Most of the marine grade 2 part true epoxy products will have an adequate temperature rating. If you can find a decent boat yard they will have it on hand. Any mention of amine or mono-amine vapor during the cure process is the one you want. Things get hidden on labels.

Agree with Oldnuc, epoxy should do the trick and the right sort will also be able to deal w the temperature although I'm not sure about the effect of endless cycles of heating and cooling on the longevity of the bind but that is something time will tell...at first I'd call your LP dealer and discuss options....

Unfortunately I was not able to find epoxy in close range. The ones I found online do not offer online purchase. However, I found this option http://www.akfix.com/sayfalar.asp?Langu ... 60&b=detay

Do you think it will do the job or should I look for other alternatives?

Silicone does not bond well and will probably fail soon if not immediately as it is highly elastic.

If it was me, I would look for a replacement cap. Getting one fabricated may be expensive, but sometimes you can find a local hobbyist with a lathe that will do it for cheap. Craigslist, local clubs or a local college may be places to start looking.

Doing it yourself may not be as hard as you think. A rod of brass, wrench and this:
http://www.ebay.com/itm/1pcs-Metric-Rig ... 1687370133

Some YouTube videos will help fill you in on how to cut breads by hand, but some cutting oil and time it won't be too hard.

kahvedelisi wrote:Unfortunately I was not able to find epoxy in close range. The ones I found online do not offer online purchase. However, I found this option http://www.akfix.com/sayfalar.asp?Langu ... 60&b=detay

Do you think it will do the job or should I look for other alternatives?

You could replace it with a standard plastic cap, which is not nearly as likely to separate. Or, you could drill the wood and a bit of the plug to insert a set screw. I would be careful, though, to make sure it holds. I'm surprised, though, that you can't find epoxy on eBay.it and have it shipped to Turkey. But then I'm sure you are well aware of what's possible there.

Or this cap seems to have metal threads
http://www.shop.partsguru.com/LaPavoni- ... 012016.htm

Love this bit on the partsguru page you linked to

We do not recommend or sell lever operated home models with boiler that holds heated water. For classic espresso the water must be instantly heated, extraction pressure must be 9 Bars. The lever models do not provide any of the two.

A quick search brough me to www.polyestershoppen.nl which has 80 and 130'C proof epoxy and you can order online as far as I can see, just let me know if you need some help with the language.

Marcelnl wrote:Love this bit on the partsguru page you linked to

This "partsguru" also has a twenty minute video where he "debunks myths about Saeco pressurized portafilters."

The pressurized portafilters...they are all much better than the commercially used non-pressurized portafilters.

Apologies for going off-topic, but I got a kick out of that.

wkmok1 wrote:If you are unable to separate the 2 parts, do you think you can squirt super glue into the crack between them?

+1 for this option. I used to be prejudiced against Super Glue (no rational reason) but over the last 5 years or so have come to really appreciate its qualities for lots of different applications. So if the cap were mine, I would try to Super Glue it first. If that doesn't work, you can always try getting the pieces separated and epoxy them back together.