I’ve got a Jun-Air as well. I picked mine up from a JA rebuild
technician who was cleaning out his closet, and I got a chance to
pick his brains during the chatting.
So, (A) it is incredibly important that you use the proper JA oil.
You can destroy the pump otherwise. You also need to install a
coalescing oil filter into the airline right after the tank, so that
all the output flows through it. ($50 or so via Grainger. If you
can’t find one, I can pull the part number off mine, but it’s hard
to get to immediately.) That strips the oil out of the compressed
air. (critical if you’re using a gravermach or similar.) It may
already have one. Check to see what’s on there though, as there are
non- coalescing water traps that look similar, and don’t grab the
oil, just the water. Gravermach’s will notice and care.
The pumps themselves are stunningly quiet. You’ll love it. It doesn’t
’need’ any special ventilation other than open airflow, but I keep a
pair of small muffin fans blowing on mine if I’m using it for a lot
of engraving. (Muffin fans=$10. New compressor if I cook this one?
$2000. Muffin fans it is…) Muffin fans are those little square fans
that one typically sees in the backs of computers. They’re not hard
to rig up, and they’re quiet.
I’ve never noticed mine emitting any fumes or grease. Mostly, it
just sits there and putters.