thread locker / sealant for espresso machine maintenance I have started disassembling my Nuova Simonelli Oscar, for descaling and fixing purposes, I have checked all the electrical section and I am about to start with the hydraulics.

I have seen that all threads are fully locked and sealed with some hard material, I assume I will have to place it back reassembling it. What kind of thread locker / thread sealer / gasket sealer / gasket replacement is that? can I use any that will sustain high temps or it has to be food safe?
You can use pretty much every kind of drinking water sealant that you would use in home installations. You DIY–/ Homework–market (I do not know the English word), normally has such stuff. Just make sure it meets three requirements:


For drinking water
Can be used with boiling, hot water
Does not harden over time


There is no number one choice. I personally used plastic–fermit (which is used for home hat water drainages) with success. I do not even need tools to lock down threads, all are just tightened by hand and it opens easily again.

Usually the manufacturers use something that I would recommend to avoid like the devil the water: PTFE/ Teflon. This locks things down forever. One winding too much and you will break your thread when trying to open it.



Edit: As grease, I can recommend to use silicone. The thing I used on my current machine is by fermit again. If it does not get in contact with water, I would recommend using copper paste (for e.g. by Liqui Moly), which can be used up to 1.4k°C. You will need the grease only for the steam wand and hot water outlet. If you are unsure what to buy, search for (German/ DE) Amaturenfett or Hahnfett, which is safe for hot potable water and is used for bathroom fittings and similar.