Small oring experiments on my caravel adventure continue...

I now have two working caravels, and one of the lids has a pid probe which works very well.

I recently ordered an incomplete caravel for parts to play with (I want to build the pid into the body and have fantasies about making the tray into a scale).

I measured up the small oring that came with this early version machine and perhaps it is an original seal. It is 1.5mm cross section and 5mm ID.

This is different from the 2mm X 4mm that Francesco and everyone recommends.

Perhaps the small oring shredding problems relates to this. I no longer have big problems with shredding as I probably use lower pull pressures than when I was a beginner. But my orings do still come out badly damaged even though they are still holding pressure. The inside edge of the oring shreds against the inside of the hole as they get pushed down.

...could it be as simple as we are all using slightly out of spec orings, maybe due to availability problems?

I have ordered the minimum quantity ( 15 ) of this new size from the oring store - viton rubber 75. I will let you all know how it goes.

To make that clear:
The little auberin PID works like a charm. It is holding temp exactly on the value you choose. I just tried to optimise the heat up period. Bit 10 Minutes are fine anyway.
So I think for the price it is a very convenient tool and you can pull your shots any time you want. Also back to back.

Gravy - I had the same issue and posted the results of a brute force investigation where I tested different o-ring materials. The result was that all Viton o-rings of different hardnesses and profiles that I tried shredded. I had much more success with a buna one.

There are definitely 2 different sizes of o-rings for the piston vent on Caravels. The VAM1.1 version is smaller and Francesco does sell a kit of seals with the smaller o-ring. Here is a repost of my 4th of July red, white, blue and black picture and you can see that the hole in the rightmost piston is bigger than in the one next to it.

I've been using my Caravel a lot lately because my modern machine is down. The last couple of days, the lever action became stiff, especially when raising the lever, and feels like metal grinding on metal. For reference, my piston looks like the one on the far right of the photo above. I tried lubing the seals with some Dow 111, then pretty much every metal surface, but it didn't help. Any idea what the problem is?

AE wrote:To make that clear:
The little auberin PID works like a charm. It is holding temp exactly on the value you choose. I just tried to optimise the heat up period. Bit 10 Minutes are fine anyway.
So I think for the price it is a very convenient tool and you can pull your shots any time you want. Also back to back.

Ive been using the Caravel with the Auber PID a lot for a couple of weeks now, and I have to say I love it with the PID. It's not pretty with the temperature probe sticking in the boiler, and PID unit and power cords on the counter, but I can fill the boiler and it is at the perfect temperature in a few minutes without having to stand there waiting for the light to go out so I can pull the shot at just the right time.

Regarding the grinding noises, the most likely thing I can think of is that perhaps the lever handle ends aren't seated all the way in the oval holes of the piston hub.

Since you already took it apart to lube the seals, I assume you would have noticed if there were a piece of grit stuck in there or if the spring clip inside the piston came loose or broke.

Since I have 2 VAM 1.0 machines that are very similar, I decided to modify one of them with a holey piston from a Caravel. That piston happened to be for sale as a spare part on eBay. This project involves taking apart parts that were not meant to be taken apart, so, as they say, "don't try this at home".
I used a bearing puller but the puller is designed to push against the shaft that the bearing sits on. Instead it's pushing against a bolt that butts against the 2 lever arms. There are vise-grips holding these arms together. It's all quite dodgy:


I pried apart the newer piston assembly in a similar way, but ended up bending the hub and finishing the job with a hacksaw.
After pressing together the Frankenstein combination in a vise, this is the result:

UPDATE
The Caravel piston-with-hole did not quite work as well as I had hoped with the VAM boiler.
The piston would fill with water and if I lifted the lever too quickly, water would come out of the slots the lever goes into.
Lifting the lever slowly let the water drain down through that hole but this water is cooler than desired and who wants espresso made with water that's been inside the piston?
The problem is the 2 rows of holes in the VAM boiler, although I'm still not quite sure what path the water takes to fill the piston.
I thought of plugging up the top row of holes somehow but found that I could buy a boiler from a Caravel1.0 with the more modern single row of holes and the same mounting button on the back as the VAM boiler has.
Even that boiler is shaped a bit different; the lower corners are less rounded. I needed to file away some small tabs on the body of the machine to make it fit.
Now I've got that boiler installed and the water spilling problems are all solved.

I did it. I finaly got myself an Arrarex Caravel.

Apart from coming with a horrifyingly bad power cable that was essentialy live, neutral and ground all mashed together, along with an unsurpsingly melted power prong, the machine (after repairs) works almost perfectly. Some things left to do are reattach the plastic cover for the power switch, but it's not essential, as well as unstick the thermostat which seems to not do anything.



One thing that was missing was a tamper. After searching a few pages back, a user (I think it was AE) put me onto a fantastic idea, using a 43mm stainless sink plug that I found on Ebay.de for about 8 euros shipped.





The tolerances look great, and I think it's going to be dead simple to attach the handle. Here's a link to anyone who is looking for something convex to use on their standard baskets.

EDIT: Bonus pic of the old cable:


And another of what the cabling was like before. Yikes.