Basket $6.95 http://www.espressoparts.com/EPMZ_107A?&search_id=1884565 JB Weld $6.00 Copper $1.50 estimate 0.011” wire $2.00 estimate, or free if guitar playing friend Du-Bro Med Silicone $2.00 Fuel Tubing HDPE Plastic $1.50
About $20 including the basket, not including a temperature sensor or reader. I used a K thermocouple and reader and retested with Polder as in the original post.
Polder thermometer $8.00
I used it in the same test as the first PF with K thermocouple and Polder with similar result.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,191 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Sun Aug 19, 2012, 1:12pm Subject: Re: DIY PortaFilter - ThermoFilter Inexpensive Basket Thermofilter
This basket thermofilter was very easy to make and maintain. I have had it plug once with a coffee ground in the hole. Fairly easy to remove with the original E string wire. Solution is to clean the machine before using the thermofilter. Use a cleaning agent, remove the screen and back flush. I rarely see a left over grind if I clean first.
When I originally made the TF, I lost the wire and hole. I broke off a soft wire in the hole. I had marked the approximate spot and then gently opened the area with a countersink tool. I was able to find the hole and thought all was good. I ran basket in the machine and got 90 ml in 25 seconds and found that a second hole, one over, had blown out from removal of epoxy with the countersink tool. I got the E string and mixed a small JB weld patch and re-epoxied the holes up and the wire in. I then had a 70 ml run in 25 seconds and decided that I had opened the hole with a needle a little too much. I did a third attempt, patched with wire in, and pulled the wire without any attempt to expand the hole and back to 50 ml in 25 seconds. This TF was easy to build, and to correct mistakes.
A K thermocouple and reader can be inexpensive if you don’t mind the order and wait from China, $5.77
Probably NOT good enough for government work, but works well enough for the home user.
I have continued to use the basket thermofilter. No problems and easy to use. This has helped me to adjust and understand the temperature in the Gaggia classic. A little critique. I think that for the expense, lack of, and ease of build it was very worthwhile. I have had a chance to see a few others in action on YouTube and of course found nothing like the real thing, the Scace. Mine and some of the others are slow to respond. I think that ease of build and maintenance came at a little sacrifice of responsiveness. Putting the thermocouple in a copper tube made replacement and other use easy, but blunt the response with added mass and shielding of the thermocouple.
the concept of making the puck of a DIY thermofilter with raw sintered metal beads was proposed. I am not sure of the density/thermal mass of the beads. Epoxy and HDPE are fairly low thermal mass as coffee.
The other problem to face when making a thermofilter is to make it with the correct or variable orifice, and a cleanable orifice. The orifice is in essence a single basket hole and can be clogged with one grain of coffee.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,191 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Tue Mar 26, 2013, 7:57pm Subject: Re: Styrofoam Cup Method
I have decided to add a Styrofoam Cup explanation in this thread dealing with temperature measurements. The photo shows the cup with an instant digital thermometer inserted. You cannot do it well without digital instant. Those are available for about $10 or less. The cup is cut short and to about the diameter of the basket so that it fits in the group. I run the test about 3 - 4 seconds, about 30 - 40 ml. To repeat the test wait about 5 - 10 minutes to re-equilibrate. Be careful, the water should be about 200F and you want it all in the cup, not on you.
In use I preheat the cup and thermometer to about 200F so that it reads very quickly. Just before I run the test I pour hot water in the cup, dump and run the test. If you do not preheat and you wait a couple seconds for the steel probe to heat and conduct, the temperature will be falling as you read it. If you pay attention to detail you can get reasonably reproducible temperatures, though the method still is an approximation.
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 5,655 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Wed Mar 27, 2013, 6:19am Subject: Re: Styrofoam Cup Method
Remember the Scace device was developed by a person in their home/garage. Anything that can regulate the flow to simulate the flow through the coffee and has a thermometer and a way to measure pressure will work, less room for water will help be a bit more accurate with water temp.
I have seen a needle valve used to adjust the flow of water. A naked PF and a back flush disc should be able to be modified to install a pressure gauge, a needle valve and a temp probe. It may not be slick looking but as long as it does not leak, it will get the job done.
In real life, my name is Wayne P.
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