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Pneu-Presso

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  • Madhatter_jc
    replied
    Re: Pneu-Presso

    Ahhh, just what I needed.

    My Presso plunger cracked on me, and I was getting the portafilter undoing when I used max power too.

    mod time ;D

    Leave a comment:


  • gonzob
    replied
    Re: Pneu-Presso

    Originally posted by 656F7A6D6D627670030 link=1321770018/25#25 date=1329259095
    Have you noticed any improvement in the cup compared to the stock standard Presso?
    Yes. The crema is significantly better, there is more body, and you dont damage the puck (and therefore the extraction) by "having another go" to get a double shot. Its like a high capacity lever machine.

    Originally posted by 77336576030 link=1321770018/26#26 date=1329260218
    and lets you squeeze the handles as hard as you like!
    Thats true, but my analysis says that youre going to be lucky to get 3 bar. Its also physically quite taxing on the operator and the equipment. I ended up damaging my clear plastic barrel by locking the portafilter too hard in an attempt to get high pressure.

    Gonzo.

    Leave a comment:


  • t0fu
    replied
    Re: Pneu-Presso

    There is a little trick if you want to get more pressure out of the normal presso without going to pneupresso! Not sure how much extra pressure but there is really no limit.

    What you do is continue filling the top chamber with hot water and give the handles a little wriggle when doing so. This gets rid of the little cushion of air and lets you squeeze the handles as hard as you like!

    Leave a comment:


  • flynnaus
    replied
    Re: Pneu-Presso

    Very impressive. With the flow control using pressure variation, you are getting into lever machine territory. Have you noticed any improvement in the cup compared to the stock standard Presso?

    Leave a comment:


  • gonzob
    replied
    Re: Pneu-Presso

    Heres some more pics:

    The unit:


    The air pressure plumbing:


    The water drain tube:


    The brass base with valve and bayonet fittings:


    Inside the copper tube showing the valve and drain tube to the base:


    Gonzo

    Leave a comment:


  • artman
    replied
    Re: Pneu-Presso

    Wow, great work!! [smiley=thumbsup.gif]

    Cheers

    Leave a comment:


  • gonzob
    replied
    Re: Pneu-Presso

    NOW MkIII

    Ive now re-worked the Pneu-Presso.

    The original Presso is good but has some limitations (in my opinion). They are:
    • difficult to get hot enough
    • cant get a double shot without "pumping"
    • cant get high pressure

    My Pneu-Presso (MkI and MkII) improved on the second and third of these, but I couldnt get it hot enough or high enough pressure because of the limitations of the PVC material.

    Now for MkIII...

    [media]http://www.youtube.com/watch?v=T-Y8VTS8OEI&feature=plcp&context=C3885172UDOEgsToPDs kJtugVwkIqYgxzsDU-ikDZw[/media]

    Gonzo

    Leave a comment:


  • gonzob
    replied
    Re: Pneu-Presso

    What happens above 4.5 bar? Well, the seal between the portafilter and the pressure cylinder leaks a bit, and fills up the space between the cyl and the presso body with water. I think its just not designed for high pressures. Ive tried locking it in tightly, but it still leaks a bit.

    Anyway, 4.5bar gives a good crema, but quite a bit darker crema than Ive had before. I dont know what that means.

    Gonzo

    Leave a comment:


  • kettle
    replied
    Re: Pneu-Presso

    Just saw this. Excellent idea.
    Looks like a hybrid of the presso and airspresso.

    Neat!

    Leave a comment:


  • SniffCoffee
    replied
    Re: Pneu-Presso


    This is brilliant mod (as a former Presso user).

    I agree with two pulls on the Presso unsettling the puck - the flow for the second pull was always faster.

    But I also recall getting some pectoral trembling pressure going on my Presso - have you tried cranking the Pneu-Presso up above 4.5bar?

    Sniff

    Leave a comment:


  • gonzob
    replied
    Re: Pneu-Presso

    And heres a photo of the shiny (well, brass) bits:



    Re a pressure tank and CO2 bulb - I tried to keep the volume of compressed gas down to a minimum, so that if anything went bang thered be a minimum of stored energy. Now that Ive used it, I think thats less likely. However, the pressure doesnt vary much (max 1/2 a bar), so I think the tank might be overkill. Ditto for the CO2 bulb.

    PVC & food safety? Yeah, PVC pipe is used for drinking water, but not at 100c. That said, any diffusion of something into the water (vinyl monomer?) would be dependent on both time and temp, and the time is less than 1 min.

    Brass? It would be lovely, except that youd have to do a heat-up flush. Im getting a hot espresso using no pre-heating except for the cup (naked portafilter helps).

    BTW, the spare bits for my Presso arrived finally. I might just put them on the shelf and spend some more quality time with the Pneu-Presso.

    Gonzo

    Leave a comment:


  • MrJack
    replied
    Re: Pneu-Presso

    Originally posted by 5D55544055583A0 link=1321770018/14#14 date=1322026362
    Ok, ok,

    So, MrJack, you dont like my bike pump? I think it adds a certain artisan touch...

    Gonzo
    Not saying that at all. I just have a bit of a problem when it comes to modifications.

    Leave a comment:


  • Javaphile
    replied
    Re: Pneu-Presso

    Originally posted by 607C6161767D677A7D72707C75757676130 link=1321770018/15#15 date=1322027187
    Is PVC foodsafe?
    It better be as PVC piping is used for much of the worlds fresh water pipes.

    Originally posted by 607C6161767D677A7D72707C75757676130 link=1321770018/15#15 date=1322027187
    could you have a small pressure tank- you could pump it up to pressure before you start- then open a valve and let it rip?
    Yup, it would be a relatively simple mod.


    Java "Great mod!" phile

    Leave a comment:


  • sorrentina
    replied
    Re: Pneu-Presso

    Hey- this really is great thinking...

    Is PVC foodsafe? How would a brass cylinder with PVC insulation go?


    if you could add one of these to the lid it could be just the ticket?



    http://www.houseneeds.com/shop/Heati...eindexpage.asp

    also- could you have a small pressure tank- you could pump it up to pressure before you start- then open a valve and let it rip?

    Leave a comment:


  • gonzob
    replied
    Re: Pneu-Presso

    Ok, ok,

    Heres the MkII version:

    [media]http://www.youtube.com/watch?v=OfC8V9ifzN4[/media]

    So, MrJack, you dont like my bike pump? I think it adds a certain artisan touch...

    Gonzo

    Leave a comment:

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