Great. Thanks for the photos!

Mathias

I recently finished making a replacement piston for the Presso. The original hung on for about 5 months of daily use, then started developing several cracks.

The replacement I made works, but has two problems.

The first is that I cut the bottom of the piston to fit perfectly into the bottom of the piston-chamber, but if the alignment is off by a little bit the piston does not go all the way down. I would suggest to anybody making one that they simply lathe the bottom so that it fills most of the space, this way it is not likely to get stuck.

The second problem is that the diameter of the cylinder of PFTE that I was working is a tiny bit smaller then that of the original piston. What this means is that it is possible for the round 'washer' to be forced out of it's slot, sending a gush of water all the way up to the ceiling . . .

For the next one I will definitely use a lathe. I tried sticking it on the end of a power drill and this resulted in awful alignment. I kinda lucked out in that if I turn it in a certain direction the 'washer' does not get spit out while under pressure.

Here's a picture-



Henry

I'd like to weigh in with my story about broken arms. I bought one of these a couple of years ago and was disappointed with the lack of crema and other problems with it's performance so I attempted to "boost" the extraction pressure by grinding the beans a bit finer. The result was a big surprise! Hot water and coffee grounds in MY FACE and all over the kitchen. The piston hit the ceiling! Fortunately I was not badly burned, but it could have ended up much worse. Use these machines with caution and don't attempt to obtain pressures that are too high. If anyone needs piston or other parts, let me know!

starry wrote:I'd like to weigh in with my story about broken arms. I bought one of these a couple of years ago and was disappointed with the lack of crema and other problems with it's performance so I attempted to "boost" the extraction pressure by grinding the beans a bit finer. The result was a big surprise! Hot water and coffee grounds in MY FACE and all over the kitchen. The piston hit the ceiling! Fortunately I was not badly burned, but it could have ended up much worse. Use these machines with caution and don't attempt to obtain pressures that are too high. If anyone needs piston or other parts, let me know!

Funny coincidence, I was just about to post some photos of Presso shots 'cause I recently got a new (original) piston.

I had a similar experience when my Presso's arms broke, then again when the piston cracked . . . fortunately both were in the winter and the hot water didn't get to my skin! Recently I've been making only regular doubles (avoiding ristrettos) which flow a bit fast (~25 seconds), I'm hoping the piston will be able to take this amount of strain!

If only the company would update it with a smaller diameter piston ...

Henry

It is interesting to see this thread still going and even more intriguing to see the interest this device has engendered.

While I have no interest in the Presso, I am trying to buy some stainless steel scrap from All Clad whose US office and plant are just ~5 miles down the road form my home in Pittsburgh's south hills. Here is a picture of me at their factory in front of some stainless steel stamping blanks.


Actually, these are stainless steel clad aluminum stamping blanks which must have the aluminum separated from the ss for either scrap material to be of any use. This separation is done by an outside company in Belle Vernon, PA named: Life's Work (http://www.lifesworkwpa.org/). Life's Work provides employment to handicapped persons and is, in my opinion, a most worthwhile effort. The facility uses mentally retarded folk for this work.

Here are a couple of pictures I took at Life's work.


Bravo! All Clad - both for the making the Presso and for giving employment to the folk at Life's Work.

Len

Hey Jim,
That's a brilliant modification. I've tried to fill the air gap in mine by shaving some champagne corks and I probably filled 3/4 of the available space, though I'm still not getting anything like the crema you had in your photos. I find that if I raise the arms, give about 4s preinfusion before pressing firmly that the shot is way short of 20s extraction time. Can you remember any more details of the technique you used with this machine?

I put the assembled pf (and cup) in a warm oven while dumping boiling water through the body before quickly filling the pf and filling the hopper to the "double" line. I've tried lots of ways of raising the arms: just enough to let the water bubble through the valve, raising them fully, even an extra pump or two. The taste is a little sour (not bad for a newbie) but there is precious little crema apart from a few white bubbles at the end.

I'm afraid that I'm still using the pre-ground (espresso roast and grind) that came with the presso but the hand grinder that came in the package looks promising (ceramic conical burrs with quite responsive adjustment). I'm keeping the ground coffee frozen and thawing a small batch each day so that I'm using room temperature coffee in the hot pf.

Did you mean to suggest that you used a naked pf with the presso, or the "naked pf" shot was done with another machine? I'd love to know how to get a naked pf to fit the presso.

Thanks for reading