On Thu, 20 Mar 2025 at 22:25, Jim Pruitt WA7DUY via groups.io
<jpruitt67@...> wrote:
How do you clean the needles used to dispense solder paste? I thought I had it figured out as I got a 100ml luer lock syringe and ran 100ml of hot water through my #21 and #22 needles but the next time I try to use them I find them clogged and the last one I could not get it opened up again. I hope the needles are not 1 time use only.
Is there a way to actually clean those needles?
Soak in IPA, and run through with acupuncture needles. I use #26 and
#28 dispensing needles (on a dima dotmaster) and this gets them clean
when they inevitably clog. I also find that I have to warm the paste
and syringe assembly, a 55W headlamp bulb mounted near the home
position and run from a variable PSU does the job.
The acupuncture needles are available all over the place and aren't
expensive - (and far better than trying to poke stripped wire wrap
wire through a clogged needle)
(or Amazon, ebay etc.)
Some dispensing needles are 'lucky', some clog quickly. I think it's a
function of the transition of the needle tube projecting into the main
body - if there's a step the solder balls get hung up, squeeze the
flux out and start to create a pellet of solid solder under the
pressure. You can finesse this a bit if you need, the needles are just
crimped into the body, you can adjust the depth (with care).
I've also been trying one-piece dispensing nozzles with some success -
like these, but they're not 'better' enough to convince me yet, and
I'd have to modify the dotmaster to suit.
Steve
