Modified/decorative La Pavoni boiler cap

Postby RayJohns on Sun Dec 30, 2012 4:32 pm

So while I was descaling my La Pavoni yesterday, I noticed that about half of the bottom lip of the boiler cap (which makes contact with the top of the boiler) fractured and fell off on the counter... hmm: the joys of 40 year old espresso machines :-)

To remedy this, I used the lathe to turn the rest of the lip off. I then shaped it with a carbide cutting bit and added a bit of a chamfer to help blend it. After that, used a file and some sand paper to smooth everything down a bit further. A little blue magic metal polish finished everything off.

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Here's the boiler cap after turning it down on the lathe and polishing it

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And here is the cap in use and on the La Pavoni

I don't think it turned out half bad. Exposing the brass and peeling away the lower edge of the cap not only added a nice decorative accent, but I think it also improved functionality and reduced the risk of further fracturing of the boiler cap material.

Ray
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Postby njtnjt on Sun Dec 30, 2012 5:44 pm

Looks great Ray. I think I would have had to just buy a new one...
Cheers!
-Nicholas

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Postby rpavlis on Mon Dec 31, 2012 10:56 am

La Pavoni went to trash all plastic caps in the late 1980s. The decent ones with a brass base are interchangeable with the plastic trash ones that came later. Turning it down like that makes it look a lot better than the original brass and plastic ones! You did a good job!

Anyone who has a brass base one that has the plastic top should not ever consider buying a new one if the plastic top break because it is fairly easy to replace it with hardwood.

I described how I made a brass base using an M32x2 die. I attached a piece of ebony to the brass as can be seen in the later part of the thread:

Making brass cap for la Pavoni Europiccola, etc.

Unfortunately it is a bit difficult to make brass caps like I did, there is a substantial learning curve! One can cut the threads either with a lathe or a proper die. As explained in the earlier post, I believe, I held the die in a lathe chuck instead of die stock because it is hard to align the die with the part otherwise.

At the rate La Pavoni is replacing parts with plastic they may soon be selling all plastic lever machines. A consequence of this is "New Old Stock" La Pavoni machines often sell for more than the new ones.
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Postby RayJohns on Mon Dec 31, 2012 1:13 pm

rpavlis wrote:Turning it down like that makes it look a lot better than the original brass and plastic ones! You did a good job!


Thanks! I'm pretty happy with how it turned out. Get it? "Turned" out :-)

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Postby zubinpatrick on Mon Dec 31, 2012 7:45 pm

FWIW when the sealing edge first fell apart I thought it was part the cap but it was actually a very hard old o-ring that was so compressed and hardened it appeared to be part of the cap. The Pav has a sealing o-ring that makes the final seal between cap and boiler
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Postby SAS on Mon Dec 31, 2012 8:42 pm

Very nice cap RayJohns.

Rpavlis made me a brass plug for my Europiccola and I added the wood. Thanks again Robert!
https://picasaweb.google.com/lh/photo/6D5ZTrFjcA_fIvl9kD8AEP3p715I4gsxwbVUvhYBMBk?feat=directlink

Also a redo of the Cremina cap after the bakelite one broke in half.
https://picasaweb.google.com/lh/photo/Mgd58leTZRxWA_HljHly2P3p715I4gsxwbVUvhYBMBk?feat=directlink

Cremina Steam knob.
https://picasaweb.google.com/lh/photo/qA2pwLKZokBRvToMTEfdTf3p715I4gsxwbVUvhYBMBk?feat=directlink

Sorry for the links, I was in a hurry and didn't want to fiddle with the size of the files and upload.
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Postby RayJohns on Mon Dec 31, 2012 10:29 pm

zubinpatrick wrote:FWIW when the sealing edge first fell apart I thought it was part the cap but it was actually a very hard old o-ring that was so compressed and hardened it appeared to be part of the cap. The Pav has a sealing o-ring that makes the final seal between cap and boiler


Yes, there is an O-ring involved.

On my cap, it was the lower edge of the top which cracked off. If you look at the photo above (or the zoomed shot below), you can see my O-ring just below the brass accent. It's been compressed down by the chamfer at the top of the boiler, which it threads down and compresses into.

Ray

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Postby DanoM on Thu Jun 06, 2013 7:33 pm

Yesterday I purchased a 1984 La Pavoni Professional that needs a little TLC. It's in working order, but needs all new seals, and DESCALE!!! Wow, the scale is finally starting to flake off the sides now after a few hours of a hot citric acid solution soak.

My cap, one of the metal+bakelite type, also started to crack and peel on the outside edge like yours. I was planning to repair it with krazy glue, sanding and polishing, but this solution looks pretty good too. I might just have to give it a try.

I was originally looking for a pic of the boiler cap to see if that hard thing was plastic or the o-ring. Thanks for adding that pic here, because my o-ring is every bit as hard as the bakelite! So that issue is solved, as is the issue with the cap edge peeling/cracking.

Now I just need to hope that the portafilter handle bolt will eventually come loose...

I'm hoping the pstat on this will be stable enough that I don't need to PID the unit, but if I do RayJohns' howto is really going to help.
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Postby rpavlis on Fri Jun 07, 2013 9:03 am

Unfortunately La Pavoni has used ordinary steel bolts on portafilters. The threads get wet during the espresso making process. Brass and steel are dissimilar metals, and this results in corrosion. It can be extremely difficult to remove the steel bolt from the portafilter after corrosion has occurred.

I would suggest applying penetrating oil to the threads and letting them sit a while. You might apply heat to the brass with a heat gun too.

Unfortunately it can become necessary to drill out the steel bolt. This is (very) difficult to do, it is best done with left handed drill bits. The hole must be drilled very carefully at the exact centre should this become necessary. If drilled carefully, you can use several every larger drill bits until almost all of the steel part is gone. Then you can take the correct size tap and use the appropriate tap to finish the job. This is painstaking labour!

One can buy brass or stainless threaded rod for replacement. However, the threaded rod pieces usually are one metre long--and thus a bit expensive. When I had this problem, I threaded a piece of brass bar stock using an appropriate die. You can usually buy short pieces of this stock very inexpensively. You can also saw the threaded part off brass or stainless bolts.

I described earlier in HB making new La Pavoni boiler caps from brass stock. It is much easier to start with a cap with brass threads like you have than to have to turn and then thread the brass part!

I would recommend using seasoned ebony if you need to replace handles. Although it is expensive, you only need small pieces. It is so hard that threads can be cut in it like metal, and if you have good ebony it does not have much tendency to crack. It has the further advantage of being very beautiful!
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