A Tail about Silvia

Yes, Miss Silvia now has a tail. A chrome tail ending with a PID to boot. If you aren't sure what I'm talking about, that's OK, this page is more for the coffee obsessives who like to tinker with their toys.....

I didn't plan on a full on step-by-step manual for PIDing your Silvia. There are plenty of sites that do that really well... follow any of these links below:

 

http://my.execpc.com/~n9zes/pepesilvia/pepesilvia.html

http://my.execpc.com/~n9zes/silvia/silvia.html

http://home.flash.net/~jfmurphy/pidsilvia/

http://www.quiknet.com/~frcn/Coffee/Coffee.html

 

After a full year of temperature surfing I thought it time to see what all this PIDing talk was about. Actually I had thought about doing it a year ago... it just all seemed too hard. Well it's not really...
Using posts in AC and the above websites as my references I was able to knock off the installation in about 6 hours... Gathering and sourcing the parts took a couple of months. The wiring is standard with the PID wired to the main power switch of Silvia, but my real conundrum was what to do with the box. Hang it on the side? Mount it to the wooden base that Silvia sits on? Flush-fit it into Silvia? ...
By and far, I think the "Pepe" flush-fit is the most elegant, but the amount of skill required and (more of a concern) the irreversible nature of the installation put me in a cold sweat whenever I thought about it. I'm sure Silvia would have felt the same way if she saw me coming at her with a power drill and blunt hacksaw blade.

So I was resolved not to do major surgery, but I didn't want to be limited to having to pick where to hang a project box with PID before I knew where I really wanted it. Something that was moveable would be great. Then I could decide where I liked it the most and fix it. So the moveable idea formed into a solution in itself. What I wanted was one of those flexi lamp necks.... Goosenecks as I finally found out what they were generally referred to as. Better still, once I found out the name, I found the part was readily and cheaply available from most electronics stores as Mic stand extensions. I went with a 330mm length because I wanted my PID toward the back and out of the way of any splashing. There's a large variety of lengths, but generally they end with a 5/8” - 27 male and female thread. This seems to be a "standard" thread dimension... but only with electronics components, mic fittings, antenna’s etc... ask anybody else for a 5/8” - 27 nut and you'll get blank faces...

The internal diameter of the Goosenecks vary depending on manufacturer. I found some with meagre 4mm ID’s, the one I settled on had a 9mm ID.
The wiring through the gooseneck was still a squeeze... and it would have helped if I had realised before I did the shrink-wrapping that it was pointless to run a separate earth to the PID since there was no terminal for it. Geeze... So yeah ran three 10Amp rated wires for power, then two thinner general purpose wires for the controller to SSR and of course the paired thermocouple wire which was already sheathed together in fibregrass. This was about the thickness of one of the 10Amp strands. All strands including the Thermocouple wire were 1m long. This ended up being only just long enough to allow for loose bends. Held it all together with some double walled shrinkwrap. This stuff is really cool. As it heats up an inner lining of clear silicon-like rubber melts around the wires then sets, but is still really flexible.

More of a squeeze was the housing for the PID. A die-cast project box 30mmX60mmX110mm. This is only barely larger than the Fuji PXR3 (24mmX48mmX97mm)... very tight fit. My primary concern was ventilation, but I found the PID seems to run cool. No where near the maximum operating specs of 50 Degree C, so didn't have to cut any vent slots thankfully.


The 40Amp SSR was fixed in the typical spot. One end mounted on the M4 screw protruding from the chassis just above the driptray and to the right of the 3-way solenoid. The other with an M4 screw in a new hole drilled into Miss Silvia... eek. Added some heat transfer compound just to be safe.

Thermocouple was mounted under the left Brew thermostat screw. The thermocouple I first tried to order was from TTI Global. But they are knocking back overseas credit card orders due to fraud... not me!!.. somebody else ....So I had to source one locally (IPA, Industrial Pyrometers Australia). Luckily wasn't expensive to have one made up, and better still they were able to supply me with my SSR too! The mounting block is not your typical washer style thermocouple and because of the extra thickness I had to replace the original screw with a longer stainless one. It’s an M3 for note. Again more heat transfer goop, which seems to get everywhere.

Another cool thing about the installation was that I was able to maintain my old digital thermometer (from temp surfing days) running parallel to the PID to check that temps were in fact what the PID was saying. I removed this finally after a few days and re-instated the Rancilio badge on the front of Miss Silvia.

The only visible cut I had to make to Silvia was a hole in her backside!!.... Yikes.. we both almost fainted.. I figured if things went really bad and the whole idea of Silvia with a Tail sucked I could fit a rubber grommet in the hole and run the original power cord through it. Thought it was a good backup plan.
As it happens, I really like the “PID in a Tail” concept (“Silvia Sentinel” or “Goosed up Silvia” if you prefer) . Functional and a bit industrial looking. Kinda like Silvia. Oops hope she didn't hear that....
*** Warning ***  I’m sure the above project is a death trap, and electrocution is most likely. Come on.. All metal casing, flexing wires, rubbing on rough unfinished metal, splashed water finding it’s way to live connections .... Please take note if you plan a similar installation.
 
 
 

Added Tidbits

There seems to be a bit more interest in this design than I anticipated. So have added just a couple of extra notes.

For a nice clean hole in the base frame of Silvia (and PID enclosure), I started with a pilot hole, then up to a 10mm drill, then finally used a 3/4" grinding attachment. I didn't go all the way in or the hole would be too big. **You may notice in the above pic I had to chop the screw dropping through the chassis from below the water reservoir.

I ended up using the male end of the gooseneck at the Silvia base and female end at the PID enclosure. This is reverse to what I first intended.

The benefit was twofold.

1. Having the female end at the PID gave me more room for the wiring.

2. Using a chopped down gooseneck mounting base epoxied to the inside of the PID enclosure helped strengthen the VERY thin aluminium casing.

*** Lastly...there's lots of room in Silvia (if not already taken up by other mods.). I could have easliy installed a 24V DC adaptor. Then run 24V DC through the gooseneck to power the PID. This would only apply to a PXR3. Would need to check specs on other PIDs.