Can anyone tell me how to get a portafilter pressure gauge to seal well enough between the basket and group to keep it from spraying everywhere? Unfortunately with the machine I currently own, i dont have the luxury of a built-in gauge so I assembled one with a few fittings from the local hardware store and plenty of heavy duty Teflon tape. All the connections are leak-free but I can't get the portafilter locked in tight enough against the group gasket. Any clues?

normally you do not use the basket when testing with the portafilter mounted gauge

there are however some exception in which the portafilter will not work
example the older style rancilio portafilter that had a notch in the body

Thanks. Ill give that a try. I just don't understand why I don't get leaks with a back flush disk and do with the gauge apparatus.

coffeesnob1 wrote:Can anyone tell me how to get a portafilter pressure gauge to seal well enough between the basket and group to keep it from spraying everywhere?

coffeesnob1 wrote:I just don't understand why I don't get leaks with a back flush disk and do with the gauge apparatus.

If you have a basket in place, it's more likely the leak is between the portafilter rim and the underside of the basket rim, than between the top of the basket and the group gasket. During a normal (or blind) shot, the space inside the PF and outside the basket is at atmospheric pressure, so no seal is needed under the basket rim. You could twist some PTFE tape into a thin rope to seal under the basket rim (I once had to do this with one of those notched Silvia PFs), but as was noted, it's simpler to just take out the basket altogether.

I get it now. That totally makes sense. Thanks!