Do you have brick jointer or
similar?

Aye - but it'd not be my tool of choice for pushing muck as it's
rounded. In any event, my learning difficulty is with making the muck
stand proud of the joint without getting muck all over the face of the
brick. So I usually end up with a brushed "flush" finish which looks
pretty poor on old bricks with meandering and chipped edges.

That's the thought that went through my mind when I saw the tool. The
mix would have to be really soft to squidge through the nozzle
without having to apply loads of effort to the plunger. So soft that
it would probably slump out of the joint. Off a trowel with jointer
you can use a nice stiff mix that stays where you put it...

I've not had that problem. Bear in mind this tool has a large nozzle -
much larger than others I have seen - so "light and fluffy" does not
mean "runny as **** water". I've not tried to measure the hardness of
the result but it resists my thumbnail so I reckon it'll see me out

--
Robin
PM may be sent to rbw0{at}hotmail{dot}com