# DIY thermofilter build/ideas



## Jim bean

Hi I've just finished fitting a PID to my classic and want to make a thermofilter using a single basket JB weld flow restrictor and thermocouple

a couple of ideas I've found

Using single basket, JB weld, thermocouple in centre of the basket

http://www.gaggiausersgroup.com/index.php?action=ezportal;sa=page;p=91

See Rick bonds post about upgrading the scace using a sintered bronze filter/needle valve + gauze filter to stop coffee grinds

http://www.home-barista.com/levers/londinium-i-unstable-brew-temperature-t25444-600.html

using a 1/32" pinhole restrictor

http://s1cafe.com/viewtopic.php?f=58&t=1366

i think I will use the the GUG method with JB weld but replace the guitar string with a flow restrictor

I'm not sure if the 1/32" pinhole restrictor has adjustable flow but sounds like the

sintered bronze filter/needle valve does

http://www.ebay.co.uk/itm/190847338559?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

would any one know what type of needle valve would be needed to fit this?

This is the thermometer I'm using

http://www.ebay.co.uk/itm/Dual-Two-Channel-2-K-Type-Digital-Thermometer-Thermocouple-Sensor-1300-C-2372-F-/270887344801?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f1224daa1

I will keep updated as I go any ideas or suggestion welcomed

Thanks James


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## MooMaa

Hi,

I also have been looking at this kind of project, to measure the brew-head temp on my classic.

I have been reading the same pages as you and will be putting something together using almost the same components. The adjustable pinhole flow valve is the one component I have been having trouble locating. I will have a go with the sintered valve you mention, but do you need another part or does this one act as a needle valve with the underneath screw adjusting the flow rate?

Anyway cant wait to see you progress this project.


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## Jim bean

Hi MooMaa thanks for bringing this up as I've just realised the eBay linked sintered filter looks exactly the same as Rick bonds in the home barista link

i thought the eBay one needed a added needle valve which had a hole in the bottom but maybe it works buy the water dribbling out the more you loosen the screw going by Ron's description ("the outflow drips down gently instead of spraying a fine mist of water over everything")

anyone know what size gauze would be best for stoping way ward coffee grinds?

just seen this might be better from the UK too

http://www.airlines-pneumatics.co.uk/product.asp?ProductCode=S010194&prod=hand_adjustable_throttle_silencer

cheers James


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## Jim bean

A little update I went to a hydraulics supplier explained what I needed to do and they came up with

this its rated up to 10bar but said it should be good for double that and has adjustable flow plus the water should just flow out the bottom doesn't look pretty but as long as it gets the job done


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## MrShades

Needle valve Jim? Looks good... can't wait to see the end result.

I've got a similar thing on order (from China!) and with a T-piece and my pressure gauge I'm hoping to do a similar thing for pressure (ie pressure when there's a small trickle of flow).


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## majnu

James what diameter is the orifice at the end of the valve?


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## MrShades

As luck would have it:



















10 bar static does indeed appear to be 9 bar dynamic.


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## Jim bean

Hi Mrshades forgot to ask what it's called I'll give them a call to find out but it's adjustable from no flow to fully open which should be more than 56ml in 30 seconds

hi majnu the exit hole for the water is 9mm the part that fits in to the portafilter is 1/4" BSPP fitting

cheers james


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## Jim bean

That looks just the ticket Mrshades even better with the pressure gauge fitted I assume it would be just as easy to attach it to a basket for use with a naked portafilter

have you got a link please

cheers James


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## MrShades

Needle valve: http://www.ebay.co.uk/itm/311111947240?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

T-piece: http://www.ebay.co.uk/itm/111273838765?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

...and for the sake of completeness:

Pressure gauge: http://www.ebay.co.uk/itm/120873578223?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


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## MrShades

...now just got to fathom out how to get a thermocouple in there as well... ;-)


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## DavecUK

You might want to think about using an NTC thermistor bead and resistance meter (if one with a 9V battery choose a 100K probe, with lower voltage batteries you can choose lower resistance ones...there is a chart out there somewhere). These can be very fast acting and quite accurate over the smaller temperature ranges. e.g. one that goes up to 125C or even 240C. Choosing a higher restistance will make heting due to measurement voltage negligible but of course the conductivity of liquid then has a larger effect....however the leads can be coated to help minimise this.

The beads themselves can be had very cheaply and many times I have thought of converting my own device to use an NTC thermistor and my accurate multimeter.


