Cheapskate "Scace" Temperature Probe - Page 2

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#11: Post by HB »

There's also Susan's JB Weld and guitar wire technique: Building a DIY Thermofilter.

Dan Kehn


#12: Post by jpender »

I like the guitar string and JB Weld idea. I used magnet wire for a short-lived temperature probe (for live pucks). Magnet wire has a thin non-conductive coating and it comes in a variety of sizes, including thin enough to snake through a portafilter basket hole.

There are lots of ways to homebrew a temperature probe. I've got one in my machine 24/7. But I thought that the idea behind the Scace was repeatability. You can confidently compare your numbers with the next guy who is using one. My probe is almost certainly not well calibrated and that's okay with me. But if I wanted something for comparison I'd have to either spend more money or do a lot more work. A boiling point test isn't enough for that.

I think it isn't really a "Scace" if it lacks demonstrable repeatability.

Capuchin Monk (original poster)

#13: Post by Capuchin Monk (original poster) »

HB wrote:There's also Susan's JB Weld and guitar wire technique:
That's the thread that got me going. :)

I sealed the plug end (first picture).

Since JB Weld resin is easier to drill than brass, I may get that jewelry drill bit set and do some experiments. :idea:


#14: Post by Pressino »

Capuchin Monk wrote:Here's a cheapskate "Scace" I made.

Parts are single serve filter basket that came with my old espresso machine which has been collecting dust for years (I don't know anyone who uses it), bulkhead drain fitting from Amazon, small head temperature probe from Amazon and some JB Weld glue. The most challenging part was putting a pinhole at the cap. Even 1/32" diameter drill bit is too big so I has to use a drywall nail and a hammer to punch it. It took many blows to get it. I put a piece of sponge in the shaft to slow down the flow rate little bit and to filter out the stray coffee ground from making its way down to the pinhole and potentially clogging it.
I like your model and will make one. I wonder if there is some other filler medium besides sponge that we can use to slow down the extraction flow to match that of a coffee puck? Maybe fine glass beads that would maintain a fairly consistent rate of flow when matched with a correctly sized exit hole? That would indeed match the consistancy of the Scace. :?:

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#15: Post by pizzaman383 »

Maybe a stack of puck screens?
LMWDP #551
“Taste every shot before adding milk!”

Capuchin Monk (original poster)

#16: Post by Capuchin Monk (original poster) »

Pressino wrote:Maybe fine glass beads that would maintain a fairly consistent rate of flow when matched with a correctly sized exit hole? That would indeed match the consistancy of the Scace. :?:
It's a high pressure condition and even a pinhole has a difficult time restricting the flow. I thought about another layer of metal plate with a pinhole above the bottom cap may be effective but haven't figured out a way to secure it tightly. :?


#17: Post by PeetsFan »

Peppersass wrote:I believe a #80 bit is the correct size to mimic the "standard" espresso flow rate of ~70ml in 30 seconds at 9 BAR, but it's somewhere between difficult and impossible to drill a clean and precise hole by hand with a bit that thin. It probably can be done with a very carefully aligned drill press, though I don't think a typical drill press chuck can securely hold a #80 bit. So it might require securing the bit in something else, like a hand drill designed for use with tiny bits, then securing that in the drill press chuck.
I think the only way to do it is either with a laser, or you purchase a threaded fitting which has precisely the hole size you want. Then you drill a big hole into the portafilter basket and bolt the threaded fitting into it.

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#18: Post by danetrainer »

When I made one 10 years ago I bought several of the brass caps, then I experimented in getting the correct flow rate.

It turned out that the #80 drill hole still flowed too fast, so since it was brass I took a round flat end punch and peened the brass to decrease the hole size.


#19: Post by PeetsFan »

K7 wrote:I did not know they had a thermofilter-only version!
$400? Yikes. It's probably worth it for professional cafe use, but a little too steep for me.
If someone can build and sell one of these for under $100 which I think is doable, I think a lot of home baristas including me would buy one instead of going DIY. Such a handy tool since most machines don't tell you what temp you are brewing at.
How do you build and sell. one for only $100? Sure, if I were building 250,000 or even 50,000, I might be able to do that. But 100 or 200? No way. Each component will cost top dollar. And if I want a temperature display instead of just a temp output for a Fluke meter, then I'd program an FPGA and it would output to a little numeric LED/LCD display. It's inexpensive, but at quantity 100 or 200, DigiKey will charge you $10 here and $15 there and soon your part cost is already $100, plus labor, and shipping, development time, and then returns because somebody says your pinhole is too big, or too small, or the temperature is 1/100000th of a degree wrong, or it's the wrong color... You'd lose money.

Capuchin Monk (original poster)

#20: Post by Capuchin Monk (original poster) »

Or sold in kit form and let the customers assemble it on their own? I've seen consumer audio electronics offered in such form (diy speaker kits).