What do you guys use to keep solder paste a little bit moist consistency? - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: September 10, 2014, 12:11:08 pm
content: I have one of those 2331-zx pens, but is a pain to get the liquid out of it. Do you guys use anything to give it a little more moisture?

author: rs20
author_rank: Super Contributor
timestamp: September 10, 2014, 12:31:08 pm
content: Your title is wrong; flux and paste are totally different things (paste has solder balls in it). 2331-ZX is a flux, not a paste.That aside,the datasheet for 2331-ZXsays "...the complex nature of the solvent system for the flux makes it imperative that Kester 4662 Thinner be used to replace evaporative losses." But obviously that's a bit over-the-top in your case. Is it one of those flux pens that release flux when you put a decent deal of pressure on the tip? If it's run out of flux, maybe it's best to just get a new one.

author: alank2
author_rank: Super Contributor
timestamp: September 10, 2014, 12:37:04 pm
content: Hi rs20, I get that they are different. My question is, when paste starts to dry out a bit and lose that moist shiny consistency, do you guys mix a little flux into it to bring it back? If so what do you use?

author: rs20
author_rank: Super Contributor
timestamp: September 10, 2014, 12:44:55 pm
content: Oh, sorry, I could never have figured that out from your original post. The flux in solder paste isn't just any old flux; I'd guess that it's specially designed not to attack the solder balls in the paste (and because the balls are so small, there's ahugesurface area of solder to be attacked there). If you just added any old aggressive flux into the mix, it'd probably react with the solder within days. I don't have experience with this though, so you should probably wait for other people more experienced than me.

author: Kjelt
author_rank: Super Contributor
timestamp: September 10, 2014, 01:12:03 pm
content: You have to find out which kind of flux is in the paste. If it is noclean flux then try to get a little bottle of it from the same brand, that is how I did it.Actually what you need is not extra flux but the solvent of the flux, that can be anything but you can try with a bit of IPA.What you can do to not spoil the entire batch is take out what you want to use and experiment with that amount, you can try any other brand noclean fluid flux or the IPA and see the results after one pcb reflow.It just takes a tiny bit (few drops) to make it nice again, however after a certain amount of time (few years) that won't help either and the original flux is perhaps too dried in to get good moist and you have to buy a new batch.

author: David Hess
author_rank: Super Contributor
timestamp: September 10, 2014, 04:30:18 pm
content: 2331-zx flux is one of those fancy organic water-soluble fluxes and the MSDS says it is mostly isopropyl alcohol so that is what I would use to thin it. For rosin fluxes I prefer a 50/50 mix of toluene and isopropyl alcohol.

author: alank2
author_rank: Super Contributor
timestamp: September 12, 2014, 01:44:17 am
content: Hi,I used a tiny amount of 100% IPA and it worked wonderfully. Stenciled very nice.Thanks,Alan