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## majnu

Jim bean said:


> Hi Mrshades forgot to ask what it's called I'll give them a call to find out but it's adjustable from no flow to fully open which should be more than 56ml in 30 seconds
> 
> hi majnu the exit hole for the water is 9mm the part that fits in to the portafilter is 1/4" BSPP fitting
> 
> cheers james


9mm, you sure? That's huge.

Does anyone know a UK company who makes precision orifices like these?

http://www.okcc.com/PDF/cat%2011%20Rev%207%2B_web.pdf


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## Jim bean

Hi Dave thanks for that would it be as simple as something like this connected to the 2 pronged terminal on thermocouples that fit the thermometer/multimeter?

http://www.ebay.co.uk/itm/100K6A372I-Betatherm-Thermistor-NTC-/141350299047?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item20e92265a7

Hi majnu the valve is in the middle of the fitting controlled by the locking screw the 9mm exit hole is a universal fitting but I'm leaving it blank so the water can just flow out the end

it's fully adjustable so I could tighten the locking screw all the way and no water would come out

cheers james


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## DavecUK

Jim bean said:


> Hi Dave thanks for that would it be as simple as something like this connected to the 2 pronged terminal on thermocouples that fit the thermometer/multimeter?
> 
> http://www.ebay.co.uk/itm/100K6A372I-Betatherm-Thermistor-NTC-/141350299047?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item20e92265a7


That sort of thing, but with a bigger range either up to 125C or 240C, ensuring that it's OK with water. There are some bead ones like 5 or 10 for a few pounds, they simply have bare wires on them. They won't work in the K type thermocouple slots of a temperature meter, these need an ohmmeter (multimeter), depending on the batter in the multimeter, determines the resistance level of the thermistor. e.g. if you mutlimeter uses a 9V batter or a 1.5V battery. You also need the right tolerance e.g. 5% or less if you can. Have a quick read of the document below to bring yourself up to speed.

http://www.avx.com/docs/masterpubs/ntctherm.pdf

You will also need the resistance conversion charts, so you know what resistance (ohms) = what temp in C

However they are very fast acting and can be quite accurate over the smaller range of temps in espresso machines...unlike the thermocouple which can have relatively large errors in a small range e.g. 1C in a range of -100 to +700C may be very small, but it's a lot when in the 0-100C range.

or you could use the more expensive, but far more accurate resistance probe, PTD or RTD sensors.


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## Jim bean

Thanks Dave the PT100 option sounds good I think you could get a probe and meter for around £15 there does seem to be a lot of variables with trying to simulate and measure the brew temp as long as I get in the ball park at least there's a starting point

cheers James


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## DavecUK

Jim bean said:


> Thanks Dave the PT100 option sounds good I think you could get a probe and meter for around £15 there does seem to be a lot of variables with trying to simulate and measure the brew temp as long as I get in the ball park at least there's a starting point
> 
> cheers James


Wow, I'd be interested to know where one can be had for that....do you have a link?


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## Jim bean

Hi Dave these are the ones I was looking at

meter

http://www.ebay.co.uk/itm/Digital-DC-Temperature-Meter-for-RTD-PT100-Temperature-Sensors-C-12VDC-/251160356231?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3a7a52e587

probe

http://www.ebay.co.uk/itm/P4PM-1m-High-Temperature-Cable-PT100-RTD-with-6mm-Thread-Thermometer-sensor-/301195422486?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item4620a56b16

Cheers James


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## majnu

Jim bean said:


> Hi Dave these are the ones I was looking at
> 
> meter
> 
> http://www.ebay.co.uk/itm/Digital-DC-Temperature-Meter-for-RTD-PT100-Temperature-Sensors-C-12VDC-/251160356231?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3a7a52e587
> 
> probe
> 
> http://www.ebay.co.uk/itm/P4PM-1m-High-Temperature-Cable-PT100-RTD-with-6mm-Thread-Thermometer-sensor-/301195422486?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item4620a56b16
> 
> Cheers James


Resolution looks bad on that going by the pic. You'd need atleast 0.1. Just thinking out loud why not just get a 1/32" PID to display the temp? You'd probably want to be able to quick disconnect the probe otherwise it will always be attached to the DIY thermofilter.


