium: It made me sick when I was heavily using deodorants as teenager. Banning Alluminium out of my food and personal hygiene chain I quickly recovered.
                  I have had a slight decrease of health since starting with the superauto but I was blaiming it on my increased consumption of coffee (it is so easy and convenient).

                  For those of you that have a 6910. Please dont feel offendent that I dropped it out of my list basically because I am in general fed up with consumer quality products. I value longuevity and the ability to repair or modify things myself very high.

                  Once I have my grinder and machine I will come back and contribute to this forum with my experiences.

                  Thanks,
                  Edward

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                  • #24
                    Re: AAARRRGGG! What machine is good for me?????

                    FYI Edward, there has been not stock of the Botticelli in Aust for quite some months. ECM Italy have insisted on minimum quantities of 1000 units.....I guess thats a big ask for any country other than the US.

                    There is this one, but its pricier....

                    Alternately, save some cash and get a Silvia and grinder instead. You wont regret it....

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