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Gaggia Classic - Portafilter Pressure Gauge - OPV mod

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I got around to making a pressure gauge for my Classic.

 

I was looking for the parts to make it and found an ebay seller that had everything I needed - cpmpneumatics. It turned out the seller was only a couple of miles away so I called in and picked them up.

 

Anyway I thought I'd post the details so anyone can order them and make their own. The only extra you'll need is some PTFE tape to seal the threads. I only needed it on the portafilter.

 

Please note: This assumes your PF thread is 3/8" BSP

 

Pressure Gauge

Reducing Bush

 

If you need PTFE tape they even do that

 

PTFE Tape

 

Here is the finished article.

attachment.php?attachmentid=1164&d=1336677782


Home - Quickmill Veloce Prototype with IMS Shower | EK43 | Torr Blackwood Trapez Goldfinger | IMS 22g Basket

Work - Quickmill Andreja Premium | Nuova Simonelli Oscar | Gaggia Classic DIY PID mod with Rancilio Silvia Steam Wand

Work - Mazzer Super Jolly (Doser) | Anfim Super Best | VST 18g Basket | Torr Black Metal Goldfinger handle with Standard Flat base

Brewed - OE Lido | Porlex Mini | Aeropress | V60-01 | Chemex 10 cup

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Thanks so much for this. Saved me the embarrassment of having to explain to the local plumbers merchant what I am trying to do.

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Thats great.. just what I have been after! Best bit is the price!

Many thanks!

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Just a thought... have you considered adding a ball valve to the setup, which would allow you to let water flow out at a rate simulating an espresso shot?

 

I have thought about this quite a bit and have done a bit of digging on the interweb. I was trying to get to the source of the 10bar static pressure = 9 bar brew pressure myth.

 

A ball valve apparently is not the best option as it is difficult to control flow, but needle valves are a little pricey. Some have suggested open the steam valve which is something I am going to try. Others say it is almost impossible to replicate the espresso shot in any case and it is best to experiment with various static readings and choose which tastes best.


Home - Quickmill Veloce Prototype with IMS Shower | EK43 | Torr Blackwood Trapez Goldfinger | IMS 22g Basket

Work - Quickmill Andreja Premium | Nuova Simonelli Oscar | Gaggia Classic DIY PID mod with Rancilio Silvia Steam Wand

Work - Mazzer Super Jolly (Doser) | Anfim Super Best | VST 18g Basket | Torr Black Metal Goldfinger handle with Standard Flat base

Brewed - OE Lido | Porlex Mini | Aeropress | V60-01 | Chemex 10 cup

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I have tried the steam valve method and there is no more than 0.4 bar difference (disclaimer: on my machine). I cracked a leak on the portafilter gauge itself at about the same flow rate, just to check it mattered where the pressure relief was located, but it made near as darn no difference.

 

I adjusted down to just below 9 bar. First shot was a choker so dialled the grind a bit coarser. Second shot definitely was about right (40g from 18g in 25secs) and there was no doubt a LOT more crema, but it looks and tastes a little over extracted. Still good, but certainly leaning that way. I have found that pressure does have quite an effect on temp surfing, so will have a play and make sure I'm not runing too hot.


Home - Quickmill Veloce Prototype with IMS Shower | EK43 | Torr Blackwood Trapez Goldfinger | IMS 22g Basket

Work - Quickmill Andreja Premium | Nuova Simonelli Oscar | Gaggia Classic DIY PID mod with Rancilio Silvia Steam Wand

Work - Mazzer Super Jolly (Doser) | Anfim Super Best | VST 18g Basket | Torr Black Metal Goldfinger handle with Standard Flat base

Brewed - OE Lido | Porlex Mini | Aeropress | V60-01 | Chemex 10 cup

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This is great - will also be ordering!

 

Now any suggestions on how best to remove the PF spout without a vice? Haven't tried it, but I imagine it's stuck pretty tight...


Rancilio S24 - Mazzer SJ

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He he. That is by far the hardest part of the exercise. It has some loctite on it or similar.

 

I don't have a vice. I found a screwdriver that fit through the spout. I felt sure I was going to snap it on a number of occasions.

It was not a case of cracking the glue and wind it off either. It took several turns before it got any easier and several times I feared it was stuck solid, I couldn't even wind it back. Anyway perseverance go me there in the end.