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## Jim bean

PID would definitely be the cheapest option it would need wiring to the mains I think I'll stick with the thermometer idea as it's battery operated and I've got it sitting here

i might change the thermocouple for a teflon or ptfe coated one just to stop the moisture creeping up the sheath


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## DavecUK

Jim bean said:


> Hi Dave these are the ones I was looking at
> 
> meter
> 
> http://www.ebay.co.uk/itm/Digital-DC-Temperature-Meter-for-RTD-PT100-Temperature-Sensors-C-12VDC-/251160356231?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3a7a52e587
> 
> probe
> 
> http://www.ebay.co.uk/itm/P4PM-1m-High-Temperature-Cable-PT100-RTD-with-6mm-Thread-Thermometer-sensor-/301195422486?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item4620a56b16
> 
> Cheers James


The accuracy of the powered diital meter is only +/-1C, so that's not enough and I would do better using my old BT Multimeter.

The Pt100 probe is also quite slow with a response time of 2 seconds...which is again a bit sluggish...it might work OK with a multimeter though...certainly can thread or bolt it into a portafilter?


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## majnu

Why do some pressure guages appear to be filled with water? Is that why you have what appears to be a valve to drain water?


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## majnu

majnu said:


> 9mm, you sure? That's huge.
> 
> Does anyone know a UK company who makes precision orifices like these?
> 
> http://www.okcc.com/PDF/cat%2011%20Rev%207%2B_web.pdf


Answering my own question here for sake of completeness but I found a company today and I've fired of an email.

http://www.westgroup.co.uk/wp/wp-content/uploads/2014/10/Ruby_Sapphire_Precision_Orifices.pdf


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## Norvin

For what its worth.

Carburetter jets are precision orifices.

If you mounted a jet holder in the portafilter, it would be an easy matter to swap jets to adjust flow rate.

They are generally numbered to specify the amount of fluid they will pass at atmospheric pressure, (well, Amal jets are), the larger the number the more fluid will pass.

Carbs are old technology now, but a number of restorers and racers of classic machinery will have a range of jets to allow tuning of individual machines.

Ive got a tin of jets in the garage, but not a full range, if you want to borrow some, although they may not be in the range that you need.


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## El carajillo

There is a blast from the past "AMAL CARBS"


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## majnu

majnu said:


> Answering my own question here for sake of completeness but I found a company today and I've fired of an email.
> 
> http://www.westgroup.co.uk/wp/wp-content/uploads/2014/10/Ruby_Sapphire_Precision_Orifices.pdf


They don't deal with small qualities unfortunately as they said the price would be too high (They didn't even give a price anyway). Pretty much pissed off now so I'm putting this on the back burner for now.


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## Jim bean

Hi majnu I got mine from here http://www.northwesthydraulicsltd.co.uk they have a trade counter in Trafford park I took my naked portafiter in with a picture on my phone of the scace device and they came up with a few different options cost was £10 all in

Cheers James


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## majnu

Jim bean said:


> Hi majnu I got mine from here http://www.northwesthydraulicsltd.co.uk they have a trade counter in Trafford park I took my naked portafiter in with a picture on my phone of the scace device and they came up with a few different options cost was £10 all in
> 
> Cheers James


Excellent, thank you


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## Jim bean

A little update I've stripped some the outer sheath of the thermocouple and put some extra shrink tubing in the hope it will slow any water pushing up the sheath i drilled a hole in the side of a single basket for the thermocouple then filled with JB weld I heated the JB weld with a hair dryer for 4/5 seconds which made it more workable I will give it a try tonight

Cheers james


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## majnu

Has it properly cured now. Will be interested in water temp during shot vs set value on the pid. Any chance of a sneaky video too showing the thermofilter in action?


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## Jim bean

Hi majnu I've done a couple of videos 1 normal and 1 with 3 second steam blip I've not had loads of time to have a good play around yet but seems to work ok

  

with 3 seconds steam

  

Cheers james


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## majnu

Pretty much perfect using the steam blip method.









I guess if you want to get it bang on you could try expirementing with the steam on and wait times. How is the flow with the orifice you bought? Groovy music too.


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## Jim bean

Hi majnu yeah the steam blip seems to work the flow rate is adjustable so is easy to tweak to what ever ml per second is needed

its seems a good little tool for the cost involved

cheers james


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## majnu

James

A great experiment when you have time would be

How quickly the PID reaches and stabalizes at SV and what the water temp is with a brass dispersion plate vs Aluminium. Or did you already have a Brass one installed in this video?


