Robo-Pavoni; learning to make espresso machine from scratch - Page 2

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matadero210 (original poster)

#11: Post by matadero210 (original poster) »

I added mineral insulation to the robo-pavoni. It now sits with 0.1C stability, with a shot recovery time of 1-2 minutes. There's a quick snaphot at my grinder thread Home-made grinder. I hope to add a splash guard or boiler cover, but its working fine without.

raj
LMWDP 117

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espressme

#12: Post by espressme »

matadero210 wrote:I added mineral insulation to the robo-pavoni... snip...but its working fine.
raj
Wonderful prototyping! Thanks! :D
richard

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arriflex

#13: Post by arriflex »

Love it!! I've got a cnc mill that I'd really like to use to build a head since those don't exactly come up every day. Any ideas about what you'd want to see in such a project? Or for that matter have you seen anything like it done? I've been following the progress on the portafilter build olympia cremina 67 portafilter as well. I'll keep all drawings and progress public if I actually get around to doing something other than 'thinking off.'
arri

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Chert
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#14: Post by Chert »

Some people dream of good ideas and realize the simpler ones (blokes like me). It looks like matadero210 manages even the complicated ones. Now if only Expobar or the maker of the Vivaldi - not La Marzocco as it would be impossibly expensive - would buy Raj's idea from him and make the temperature-and-pressure-dialable-manual (Why not dual head, one manual and one spring operated) lever wondermachine! Great thread.
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mhoy

#15: Post by mhoy »

Any updates on this amazing machine?

Mark

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matadero210 (original poster)

#16: Post by matadero210 (original poster) »



Here is the complete kit, fully working and tested. From the right:

1. Robo-Pavoni. This is a pavoni head bolted to a home-made copper boiler and brazed-steel frame. The head has been drilled to show piston pressure (dial). The boiler is insulated (kinda ugly, but not to me) with fiberglass and has an anodized aluminum spray skirt (not cleaned in this photo) in case of shooters. The PID is on the back and is normally set to 90.5C. The system is plumbed directly to my cold water house supply with a 1.7bar regulator (with no back-pressure relief). When the piston is raised, the pressure increases to 3bar for the the initial pre-infusion as the gas bubble trapped in the top of the boiler compresses. Final pre-infusion happens at 1.7bar. Typically the boiler temperature fluctuates during the pull, but since the water is already in the piston this does not affect the pull temperature. By the time the shot is pulled, the boiler is back at 90.5. System takes < 4 minutes to be ready in the morning and can pump shots until the Hetch-Hetchy runs dry. Dry-pumps can circulate boiler water through the head before shooting. I also can keep the lever raised and flux liters of water through for daily cleaning.

2. Typical shot of beans on the 3rd day. On day 1 I get way to much crema.

3. Zassen-Robur. This is a single chunck of brass milled into a hand-crank grinder. The burrs are from the Mazzer Robur, the crank from an old Zass with broken burrs, and the rest from McMaster-Carr. The adjustor screw is 100tpi on a 3/1 lever, giving 80um/turn of adjustability. Its too heavy and hard to turn for my wife but it fits my hand just fine. About 30 turns for a 1.5x shot (what Pavoni calls a double, but I use a single pull with jiggles).

4. WDT tool and naked portafilter.

5. 1.6kg stainless tamper. One side is slightly larger, for the first tamp. Tamping is done by resting the tamper on the basket filled with grist, giving a half twist, and repeating with the narrower side. The pressure comes entirely from the 1.6kg--I don't push.

6. The newest member of the team, the Roaster. The guts are from a $10 popper from target, coupled with a multi-step, ramp-soak controller from auberins.com (same as the Robo-Pavoni's simple PID controller). One switch is used to toggle fan speed (low and high speed) since the beans are larger/lighter near the end of the roast. The T thermocouple is lightweight SS jacketed and at the center of the roast chamber. The screen in the background is the chaff collector, placed over the unit in operation. Typical roast is 80g: 4 minutes between 125C and 140C, then 8 minutes ramping from 180C to 230C, for Full City. Cooling is in-place and takes just over 1.5 minutes.

Can't think of any more coffee stuff to build. Maybe a reflux still .....

raj
LMWDP 117

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sweaner
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#17: Post by sweaner »

Yeh, I made all similar stuff....Ok, just the WDT tool.....OK, it is just a bent paperclip. :roll:

Seriously cool stuff. I wish I had the ability.
Scott
LMWDP #248

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r-gordon-7

#18: Post by r-gordon-7 »

And I'd probably cut myself while trying to bend the paperclip! I can't begin to imagine how Raj could do all this - So very impressive!

r-gordon-7
r-gordon-7
LMWDP #188

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matadero210 (original poster)

#19: Post by matadero210 (original poster) »

Thanks, guys. You'll notice that my "chaff collector" is just an asparagus steamer basket--I only build when I can't buy what I want.
LMWDP 117

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espressme

#20: Post by espressme »

Raj,
You seem to take a whole lot less parts than Rube Goldberg to perform a useful function! :D
Very, very, well done!
sincerely
Richard
richard penney LMWDP #090,