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

?

Hello Steve.

I do not see any acupuncture needles available from Amazon on this side of the pond.? The other site also in the UK that you linked seems to require being a licensed acupuncturist in order to buy the needles.? I do like the idea though.? Now to find a USA supplier.

Thank you.

Jim Pruitt

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

?

?

?

?

?

?

Hello Steve.

I do not see any acupuncture needles available from Amazon on this side of the pond.? The other site also in the UK that you linked seems to require being a licensed acupuncturist in order to buy the needles.? I do like the idea though.? Now to find a USA supplier.

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of
Steve Wiseman via groups.io
Sent: Friday, 21 March 2025 4:59 pm
To: [email protected]
Subject: Re: [homebrewpcbs] cleaning paste needles

Ah, they're sold as 'printer cleaning needles' on Amazon uk, in handy kits of
different sizes.

(I have also bought a bunch of 3d printer nozzles, including the jewel tipped and
0.1mm versions, to see if they'll dispense solder paste, but they're still on the
'to do' pile. )

Steve