erics wrote:If your 0-200 psi gage is not oil filled, you will be disappointed with the dramatic needle flutter

Here is a video showing a home made pressure gauge using an AIR pressure gauge, with no significant needle bounce.




...split from Still haven't hit espresso nirvana by moderator...

2 sweaner: Am I reading it correctly from your video? 15 bars of pressure? Is not it too much?I would say 9 or 9,5 would be much better. Or there is some rationale behind your high pressure? Thank you.

Vad, I did not make that video. However, just tonight I made a gauge from a $3 air pressure gauge and $6 of parts from Home Depot. It seems to work and may be accurate. No needle bounce, but it does get some fog in the gauge. Maybe someday Dave will bring his Scace back and we can compare?

OK, so we have swayed a little OT here - my apologies to the OP.

Yes, I surely agree that there does not seem to be much needle flutter on the Utube video but if you check out the other videos that same contributor uploaded to Utube, you'll see that he partially disassembled and tested his "Ebay gage". In addition to the multiple coils of tubing and dedicated snubbers, some gage manufacturers machine an internal thread in the pressure connection to receive a very tiny orifice - if you will - a gage gicleur. Oftentimes, the end user never even knows its there unless you specifically look for it. My singular espresso machine experience with a gage like this is less than desirable - the gage was on a piece of test equipment I had purchased. I would not purchase such a gage although I sure other users may have better results.

When you look at the linked video, you'll also see that he used a simple pipe ell and NPT locknut to mount his gage onto a blind filter. That is a MISTAKE. The locknut will do some damage to the dispersion screen because blind filter housings simply don't have the necessary depth. A "more better" option would have been to use a singles basket and pour in some Loctite epoxy or perhaps potting compound. The Pasquini Livia 90 he is testing was built by Bezzera and the hydraulics of those machines (I BELIEVE) make the differential between blind filter pressure and typical shot pressure substantial. That subject is discussed in more detail here - http://www.home-barista.com/espresso-machines/why-difference-in-pressure-between-blind-filter-and-brewing-t10807.html

Putting together a $10-15 gage assembly is an achievement but really should be relegated to the lesser expensive espresso machines that have no gages at all. For sure, there is SOME confidence if the homemade gage and the machine's gage both read 130 psi with a blind filter but I would opt for a gage that has a pedigree and seeing as though the oil-filled gage that I previously linked to costs about $2.50 more than the unfilled gage, the choice is somewhat obvious. Gage flutter on a machine equipped with a rotary pump is almost non-existant whereas in my experience, a vibration pump can render a PF mounted pressure gage useless.

A loaner Vetrano in da basement - about a year or so ago - no visible flutter
using an unfilled, calibrated gage in the grouphead

erics wrote:Gage flutter on a machine equipped with a rotary pump is almost non-existant

Ehm, what? Maybe my gage is busted, or maybe it's a bad pump, but I've got a lock-stock Astoria Argenta SAE II (RG) with a lock stock Procon pump, motor, and Orban gage, and the needle bounces around like a one-legged single guy at a wedding reception.
Izzat something I should be worried about?

Data point: I helped descale a Synesso Cyncra a couple weeks ago, and after we flushed it and hooked it back up, the gauge was fluttering like mad and was making really irritating noises too. We consulted the user manual, which said that that usually means the capillary line got water in it. We pulled that line, and blew it out with a 2-way vacuum cleaner, re-attached, and it was smooth sailing again. I don't think that rotary pumps are somehow easier on cheap gauges. They still need either capillary tubing or a flow restricting mechanism like Eric described.

Well, there goes the rest of my free Friday... ; >

Thanks, I had come to accept this as normal, and now I'm thinking that it's an easy fix! Wortha shot anyhoo.

I so love this place... Fixed a two year ongoing problem in less than fifteen minutes.