Quest for the best espresso Pt. 5

We left off with the completion of the first of three phases last time. With this blog I will be starting the second phase the "steam vessel" this will be dedicated to the creation of wet steam for steaming milk. No more sharing the brew chamber with the steaming function or any wait time to cool down after using the steam. This will also let us control the steam pressure as well as the the temperature of the steam will be created. Depending on how this works the steam phase will need to be revisited and a one way valve my need to be placed on the line to keep the water and steam from flowing back into the brew chamber.

So to star this phase I got all the fittings I needed together and made a quick dry build to ensure that I had all the part and that they fit properly. The parts that are show are: a 2nd Rancilio boiler, a modified base to match group head fitting with out the group head, a site glass build, and misc piping fittings (these will depend on the size of you site glass and boiler).

Once I was happy with the dry build I was ready to set the parts together with pipe sealer. I didn't use Teflon tape. Teflon tape is entirely to easy to tare when you are trying to seat the fittings properly. For this I used a putty and PTFE mixture to seal the pipes from leaking steam and water. Don't worry this sealant is rated for 350 degrees and 1000 psi for gas (i.e. steam). It is also food and potable water safe. So with the putty in hand I built the hardware side of the steam boiler.

Now that the hardware was together I started shaping the soft copper piping that will form the steam line to the steam wand and serve for the bottom of the site glass connection. I had the left over copper pipe from the main boiler (remember I use the pipe to attach the pressure gauge). While as I was curving the end back around to meet the fitting, I did the worst thing you can do to copper pipe... I crimped it. To top it off I had not realized that there was so little pipe left so I had to call it at night at this point because Lowes was closed at this point.
Next time I will be attaching the soft piping and placing the boiler inline with the system. So join me next week when I attempt to mold copper piping again. Dan ~

The Old Wwworld Cafe

Quest for the best espresso Pt. 3

With the parts on hand that I needed to create the first phase of the espresso machine, I started assembly. This started with an overhaul by removing the old replaceable parts on the boiler such as the boiler gasket and the head groups shower screen assembly. This allowed me to clean all old oils and mineral buildup from the the previous owner, and also was necessary to when dismantling the boiler from the group head.

So with the boiler apart I started to mount the RTD by drilling, yes drilling, into the side of the boiler. This was the best way to have an accurate reading of the internal water temperature. This was followed by threading the driller hole for a pressure threaded screw. I prepped the screw I was using by drilling a 1/16 in hole down the center of the screw and inserting the RTD through the hole along with a high temperature and pressure rated epoxy. The bottom of the screw was filled in with a high temperature food grade silicone to keep the water from contacting the epoxy.

Once the epoxy was set and the "RTD Screw" was mounted and the boiler was cleaned it was ready to be assembled again. This was when the real fun of the project began. One phrase: The wiring. The wiring scheme seemed easy enough but it was where the trouble of getting this unit back into operation began. Next weeks blog will be on the difficulties of wiring the up the basic function of the Silvia espresso machine.

The Old Wwworld Cafe
~Dan

Quest for the best espresso Pt. 2

Once everything was disassembled, I had a good idea how all the parts worked together. Next was the fun part. I got to design all the extras that I wanted to to have in addition to the normal function of an espresso machine. The only thing that limited the imagination was physics and the budget, so I decided to design a three phase system to separate the major jobs of an espresso machine. I designed a specially heated reservoir to feed a finely controlled hot water boiler for the espresso shot and a secondary boiler for isolated steam production so that both functions can be run without interfering or adding wait time to heat or cool the system. Implementing these designs would be the tricky part.

With David Schomer's ideal espresso machine in mind, I started by adding the first of three PIDs to the Rancilio, which is a common enough mod. RTD rather then a thermocouple This provides the +/- 1 degree control and instant water temperature read out that I needed for this project. I also knew I wanted to be able to see the pressure within the Boiler to be able to adjust the overpressure valve to allow the pressure to be constant throughout the entire shot. A short time and a few bucks later, and two pressure gauges solved that.
Stay tuned for next week as I continue to unveil each step taken to making this machine reach its full potential!
~Daniel

Quest for the best espresso Pt. 1

Happy Monday to you all! I will be taking the blog from Luke for a couple of Monday entry to detail the transformation of a common household Rancilio Silvia into a double boiler machine. This all started when Luke and I were reading David Schomer's book. We have always approached our coffee with the strictest of procedures, but when it comes to espresso the tolerance for error is practically non existent. Our goal was to create a machine that could be used at home or in a small commercial environment, and to do it on the cheap. At the end of all of this you will see our total cost for all the parts, but for starters the Rancilio cost about $350 used.

Once we got to looking around at the machine we realized something, espresso machines are far less complicated then most people would like to think. The whole machine can be broken down into 3 parts: the pump, the boiler, and the head group. So staying true to the tinkerer ways, the next step was to totally disassemble the Rancilio and make it better, faster, stro.... hehe, sorry wrong project...


The Rancilio Silvia espresso machine is commonly modded (granted its usually minor mods), so we did the first thing that every modder does at the start and voided the warranty.

With the pieces that were in front of us, we were able to start planning the extras that were going to be added, how all the wiring and plumbing was going to work out, and how not to turn this pressurized boiler into a steam bomb(editors note: I was not happy about the odds I was given that my garage may have a hole in it, so caution, do not try this at home!!). After having all of this layed out in front of us, we knew that this was going to be an exciting project.



Stay tuned for week two as the project comes together, wrong parts come in, and circuits are broken!

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