Water goes through the outer stainless steel coil, heated by the inner coiled element and encased in aluminum - I assume a solid cast aluminum block.

dalban wrote:EspressoForge / Andre, this thread is awesome! Thank you for your pioneering effort here, it's very inspiring.



Are you referring to the steam side? Or are you planning to rely entirely on a boiler, even for brewing? If you move to boiler, do you think you can get away with a single boiler, or will you go all the way to a dual set-up like Jorian did? How big a boiler would you need to make a single work (assuming you want both brew + milk)?

I'm pondering what it would take to embark on an adventure like this. Where are you (and other folks) sourcing groups from (LSM or Bosco)? Did you order your TB from Ascaso?

Thanks! Again, amazing work.

The brew side I'm pretty happy with. To be honest, I'm still not sure what direction I'll go. A boiler will add a lot of complexity and space, so I may still stick with the dual-TBs.

I ordered my group from a forum member, Terranova and most other parts from Ascaso and McMaster.

samuellaw178 wrote:Another question that crossed my mind the other day..does the aluminium block fare well in terms of corrosion? I imagine it's not in contact with water so might not be an issue?

That's supposedly the good thing about this TB as the diagram above shows, no water contact with aluminum.

EspressoForge wrote: That's supposedly the good thing about this TB as the diagram above shows, no water contact with aluminum.

I was actually wondering about the heat transfer/adapter block that is sandwiched between the metal frame and thermoblock. Not sure if galvanic corrosion would be an issue or if the relatively high moist environment would cause corrosion to aluminium in the long run (should be fine I guess).

Oh, well unless there's a leak, that also doesn't contact water at all on my design. A copper tube is fed directly into a brass fitting which adapts to the group. It's really just there for support and heat transfer. I am planning to trim it down and change it's design some as right now I feel it's just too large.

Makes sense. I was just being OCD after seeing corroded aluminium on some espresso machines (Gaggia, Peppina, microcimbali etc). They were in contact directly with water but not in your design.

I've been thinking about your complexity vs steam needs dilemma for a bit. Your approach with the thermoblock for the brew side results in an elegant and simple design. But, as you recognize, it becomes something of a compromise as soon as a steam requirement is added. While your personal steam needs are perhaps low, this cannot be said to be true for the "general case". If you want to complete the design for the general case, I don't see any way round the compromise of added complexity.

So what about using the steam-side thermoblock to fill and heat a steam reservoir - sort of like using a compressor to fill an air tank. If you bolted the block to the bottom of the reservoir, you could use it to heat the reservoir itself and fill it with steam. I haven't really thought through the whole design (it may well require a controlled fill-valve [though maybe there is another more clever solution]) but once the reservoir reaches >100C there should be no accumulation of condensate and it will be 100% full of saturated steam. Regulating the temp/pressure would allow you to control the 'wetness' of the steam. Just an idea...

bidoowee

I just read this entire thread... major props for conceptualizing and actually following through on this project! I love it. How is the thermoblock steam working out? If you were going to add a reservoir to the mix as bidoowee suggested, it would almost seem simpler to omit the thermoblock altogether and just have a boiler + heating element + pressure stat to keep the water at steam temp all the time. And this system would be completely independent of the PID + thermoblock for espresso. But if you do not use steam very often, then this is a non-issue for you altogether. I'm sure you could just use your BDB for steam as needed.

Reminds me of the Ascaso thermoblock.



http://www.ascaso.com/div-espresso-coff ... eam-3.html

KingSmono wrote:How is the thermoblock steam working out?

Not much progress, same as before. I'm planning a move, so the machine has been on a shelf for a while waiting till after the move.

KingSmono wrote:If you were going to add a reservoir to the mix as bidoowee suggested, it would almost seem simpler to omit the thermoblock altogether and just have a boiler + heating element + pressure stat to keep the water at steam temp all the time. And this system would be completely independent of the PID + thermoblock for espresso. But if you do not use steam very often, then this is a non-issue for you altogether. I'm sure you could just use your BDB for steam as needed.

Yeah this has been the major problem for me, just that I already have steam for the rare occasion on my BDB, and low amount of motivation since it looks to be a lot of work setting up a new boiler and ordering parts/fittings etc. It will materialize eventually for me, but right now since it is an Open Source idea I'm ready for someone else to innovate on the steam side who is a big milk buff.

redbone wrote:Reminds me of the Ascaso thermoblock.
http://www.ascaso.com/div-espresso-coff ... eam-3.html

I hope so! That's the thermoblock I'm using.

I just had a very simple idea. Maybe it is already discussed, can't see it but maybe it is already in here somewhere: if a boiler with pressure stat for steam is the better solution, then it would also be quite possible to have it on separate electric and water circuit, with it's own circuit breaker for the electrical, and a separate water feed pipe, or even a tank + small pump refill if that's more practical. Sounds like, for someone in the know, it would be possible to find an adequately sized boiler + pressure stat package.

I know for me that would be by far the best solution: I almost exclusively make cappuccinos or lattes when we have guests, but in those situations it would also be fantastic if I had a fast and powerful steamer. And in everyday use, I could save a lot of energy by only activating the espresso unit (thermoblock + group).