Europiccola dispersion screen split while replacing seals, need help

[garth breaks]

Folks,
My day couldn't have started off better - I received my new seals and was well into the replacement process (as outlined on Pavoni Express - http://www.pavoniexpress.com/sealrepl.html). When the time came to whack the piston a few times with a rubber mallet my machine wasn't really cooperating, but a few whacks later and I thought I was in the clear... Until I realized I had snapped the bottom of the dispersion screen out while the upper ring portion of it remains attached to the group. Photos are below.
This machine is from the early 60's, so I'm guessing the metal has somewhat (or completely) fused.
I need any and all suggestions for how I can go about removing the remainder of the dispersion screen despite the fact that there's essentially nothing to grab onto. Any thoughts (regardless of how far fetched) are greatly appreciated!

[Randy G.]

Folks,
My day couldn't have started off better - I received my new seals and was well into the replacement process (as outlined on Pavoni Express - http://www.pavoniexpress.com/sealrepl.html). When the time came to whack the piston a few times with a rubber mallet my machine wasn't really cooperating, but a few whacks later and I thought I was in the clear... Until I realized I had snapped the bottom of the dispersion screen out while the upper ring portion of it remains attached to the group. Photos are below.
This machine is from the early 60's, so I'm guessing the metal has somewhat (or completely) fused.
I need any and all suggestions for how I can go about removing the remainder of the dispersion screen despite the fact that there's essentially nothing to grab onto. Any thoughts (regardless of how far fetched) are greatly appreciated!

I hope I am wrong, but it appears that the screen is not the same design as the ones in the instructions. I am sure others can give you the correct info on that. I really hope I am mistaken- If I am right, you do not want to hear the answer.

IF the SHOWER screen you are holding is like the one in the instructions you link to (and it appears that is t is not), then if I were removing the remaining part would be to:

FIRST ATTEMPT: Get a tool to pry up the outer edge of the flange where it sits under the brewhead gasket enough to grab it with a pair of quality pliers.

SECOND ATTEMPT:
1) soak the area in a penetrant for a while
2) heat the brewhead evenly to about 200-250 degrees (heat lamp?).
3) apply something cold to the inside of the cylinder to cause it to shrink a bit (like a wet towel- BEWARE OF STEAM BURNS!).
4) remove the remaining part of the screen (ya, right).

THIRD ATTEMPT:
Grind off a hacksaw blade and use that to CAREFULLY saw through the outer area of the remaining part of the rim of the screen enough to get a srewdriver under it and peel it off.

[timo888]

SECOND ATTEMPT:
1) soak the area in a penetrant for a while

Nothing harsher than mineral oil--the kind that can be used as a laxative. You don't want coffee that tastes of WD40.

[happytamper]

Looks to me like you snapped a part of the sleeve that holds the dispersion screen in place.

An unlucky blow. However, I would try and reassemble the machine with the new gaskets and see if it works. Looking at your images i do not see any of the dispersion screen in the grouphead. Could you post a sideways view of the screen?

Maybe it would help to diagnose the problem.

[ideor]

hello garth,

the instructions you are working from apply to pavoni lever groups post-1974.

on pavoni europiccola and ambassador models made ca. 1960-74 the cylinder threads into the group body. the dispersion screen is machined into the bottom of the cylinder. on these units it is necessary to unthread the cylinder in order to withdraw the piston. the seat for the pf gasket has two pin holes spaced 180 deg. apart. these are used to unthread the cylinder. do not attempt to do this with a mallet and punch as this will only damage the holes. a tool must be made so that force can evenly be applied to both holes simultaneously. a good deal of torque will be necessary to break things loose. first remove the lever assembly. then remove the rubber base. this will expose the heating element and wiring. disconnect the wires to the heating element. now invert the machine and clamp the upper portion of the group body in a stout bench vise being careful to use cushioning material to protect the finish. it is necessary to pivot the base out of the way so the tool can be employed to unthread the cylinder. a band type automobile oil filter wrench can be used to unthread the heating element, being careful of the delicate terminals. with the heating element out the lockring which affixes the base the the boiler will be accessible. use a punch and mallet to loosen it. it is not necessary to remove the lock ring. just loosen it enough so that the base can be pivoted out of the way. when you get the cylinder out you will find there is a seal that goes between the cylinder and the group body.

