Solder paste syringe tips - Page 1
Forum section: electronics / beginners

author: jgalak
author_rank: Regular Contributor
timestamp: December 21, 2017, 08:39:51 pm
content: Ok, another dumb question:I got a syringe of solder paste that came with 3 removable tips, each tip with a tiny stainless tube (plus a "dummy" tip for plugging the syringe when not in use). I suspect I'll be using this syring way more than 3 times - my boards tend to be tiny.Is there a good way to clean the tip? It's currently full of solder paste. Can I push it out with a pin (if I can find one fine enough)? Water? Something else? Just buy more tips?

author: Teledog
author_rank: Regular Contributor
timestamp: December 21, 2017, 08:54:35 pm
content: If a pin/needle works, by all means use it..a bit of IPA also helps to clean it.Short lengths of stripped 30AWG wire-wrap wire work if it's not too clogged/dried up.Larger diameter (lower numeric gauge), and shorter needles also work better for squeezing out the paste.If it's a small project, I tend to just squirt out a small blob on a scrap surface, sans syringe tip altogether, and apply it to pads with a pin/short wire

author: nanofrog
author_rank: Super Contributor
timestamp: December 21, 2017, 09:27:41 pm
content: Quote from: Teledog on December 21, 2017, 08:54:35 pm+1Far more convenient this way, as there's no tip to clean. FWIW, I've found even a toothpick will work for application.If you're working with a larger project, the plastic cone shaped needles don't require as much pressure on the plunger to apply the paste. Next step would be get paste in a jar and apply with a stencil and use a reflow oven.

author: jgalak
author_rank: Regular Contributor
timestamp: December 21, 2017, 11:43:00 pm
content: I was using a stencil. Probably didn't need the spring tip. Oh well.

author: Ian.M
author_rank: Super Contributor
timestamp: December 22, 2017, 12:10:44 am
content: First check your paste's flux is fully soluble in IPA. Then store the tips in a small tightly sealed glass jar with a few mm of IPA in the bottom. In a solvent saturated atmosphere, the paste in the tip cant dry out. Blot off as much IPA as possible before use and discard the old paste in the tip.

author: nanofrog
author_rank: Super Contributor
timestamp: December 22, 2017, 12:22:44 am
content: Quote from: jgalak on December 21, 2017, 11:43:00 pmNope.Oh, and stencils are easier to clean IME.

author: jgalak
author_rank: Regular Contributor
timestamp: December 22, 2017, 12:59:23 am
content: IPA? I'm assuming you don't mean the beer?

author: nanofrog
author_rank: Super Contributor
timestamp: December 22, 2017, 02:18:59 am
content: Quote from: jgalak on December 22, 2017, 12:59:23 amIPA = Isopropyl AlcoholYou could also useKlean Strip Denatured Alcohol(non-green variant). As it's just ethylene and methylene, it won't leave a residue once it's all evaporated (unless there's still flux residue remaining).SDSfor it (formulation is on pg. 3). Cheaper than 99.5%+ IPA ($15.98/gal).

author: jmelson
author_rank: Super Contributor
timestamp: December 22, 2017, 03:04:26 am
content: Quote from: jgalak on December 21, 2017, 11:43:00 pmOh, definitely SKIP the syringe when using the stencil. You can mix the paste better from a jar. Otherwise, the solder separates from the flux, and becomes troublesome. I just dip out a glob of the paste onto the stencil, and then (against recommendations) put the rest back when done.Jon