Real brass or fake brass re: used La Pavoni Europiccola - Page 2

A haven dedicated to manual espresso machine aficionados.
User avatar
rpavlis
Posts: 1799
Joined: 12 years ago

#11: Post by rpavlis »

An easy way to replace the steam tip is to find an M6x1.0 brass "acorn" nut and carefully drill with a 1.4mm bit at the very centre. If one want to make cappuccinos one needs "hard" foam, and the high speed single hole tip works best for this, in my opinion. The 1.4mm is the result obtained by an engineering formula, and when made that way they are indeed optimised. It is very easy to make such a tip with a small lathe too.

The IR thermometers are terrible on chrome surfaces, one needs to put an emissive tape over them, but the polymer used to protect brass is highly emissive, so the temperature can be read very very accurately on the normal coated brass groups. The correction for less than 100% emissivity seems very very slight.

The use of ramekins, as I mentioned above, is really helpful for temperature control and for cleaning the base of the group after each shot. It cleans, and as it heat up one can monitor the temperature and pull the shot when the correct temperature is reached, which will be less than half a minute after the ramekin treatment.

Each shot needs to be the same "length", which means you need to reduce sponginess to a bare minimum. Unless the shots have the same length they will vary dramatically, because the compounds in the espresso elute at different rates. (Bitter components come out last, acidic ones early.) With a 14 gram load of coffee, the bottom of the group between 88 and 90 at the start of the pull, and zero sponginess I find it most ideal to my taste. Late lock in can get rid of almost all the air trapped below the piston. Also too fine a grind retards the ability of the incoming steam and hot water to drive out the air. It also makes espresso with little crema. You do not want "gorilla pulls".

User avatar
redbone (original poster)
Posts: 3564
Joined: 12 years ago

#12: Post by redbone (original poster) »

In the process of taking the piston off for inspection and cleaning.
Concerned about inside of P.F. and considering getting it chopped. Had similar issue with brassing on my Zacconi which imparted a negative brass taste in the cup. Also hated cutting it but it made a hugh difference in the cup.
Between order and chaos there is espresso.
Semper discens.


Rob
LMWDP #549

User avatar
rpavlis
Posts: 1799
Joined: 12 years ago

#13: Post by rpavlis »

I would get one of the available bottomless portafilters rather than chop with the brass-copper model. This is because any spray that gets onto the copper boiler looks ugly. I also have a sheet of heat resistant plastic I use to protect it when I use the bottomless one.

I tend to use the naked one the most, but not always. I never use anything but stock when I take the machine to other places. I have one of each of the two available, the Cafelat one and the Naked one from Hungary. I did not realise that the Hungarian one worked on La Pavoni when I got it, because I got it for a Micro Casa a Leva. It has a peculiar ambidextrous lug set that lets it fit the left handed La Pavonis and the right handed Olympia and MCAL.

You need a slightly higher temperature at the group base with the stock brass one. I never considered chopping it because that is an irreversible thing to do. A great advantage to the Cafelat one is that you can get a base to fit on it so you can have both ways. Because stainless is a terrible heat conductor it seems not to make much difference whether you have the bottom in place or not.

User avatar
redbone (original poster)
Posts: 3564
Joined: 12 years ago

#14: Post by redbone (original poster) »

I do hate to do something irreversible on the same token it's all about what's in the cup. Looks like I'll be hunting for a bottomless P.F.. I found similar spraying issues with the bottomless Caravel P.F.. Wonder if the spraying would be minimized with longer wall on the bottom of a naked \ bottomless P.F. ?
Between order and chaos there is espresso.
Semper discens.


Rob
LMWDP #549

User avatar
grog
Posts: 1807
Joined: 12 years ago

#15: Post by grog »

I've found that spraying on shots is indicative of one of two things (and sometimes both): beans that are getting stale, or sub-par basket prep. It has taken me much longer than I would like to admit to finally get my basket prep down, and bottomless PFs have been a great learning tool along the way. I was a late adopter of WDT but it makes a huge difference - and only adds a couple of extra seconds to your basket prep routine.