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## Jim bean

Hi majnu good shout I will give it a go when I get it back I've lent it out at the moment I will put it up for a pay it forward though if you want first dibs

I realise it's a bit fragile so might not get round loads of members but there cheap to make so no big deal

Cheers James


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## majnu

Jim bean said:


> Hi majnu good shout I will give it a go when I get it back I've lent it out at the moment I will put it up for a pay it forward though if you want first dibs
> 
> I realise it's a bit fragile so might not get round loads of members but there cheap to make so no big deal
> 
> Cheers James


Thanks

I've been meaning to make one, but wanted it to look similar to the Scace with the same orifice, T Type Thermocouple and filter with an added pressure gauge also. I've been let down by the orifice supplier who said it will be too expensive for one. I have a K Type thermocouple temperature reader already, but wanted the T Type for it's greater accuracy. I'll try and hunt down the parts so it can be a project over Christmas.


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## majnu

James what's that mesh type thing at the bottom at the basket, I assume it's there to stop the JB Weld stuff from seeping through the portafilter holes.


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## gingerneil

This is all very interesting...

Why blip the steam ? Doesn't this just increase the temp of the boiler before running the shot, and then temp then drifts down a little as the water flows and the boiler fills with cooler water? Cant this same thing be achieved by just setting the PID to a few degrees higher ? Maybe 103C to take into account the 7 or so degrees of drop ?

I'd love to setup my PID using one of these - would anyone be willing to offer a 'rental' ?


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## majnu

The steam blip is used to help time the input of heat. If the SV is higher you will need less steam blip, but if you try to eliminate it you will likely start at too high a temperature and still have intrashot drop. Too hot to start and too cold at the end. The video shows minimizing intrashot drop, that occurs because of a timing mismatch of heat, not just because of the amount of heat.

Cold water causes nearly instantaneous cooling while the elements heat the boiler which in turn heat the water. Granted, that is fairly quick, but not instant. The steam blip is timed, and the amount guesstimated to counter the cooling.


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## gingerneil

excellent explanation - thanks.


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## Obnic

majnu said:


> James what's that mesh type thing at the bottom at the basket, I assume it's there to stop the JB Weld stuff from seeping through the portafilter holes.


I think it's just the holes at the bottom of a single portafilter rather than a mesh - unless I'm being daft: a distinct possibility


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## Obnic

Anyone solved dependable calibration of these thermocouples yet?


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## Jim bean

majnu said:


> James what's that mesh type thing at the bottom at the basket, I assume it's there to stop the JB Weld stuff from seeping through the portafilter holes.


Hi majnu It's a single basket so I think it's just the holes from the bottom of the filter but I did put some insulation tape on the outer holes before I poured the JB weld to stop it seeping through just to be safe


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## majnu

Obnic said:


> Anyone solved dependable calibration of these thermocouples yet?


Not without having a proper liquid bath. I'm just going to go by water boiling temp for my area. So correct me if I'm wrong, if water boiling point in Manchester is 99.9/6 degrees (115 to 138 feet above sea level), if my tc reads 103 then it has a +3'ish degree inaccuracy.


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## Jim bean

gingerneil said:


> I'd love to setup my PID using one of these would anyone be willing to offer a 'rental' ?


hi gingerneil you can borrow mine after majnu if interested might be a while though

Cheers James


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## majnu

Jim bean said:


> hi gingerneil you can borrow mine after majnu if interested might be a while though
> 
> Cheers James


James

I needed one urgently for the preinfusion/profiling mod and I didn't know when the current member was going to finish with it so I'm going to pick up my flow regulator on Monday/Tuesday and make one fella.

Feel free to rent to gingerneil.

Cheers


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## gingerneil

Thanks - I'll pm.


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## majnu

I'm getting great thermal stability - It holds at 93.4 degrees Celsius over a 30 second period and dips down to 93.1 at the end. This is with a set value of 101 and a 4 second steam blip and 4 second wait before hitting the brew switch.

Just need a couple of hours spare time to try other set values and if possible what effects the Aluminium shower plate holder has. The thermofilter has been tuned to deliver 2oz of water over a 25-30 second period. I got it set as 27 seconds for 2oz and that's good enough(!), so the flow regulator used in this build does the job very well.









I found if the portafilter isn't locked in tight then water can trickle down the thermocouple sheathing.


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## bronc

I can't decide whether to use a naked portafilter with a blind basket that has been drilled and attached with a flow restrictor and a thermocouple (similar to this: http://www.home-barista.com/forums/userpix/14721_13070013.jpg) or a standard portafilter with a flow restrictor that has been screwed in place of the spouts. I can't figure out how to get the TC inside the portafilter in the second case though. I can't see the photos in the previous posts. Any tips?

I've seen this but I don't want to make a hole in my portafilter


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