Londinium piston modification? - Page 2

A haven dedicated to manual espresso machine aficionados.
thebookfreak58

Postby thebookfreak58 » Aug 08, 2018, 10:16 pm

Also have same issues (have Cafelat seals). Have been communicating with Paul in the past about this.

Would be keen to try a new piston for sure!

HoldTheOnions

Postby HoldTheOnions » Aug 08, 2018, 10:42 pm

I think on the L1 you would want to pull the lever for a second or two to release any steam in the hx. If you wanted to post a youtube, then people could probably tell you if it is catching "normally" or not, if you aren't 100% sure.

walt_in_hawaii

Postby walt_in_hawaii » Aug 09, 2018, 12:41 am

Joe, tried to pull the steam lever a second before the shot... I didn't see a difference, sorry.
I don't have access to the social media stuff, so can't look at Paul's pistons :( does anyone have a link they could point me to?

mivanitsky

Postby mivanitsky » Aug 09, 2018, 1:28 am

You don't need an Instagram account. Just Google "Cafelat Instagram."

thebookfreak58

Postby thebookfreak58 » replying to mivanitsky » Aug 09, 2018, 4:34 am


mathof

Postby mathof » Aug 09, 2018, 4:54 am

I have the L1 too, with Reiss's own seals installed. Variations in the height of the point where the lever grabs seem to vary with puck saturation during pre-infusion. A fully saturated puck (beading visible over the whole of the shower screen) gives a grab point of 45° from the horizontal. Otherwise, the grab point is higher.

Matt

Phaedrus

Postby Phaedrus » Aug 09, 2018, 7:34 am

Forgive my ignorance, but wasn't this solved on the L-R by using custom seals? Or is this an issue specifically with the L1? (Asking because I plan on getting an L-R someday)

pizzaman383

Postby pizzaman383 » Aug 09, 2018, 8:03 am

Paul_Pratt wrote:Not really teasing, we made some to test the theory that the current piston design is wrong and it proved to be correct with the testers so far. Replacing the actual piston is quite a tricky process and will require 2 special tools, one of which will only ever be used once and is then useless.

If there is demand I could look into it, but really it is something a manufacturer should be doing.

What change did you make to the piston? What is the problem with the current piston design?
Curtis
LMWDP #551

walt_in_hawaii

Postby walt_in_hawaii » Aug 09, 2018, 1:04 pm

Tim, thanks for the link!
3 rings. Hmm. But (counting from the bottom) the spacing between ring 1 and 2 is slightly wider than stock, spacing the rings farther apart. And the seats of the ring lands do look slightly higher (to push the rings out more), but hard to tell without a micrometer. Also cannot tell piston diameter without micrometer. I know the expansion coefficient of brass is a lot more than aluminum or steel, which is what I normally work with, so tolerance will have to be greater... but given the reported sloppy tolerances in the bosco piston to cylinder groups I've read about, its a given that a custom made one can be made to match the existing cylinder much better, especially since I'd be able to get the cylinder dimensions before I start. I have no idea what is happening near the mounting flange on Paul's design. Is it 2 piece?
But, interestingly, its day 2 with the new cafelat seals, and it's grabbing slightly lower! just a tad, but definitely lower. Now consistently about 10:30, near 45 degrees... I never saw anyone post the 'best' case scenario with the best seals.... no one wanted to come forward with that?

walt_in_hawaii

Postby walt_in_hawaii » Aug 09, 2018, 1:09 pm

mathof wrote:I have the L1 too, with Reiss's own seals installed. Variations in the height of the point where the lever grabs seem to vary with puck saturation during pre-infusion. A fully saturated puck (beading visible over the whole of the shower screen) gives a grab point of 45° from the horizontal. Otherwise, the grab point is higher.

Matt

Thanks Matt. I had the stock seals in mine too, but just changed out to the softer cafelat ones. I could not remove the stock seals... I had to cut them to get them out, by sticking a wooden chopstick underneath a seal to lever it up, then cutting the seal with a razor. It makes sense that stiffer seals will not deform as much, but I like the idea of compliant silicon seals that last much longer. My stock seals were at the end of their useful life and exhibiting some inconsistencies on extraction, and showing small cracks as I flexed them with the chopstick.