@mewertow As i didn't hear back from you on the best choice of Sn63Pb37 solder to use with the Voltera for applying paste to HASL boards, I bought some T4 from ChipQuik to try, as well as some standard paste in a 5cc tube which I haven't tried yet.
The T4 only came in a 10cc tube, so I had to transfer some of it to one of the 5cc ones I got from Voltera. Being new to this my technique was no doubt poor, and I probably got some air into it, because I found it just wanted to keep flowing even after I backed it off. In fact the T4 paste seems very runny, it doesn't want to stop flowing out of the nozzle, and leaves dribbles around the parking areas.
Anyway I tried using it to paste my boards, but without real success, and I ended up redoing them manually, using the cartridge from the Voltera! What appeared to happen was that instead of sticking to the pads, the paste was balling up around the tip of the nozzle, so most pads were left bare, with an occasional blob. To my eye the paste appeared to be curling around and creeping back up around the nozzle.
So I said to myself, this is obviously a symptom of the nozzle being too low. Or too high. Or the flow rate being too low. Or some combination of these and/or other factors.
Hence I thought it best to ask the clever people at Voltera for the benefit of their experience in such matters!