Robert (mostly) or anybody...

Robert has mentioned frequently in posts about the standard mild steel stud that joins the composition portafilter handle with the brass portafilter and the reactivity that causes corrosion. Robert has suggested that at the least, we should consider wrapping the steel stud with teflon plumber's tape, which is easy enough, and I have done it.

I wonder if it is even better still to use common anti-seize compound? The one I have around most often us the commonly available Permatex branded stuff with aluminum, copper and graphite in a very fine paste with some petro based grease. Robert, or other chemist types, are the materials in this compound a threat to increase reactivity between mild steel and brass? This stuff is very effective in stopping Fe-on-Fe reactivity, but I don't know how it might work in an Fe-brass interface, and worry that it might actually make things worse.

-Peter

I would throw the steel stud away and replace it with at least stainless.
http://www.ebay.com/itm/Hex-Head-Cap-Sc ... 4d103f6076, cut to length.

The nasty problems that have occurred with steel threaded rods in brass portafilters stem from the steel corroding from contact with a dissimilar metal in the wet environment. If such threaded rods are left in place for long periods of time, they will corrode more and more, and eventually they will break off and it becomes seriously difficult to remove them. If one take apart such threaded rod parts frequently they will not seize, but will be seen to be slowly disintegrating! Teflon tape at least partly insulates the parts electrically, and also is ultra slippery, making it easier to remove even should corrosion occur. I suspect anti seize materials might help remove disintegrated threaded rods. Anti seize materials are good also for identical metals that can seize from having protective oxide coatings removed with a "cold weld" forming. Stainless steel against stainless can do this, especially in situations where bolts are tightened strongly. Titanium and aluminium are also infamous for this. This problem becomes greater at high temperature. Usually threaded rod is sold in metre lengths, but one can, as suggested in the previous post get a bolt with the same thread diameter and pitch and saw it off. (You need a sharp saw to cut stainless, and you need to have the blade constantly cutting or it will work harden.)

M12 X1.75 mm threaded brass rod and antiseize will solve the problem. The trick is getting the firmly stuck steel stud out of the brass filter holder body without rendering the filter holder junk.