New Piston finished

After many stops and starts, successes and failures, I have a functioning piston.





The results are great, especially after I stopped using a Pavoni-style preinfusion and changed to a ~2 second ramp up to full pressure. I'm getting more and more pleasant flavors out of the Yunnan beans, but I'm looking forward to two Italian-style espresso blends which I'll be getting from Arabica Roasters (in Beijing) soon. (arabicaroasters.com)

Bottomless Portafilter!

Courtesy of Les of Thor Tampers, I now have a bottomless PF.

I'll let pictures do the talkin'

The first modification

Unfortunately this was not on the list of planned mods, rather it was necessitated by a mistake I made when having the broken upper arms welded together.

The first time they were repaired there was no problem. After a couple of days one of the arms broke again and I went back to have it fixed. The welding process went like this: I would hold the two parts together with my hands while the young man welded two spots on opposite corners of the break. With the seam set like this he continued to weld more material around the entire seam.

When I was holding the two parts I did not pay careful enough attention to their alignment, and when I got home and tried to re-assemble the Presso I found that I had not held them together correctly! The hole where the two upper arms meet the piston was way out of alignment and the screw would not fit together.

At first I thought it was the extra welded-on material getting in the way, but filing it down didn't help. I then noticed the strange angle where the two arms meet.

I considered taking it back to be broken and welded again, but decided instead to trim the plastic chamber and piston 'rod'. This works fairly well as you can see below.



Next I will write about a modification that actually improved the Presso . . .

Modifications

I have many ideas for modifications, and have managed to carry out exactly one of them, which in fact was not my idea, and I later found to be unnecessary.

Well heck!

Others-

Hole to pour water directly into the chamber, bypassing the piston head.

Heating wire (rope) around the thickest part. (120 watt 24")

Lower dispersion screen.