Incredible manufacturing skills. The machine will be fabulous.

Thank you barney! Looking forward to finishing.

Today's installment is the first foundry production part: the brew reservoir. I made the prototype entirely from discrete stainless parts, but the complex form means that it is much more efficient to make a casting.

The prototype reservoir from 2016.



After a lengthy exchange with the foundry: one bucket-o-castings! Slightly more costly than KFC.



The rectangular blocks on the face of the flange are casting "risers" that provide a reservoir of liquid metal that is drawn into the casting as it solidifies to prevent internal voids from forming.



The large void in the surface means that this one is likely a reject and will go back into the melting pot.

A few days later and the parts arrived at my shop. So easy!



As the foundry molds have to be made anyway, I thought I may as well add the detail of the threaded nub on the side of the reservoir. This is an easy place to unobtrusively attach a thermocouple - the data from which may or may not be useful. Time will tell.

Again, very, very good craftsmanship!

How is the pre-group reservoir constructed and how does the water flow through it!

Thanks Curtis!

To answer your question - the reservoir is formed when the fitting is welded to the outside of the boiler. The volume of the interior of the mitered tube (which is closed off at one end by the boiler wall and by the group itself at the other) is about the same as the piston displacement i.e. one shot. There is an inlet on the top of the fitting which is fed from the outlet of the horseshoe HX in the boiler. The outlet is through the wall of the group flange.

The reservoir (primarily the water inside) provides the thermal bridge between the boiler and the group with the thermal losses of the group to the atmosphere being made up by conduction from the reservoir water. And of course it also physically holds the boiler and the group on the frame.

LS,
I have been admiring this project from its start. Normally I am just leaching progress, but now I am starting to wonder if this project leads to inflation of existing Aurora B machines...
Great show!
Cheers, TY

Lol. Thx TY.

I think that there is already plenty of demand for Auroras - especially the single groups. Very hard to find!

bidoowee wrote:Lol. Thx TY.
I think that there is already plenty of demand for Auroras - especially the single groups. Very hard to find!

Dude, you're on a stairway to heaven...
In honour and admiration of your project, see below...hopefully giving you some positive vibes.
Cheers, TY

Hey nice machine!

Do you know what its origin is?
It looks from the case that it is from the US - is that possible?

Reworked electrics? New feet?

bidoowee wrote:Hey nice machine!
Do you know what its origin is?
It looks from the case that it is from the US - is that possible?

Unlikely, since I bought the machine (in bad shape) in Arnhem, The Netherlands.

Reworked electrics? New feet?

Yup, the whole shebang...I particulary like (and would also recommend) the auto-fill. Must be a piece of cake for you to do this mod. Happy to provide you with the details.
http://www.koffiepraat.nl/forum/viewtop ... &start=120

Cheers, TY

bidoowee wrote:Thanks Curtis!

To answer your question - the reservoir is formed when the fitting is welded to the outside of the boiler. The volume of the interior of the mitered tube (which is closed off at one end by the boiler wall and by the group itself at the other) is about the same as the piston displacement i.e. one shot. There is an inlet on the top of the fitting which is fed from the outlet of the horseshoe HX in the boiler. The outlet is through the wall of the group flange.

The reservoir (primarily the water inside) provides the thermal bridge between the boiler and the group with the thermal losses of the group to the atmosphere being made up by conduction from the reservoir water. And of course it also physically holds the boiler and the group on the frame.

Is the reservoir fed from the boiler water or via a heat exchanger? The fitting looks to be installed above what I would think would be the water level but I didn't see a place for a feed line fitting.