 

It would be a lot easier with a vice ;)


Home - Quickmill Veloce Prototype with IMS Shower | EK43 | Torr Blackwood Trapez Goldfinger | IMS 22g Basket

Work - Quickmill Andreja Premium | Nuova Simonelli Oscar | Gaggia Classic DIY PID mod with Rancilio Silvia Steam Wand

Work - Mazzer Super Jolly (Doser) | Anfim Super Best | VST 18g Basket | Torr Black Metal Goldfinger handle with Standard Flat base

Brewed - OE Lido | Porlex Mini | Aeropress | V60-01 | Chemex 10 cup

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Hmmmm. My poky East London flat doesn't allow for a workshop unfortunately. Maybe I'll invest a few quid in one of those mini table vices...


Rancilio S24 - Mazzer SJ

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A screwdriver will damage the surface of your spout!

 

Take a hammer and a piece of wood. Lay the wood on one side of the spout and tap with the hammer.

 

It will budge :)

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A screwdriver will damage the surface of your spout!

 

Take a hammer and a piece of wood. Lay the wood on one side of the spout and tap with the hammer.

 

It will budge :)

 

Lol I hate to think what you thought I meant to do with the screwdriver. You pass it through the hole in the spout it should be a nice tight fit thus giving you good purchase to unscrew the spouts no chance of damaging the surface or squashing the spouts

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Quick thing, if its locktite or something like it, one thing that may make it a bit soft & easier to undo would be Acetone (nail polish remover) as it dissolves some of the adhesive, It works on superglue to.

Edited by RobD

Quick mill Verona, Eureka Mignon, 17 & 21gLM VST plus other stuff, even get a half decent coffee out of it sometimes :D

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Oh my poor suffering Classic. Hammers, acetone, screwdrivers, lumps of wood...

 

I had to use an extending wheel nut wrench to get inside the OPV!


Rancilio S24 - Mazzer SJ

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Oooh definitely a +1 for the company recommended for parts. I ordered yesterday afternoon and have just received my gauge at work!


Rancilio S24 - Mazzer SJ

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Just did the mod. Improvised by putting the round handle of a can opener through the spout and bashing it with a hammer until the loctite came off.

 

My Classic was running at TWELVE BAR. Got it down to just over 9 in two attempts.

 

Thanks everyone for your help. This is a great forum!


Rancilio S24 - Mazzer SJ

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Tribs

Thanks for the links my gauge arrived today and i have just done the mod. My classic went off the gauge so above 13bar adjusted now to 10bar what a difference it makes

MRH

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I've ordered the parts for one - thought it would be nice to have one less thing to think about!

 

Edit: I also wanted to know whether it's possible to preinfuse by opening the steam valve so I'm going to see what effect that has on the brew pressure too.

Edited by lookseehear

Roy & Alex & The Maestro & Herman ze Hausgrind

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So my gauge parts arrived today - turns out my opv valve was set at 14 bar! I had guessed it might be a bit high as I'd been having quite a lot of channelling and had to grind really fine to slow the flow down.

 

I really think anyone with a classic that isn't using pods should do this mod.

 

Also, opening the valve on the steam wand does work for pre infusion - with the gauge attached and pump running you can effectively pressure profile with a bit of a twist of the steam knob. Not something I'm that bothered about at the moment but interesting none the less.


Roy & Alex & The Maestro & Herman ze Hausgrind

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Great thread, might have to have a go at this.

How do you adjust the pressure?


Espresso: Quick Mill Verona

Grinder: Mythos and loving it

Tampers: Reg Barber flat 58.35

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There's a guide in the technical / faults / how to section of the forum. It was quite easy although mine was a bit stubborn at first.


Roy & Alex & The Maestro & Herman ze Hausgrind

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Now I have done the mod I'm happy to lend my gauge around to forum members. I'd like it back at some point but if anyone is interested then post up.

 

I know they're pretty cheap but once the adjustment is done its just going to be sat on my shelf. If the demand is anything like last time a gauge was sent around then we can come up with a system. Otherwise just £2 via PayPal to cover postage is fine with me. I'd rather it isn't just totally random people from the internets so I'll put an arbitrary limit of 10 genuine posts to be able to borrow.

 

List:

1. Jason1wood - done

2. Obsy - has gauge

3. Oldman

4. MartinB

Edited by lookseehear

Roy & Alex & The Maestro & Herman ze Hausgrind

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I'd like to borrow it mate. Just PM me how to send payment. Many thanks.


Espresso: Quick Mill Verona

Grinder: Mythos and loving it

Tampers: Reg Barber flat 58.35

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Fab idea - I'd appreciate being added to the list.


Gaggia Classic (Silvia Wand) | Eureka Mignon | 58mm Reg Barber 'Hasbean' Tamper | Aeropress |CCD| French Press

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