I agree with Robert on getting a bottomless rather than chopping your stock one.
LMWDP #514

User avatar
drgary
Team HB
Posts: 14345
Joined: 14 years ago

#16: Post by drgary »

Spraying from a bottomless portafilter can also happen when there is too much coffee in the basket. I would think a good cleaning would be in order, then maybe a thin coating of DOW 111 on the inside of the portafilter to put something neutral between the brass and the coffee if you detect something odd with the taste. Keeping in mind that the inside of the boiler is probably copper or brass, if that doesn't impart taste maybe it's a matter of keeping it clean? (Just asking. What do others think?)
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

User avatar
rpavlis
Posts: 1799
Joined: 12 years ago

#17: Post by rpavlis »

There is also a tendency for tiny droplets to form when the very first espresso exits, because there is nothing under it, and it is moving at a substantial velocity as it exits. After a flow is established there is liquid under the tiny droplets as they emerge. The trouble is here is that the slightest droplets result in an ugly copper boiler because there are things in the coffee that react with the surface. The optional Cafelat bottom is well designed, and the whole thing is stainless, so it takes away less heat than a brass portafilter because of lower conductivity. (The heat capacities of all metals are essentially the same, about 3R per mole. However, molar volume varies a bit. Still for this issue heat loss variations are mostly from thermal conductivity.)

Actually there is some advantage to a heavy stock portafilter, because there is more metal in it, and it keeps extracting heat from the bottom of the group when the shot is being pulled, and the fairly high heat condutivity of brass makes this more the case.

Espresso is weakly acid, so there could be some tendency to extract Cu and Zn. That is why we need to clean espresso equipment after use. Sometimes nasty oils and the like get trapped in the spouts. One should really wipe out a portafilter after each session and be sure that it is clean.

Sometimes bad flavours develop also from failure to service groups frequently enough. This is a universal problem, not just La Pavoni!

The ground coffee needs to be stirred, and it needs to be even on the filter basket before tamping. Uneven distribution of fines creates a tendency to spurt with bottomless, because the espresso moves more slowly where there are more fines, so it rushes through other points.

User avatar
redbone (original poster)
Posts: 3564
Joined: 12 years ago

#18: Post by redbone (original poster) »

Decided to pull a shot on the new to me LPE Brass. Somewhat of a dissaster as I noticed a air/steam leak between the boiler and the group. I removed the group from the boiler, cleaned up inside and replaced the seal. Reattached but only tested sans coffee in basket, no apparent leak.
Further issue was placing the second P.F. on the group. I was not able to tighten the P.F. with a basket in it. Felt like the seal was sitting to low although I pushed it up as far as I could. Tried cleaning with brush as it seemed some grounds got in the way but no luck. Newbie testing with the LPE Brass continues.
I did used the P.F. from my 73 LPE since it was in better inside shape than the brass one. It did not seem any tighter a fit when dry fitting vs the stock P.F..
Wish the steam wand was longer and further away from the boiler. It seems to be to tight near both the boiler and over pressure release tube.

Robert the acorn nut idea seems great. How does one drill an exact 1.4mm hole ? I'd like to send you a few with return postage. :wink:
Between order and chaos there is espresso.
Semper discens.


Rob
LMWDP #549

User avatar
rpavlis
Posts: 1799
Joined: 12 years ago

#19: Post by rpavlis »

I suggest you measure the bolts that hold the group to the boiler. Their specifications call for 14mm long ones, but many are only 12, and with a little lead in for the tapped hole in the boiler there was not enough turns to hold it adequately. I mentioned that I replaced the M6 bolts that were only 12mm long with brass ones that were 17mm. (I cut 20mm ones so that they run clear to the bottom of the bore.) I noticed that mine would leak steam when I pulled down on the handle, even fairly lightly. After I put longer bolts in there were never any problems with this.

I fnd that there seem to be at least two diameters of the O ring that seal to the portafilter. Some 2nd generation groups seem to require thinner O rings than others.



I have posted similar images to the one above, but it shows the current state of my 1998 machine. Note the bullet shaped steam tip, the spike nuts, and the brass handle. The steam control knob is brass and ebony, and the cap also is. The spike nuts are weird, I got them from a motorcycle place, they have M6 threads, but the head requires Whitworth tools!

User avatar
redbone (original poster)
Posts: 3564
Joined: 12 years ago

#20: Post by redbone (original poster) »

The bolts that hold the group to the boiler were indeed only 12 mm. I've ordered ready sized 16mm and some brass acorn nuts to make a single hole tip. (Always keep the original parts that came with a machine.)
Both the tip and the tube have a clear coating that has flaked on the end. I think un-coated would have been better in this case. I have to figure why the P.F. is overly tight and hard to connect to group. Current seal is round I don't know if that's OEM as flat would appear to offer a better fitting.
The one great point of the machine is that it heats up really quick when both switches are on.
Outside minor quibbles the machine is in good condition. The rest will depend on my technique which is yet to be established as it seems to differ with every machine I find.
Between order and chaos there is espresso.
Semper discens.


Rob
LMWDP #549