the last two years or so before they went to the two-bolt flange group they made them with a snap on dispersion screen, ca. 1972-74. so your example must date from before that.

once you have the cylinder out you can better survey the damage. it may be possible to braze things back together and then re-machine. another possibility might be to machine in a groove to accept a later type dispersion screen. this route would offer easier servicing in the future.

hope this assists you a little. best wishes with the repair.

ideor

[bobcraige]

I think the repair might be best attempted by silver soldering (silver brazing) as opposed to brazing. Typically, brazing refers to using a brass filler rod on a non brass repair, but in this case you are attempting to join brass pieces which would then be of the same melting temperature as the fillet and would essentially be a welding process where in the base material melts and flows into the joint. Silver solder would melt at a lower temperature than the brass you are trying to repair and be a far more practical repair I believe. As I am far from an expert, I would seek a very expert welder to do this work as you will likely get only one chance. For a really good welder, this repair could be very simple and quick repair. For some better information regarding the various processes, take a look at this link:

http://en.wikipedia.org/wiki/Brazing

[Randy G.]

I think the repair might be best attempted by silver soldering (silver brazing) as opposed to brazing.

That is an excellent suggestion. The part that broke is not under that much stress and silver soldering would work just fine. A jeweler should be able to do it easily as they are accustomed to doing fine work on small pieces (the small, broken off piece). Even if the heat distorts the small piece a little it would not be noticeable and it would not affect performance of the machine.

[garth breaks]

Holy smokes, what great suggestions!
Thanks to everyone for posting their thoughts so far, I really appreciate it.
I'll be taking the base off this afternoon so I can get a better look at just what I'm dealing with, I'll upload photos shortly thereafter.
I really don't want to give up on this little baby, I've longed for a lever machine for too long to let this setback get the best of me...
Stay tuned and thanks again,
-GB.

[garth breaks]

UPDATE:
I'm heading out of town shortly, so it looks as though I won't be able to tackle this 'til mid-July.
I'll be sure to keep everyone posted when I do.
In the interim, I thought I'd repost an email that Dr. Pavoni sent my way, this is his second email to me and I've gotta say, he strikes me as a real top-notch fellow.

Brian, I'm sorry that you followed my instructions and broke your Group. This is the first time someone with your age machine & type of insert screen has contacted me involving a problem. That cylinder might have not been unscrewed for decades. From what I am told that repair is very difficult if not impossible to do. If that cylinder does unscrew from the Group, I think it will be very difficult procedure. You have to make up some kind of tool to do it. From your pictures I didn't see where the holes where located on the cylinder. I'm assuming you bought this second hand and didn't buy it for too much money. You didn't say if the machine works. Before you spend too much time and more money on this I would make sure that heating element is good. If the element is shot so is your machine. It's probably a screw on element which is not available anymore. The newer elements won't fit correctly and will leak. If you do attempt a repair please take some photo's. If the cylinder won't unscrew the other option is to replace the Group & piston seals and then slip the screen back into the groove and have the broken piece silver soldered back on. The only problem I see with that is keeping the Group cool enough so the new gaskets won't heat up and burn while the silver soldering is being done. What you went through is probably why you don't see many 60's & 70's machines in operation. This won't do you any good but I'll update the site on warning people to check and see what insert screen is in their machine. Let me know how you make out.

I like the soldering idea, but I'm also curious about the possibility of re-machining the cylinder to accept a more modern dispersion screen. Any thoughts on this are welcome.
(BTW - the heating element still works).
Thanks everyone,
-GB.

[AustinMike]

garth, can I ask where you found the replacement seals? I have this exact machine, right down to the European plug. Seeing your ordeal, replacing the seals makes me a bit nervous. Good luck with your repair.

[Spresso_Bean]

If I had to do this myself, I'd wrap the jaws of some pliers or an adjustable wrench (the type with teeth) with masking tape and grab onto the screen "basket" and try to wiggle it out. It's worked for me a few times, but that is just a suggestion in addition to the others up above.