Which no-clean flux would be best for general purpose modding tasks, drivers, mcpcbs, springs etc.?
Here’s the ones I’m looking at, I’m thinking the 959T, but wanted to see what others think and are using.
RMA (Rosin Mildly Activated)
RA (Rosin Activated)
Conductive Residue
Pick either the 959T or the 186.
Don’t even touch the 951. It is not meant for electronics. Correct me if I’m wrong, but it has an acid core, meaning it will damage electronic components over time.
I use this for reflowing. https://www.digikey.com/product-detail/en/chip-quik-inc/SMD291AX50T3/SMD291AX50T3-ND/5130159
This for flux. https://www.ebay.com/itm/1-4oz-KESTER-186-NO-CLEAN-FLUX-FOR-PS3-YLOD-FIX/130565848998?epid=1931630843&hash=item1e6654bfa6:g:f~8AAMXQ-BZQ~Sbq
And this solder. http://slotblog.net/topic/82041-wanted-radio-shack-silver-bearing-solder-62362/
Radio shack is almost gone and my solder was almost gone until I found another roll in a small town at one of the very few shacks that’s still open. I have tried 2 different brands of 62/36/2 solder and none are as good as the 64-013. This is the best solder I have ever used and makes a good shinny connection. You can google search it and see just how many people liked this solder. I just wish I knew who they sourced the solder from. I get a anxiety attach ever time I start to think I might be running out. :confounded:
I believe the 951 is for electronics but I’m not entirely sure, but yes I will scratch that one off my list anyhow.
According to Kester’s description (951): “suitable for automotive, computer, telecommunications”
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There seems to be quite a difference between 186 and 959T because of the rosin content, what I’m beginning to understand is that it’s the rosin that needs cleaning, the 186 has more rosin because it’s for uses where better fluxing is critical, but still needs the classification of RMA, so I think it has the most rosin possible and still remain under that classification.
The 959T has less rosin and is said to result in the most “shiniest solder joints”
So now I’m thinking the 959T would be ideal for drivers and mcpcbs and the 186 better for tasks that may require better fluxing, such as soldering large brass/copper parts, pills, torch soldering etc.
Thinking more about my above post on the rosin, the solder I’m using has rosin core and I’d actually be mixing the fluxes, so maybe the 959T would be best since I already will be adding some rosin from the solder itself:
I have a 21ft. tube of this Ersin Multicore
And a 1 lb. Spool of Kester 44 Rosin Core (will probably last a lifetime)
Hell if I know what mine is, but I was gifted about 1pt from a gallon jug of “organic flux”, blue stuff that looks like washer-fluid, but works like you wouldn’t believe. Spotless solder joints, fizzes away to nothing when you heat it, nothing to clean up.
Ahh, then you have the Organic Blue “mystery juice”. 
I did read that rosin is made from tree sap.
For anyone else that comes across this older thread during a search, I would just like to note that Kester 951 is an excellent “no-clean” flux for electronic work. I think BlueSwordM was thinking of conventional acid core solder used, e.g., for bonding steel. 951 is Matt’s (V. of B.) first choice:
IIRC, I think the reason I use the 951 is because PilotPTK did. It was either him or RMM, but probly Pilot. Been using it for a bunch of years now. Its excellent for everything accept reflowing. Been through about 8-10 of the 2oz bottles.
I have 959T as a liquid flux, but I hate liquid flux. I have MG Chemicals 8341 as “tacky flux”, and while it is advertised as no clean, it is anything but in practice. So I keep something that resembles a toothbrush and some isopropyl.
If anyone has recommendations on a better tacky flux, I’m all ears.
This is the best flux I have ever used for flashlight and electronic use.
Its amazing flux, so much easier than anything I have used from kester. The best part to me about this flux is it doesn’t evaporate away quickly, it stays in a liquid state a lot longer than regular flux which gives you more time to make the solder joint.
What got me turned on to this was watching youtube videos of louis using this stuff in repairing Macbooks that apple said was unrepairable.
Since then I have seen several different electronic repair youtubers use this same flux. Just a few weeks ago my galaxy s6 crapped out and woudn’t turn on.
I was hoping to repair it, searching youtube for some guidence. Sure enough they were using the same Amtech 559 to repair iphones and android phones.
If the professionals are using this flux on a daily basis then it has to be top notch. They do this for a living where having good tools for the job is a must for them no matter the cost. I feel like if they were somethng better they would be using it.
You can fastforward to about the 1:45 minute mark. It cleans up very easliy with alcohol.
Also be aware that they are fakes coming out of china, I have heard some say it works as good but I have also heard that it doesn’t.
I’m in no way affilated with Amtech or any of the youtubers, I just like the way this flux works and hopefully help someone else that might be having issues with what they are using.
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This 30cc tube should last you years. I have used about 5cc in one year. I dispense it into a (tractor supply) 5cc syringe with a heavy guage needle with the tip filed blunt. Allows for very precise displacement.
I got a bottle of Kester 951 last year and couldn’t really find a good use for it. It’s so volatile I have to keep the bottle in multiple bags so it doesn’t stink up my work area, and it’s incredibly thin and practically evaporates if you breathe on it. I prefer a regular no-clean flux that’s thicker and doesn’t evaporate so quickly even though I always clean it up anyway.
Cool - I had a coworker a few years back that showed me Louis Rossmann. Pretty entertaining and informative at once. As for the flux, sounds like it might be what I’m looking for:
I dont think you’ll have much need for anything else once you try it, unless something better comes out. 
I forgot to mention. When I was doing microsoldering professionally, we didn’t use a no-clean flux because it was manufacturing, so everything went through a boiling organic solvent bath anyway…
I’m pretty sure the “no clean” just means that no chemicals are left behind that will deteriorate the joint over time. The 951 is the closest I’ve found to a no residue (it still leaves some) which works okay for production stuff because I have control of when and how the joints are made. Wires are soldered on to mcpcbs first and then put on heat sinks VS modding where you may be forced to make joints in a difficult area with parts already on a sink etc.
Yeah - it’s always fun when you’re keeping your leads short and then you have to solder to the MCPCB at the bottom of the reflector hole and then clean the flux after so you don’t smoke it up. I really try to solder to the MCPCB first but sometimes it just doesn’t work out - and sometimes I could have, but didn’t plan ahead well enough