soldering flux

RedlandMan

Active member
Joined
Mar 7, 2011
Messages
1,983
Reaction score
24
Location
Miami, Florida
Ive done a couple of cap kits and used a soldering paste that i used to use at work with a big soldering gun for thicker size wires. But dont like the color it leaves on solder and board. I thought on not using flux and just keeping the tip real clean but am afraid of solder not sticking. If i use the liquid flux will it look better in my solder joints?
 
Ive done a couple of cap kits and used a soldering paste that i used to use at work with a big soldering gun for thicker size wires. But dont like the color it leaves on solder and board. I thought on not using flux and just keeping the tip real clean but am afraid of solder not sticking. If i use the liquid flux will it look better in my solder joints?

Old boards - you'll need flux in one form or another.

Two options that I use...
1 -- use no-clean flux or solder with no-clean flux. The residue left behind is clear and far less.
2 -- use regular flux and clean it off when done. Alcohol works fine.

Ed
 
i use the .062 60/40 rosin core solder from radio shack. it's always worked well for me. i've never needed to use paste or anything. i just use desolder braid to take off the old shit.
 
i use the .062 60/40 rosin core solder from radio shack. it's always worked well for me. i've never needed to use paste or anything. i just use desolder braid to take off the old shit.

same here, and then use denatured alcohol to clean up any of the mess.
 
i use the .062 60/40 rosin core solder from radio shack. it's always worked well for me. i've never needed to use paste or anything. i just use desolder braid to take off the old shit.

Desoldering braid already has the flux (paste) within it to assist in pulling up the old solder - usually standard rosin. Makes life much easier but leaves behind quite abit of residue. Can leave it there... or, like many of us nitpickers, clean it up with alcohol.

062 is pretty thick stuff. I only use 062 for large items such as bridge rectifiers, large connectors, etc. For small stuff such as transistors, IC's, etc - I use .031. For real small stuff such as SMT - I use 0.015
 
Ive done a couple of cap kits and used a soldering paste that i used to use at work...

I hope you aren't a plumber by trade :D

There are a number of different types of flux out there, some cleaner than others, but most will do a decent job. Just make sure they are for electronics! Other kinds of soldering flux will have acids which will eventually destroy the board.

I now use some high quality re-balling flux paste that is an absolute miracle compared to some of the liquid stuff I have used in the past. It's clean and the solder flows like water with it, for some seriously nice end-results. A little of the high-test alcohol cleans it up like it wasn't even there.
 
no im not a plummer. I do transport refrigeration and alot of the newer stuff has microprocessors and control boards. The paste i used was for soldering in new switches and stuff like that.
 
i see alot of you use desoldering braid. I use it occationally but find it easier to use a desoldering iron
 
I hope you aren't a plumber by trade :D

There are a number of different types of flux out there, some cleaner than others, but most will do a decent job. Just make sure they are for electronics! Other kinds of soldering flux will have acids which will eventually destroy the board.

I now use some high quality re-balling flux paste that is an absolute miracle compared to some of the liquid stuff I have used in the past. It's clean and the solder flows like water with it, for some seriously nice end-results. A little of the high-test alcohol cleans it up like it wasn't even there.

Just to add a little more to this thread before it fades away.
This poster said there are many types of fluxes out there, which is true. But, in addition to his warning acid core fluxes (don't use!) -- we need to warn about certain types of electronics type fluxes as well.
For rework, don't use a "water-soluble" type flux. With water-clean flux, you absolutely MUST clean all the flux off! if you don't clean it, in a few months you will start to see the surrounding metals turn gray and pitted. This flux will continue to etch various metals over time. Kester 331 solder falls into this category -- I use this all the time for new boards that can be directly washed afterwards. for rework - I normally use Kester 245 solder... very clean and no cleaning required. I avoid AIM brand solder and flux - stinkiest stuff on this planet!
I've also found out...the hard way...that if you clip anything that was soldered with water-soluble flux (before it was washed) and don't clean the wire cutters - the edge of the wire cutter will disolve away.

Ed
 
I do SMT work for a living.

We use Amtech LF4300TF tacky flux for doing most work here. It cleans with water or alcohol, and even left in place, as it will polymerize on it's own and harden into a nonreactive substance. We use it for everything including BGA Placement. It has a short life (1 year refridgerated), and it's a little more expensive, but it's unbeatable for performance.

We also use Superior No.317 Alcohol-Based flux for fine-pitch work and BGA Reflow work. No clean, and it's about 85% volatile, so you're only left with a shellac-like film behind that is nonreactive as well.

After using this stuff, I won't mess with other brands/products. It costs more, but the nonreactivity of this stuff makes it worth the price.
 
When I worked in a PCB factory we used "no clean" flux-core 63/37 (63/37 being the eutectic mixture) solder for everything; specifically Alpha Metals [no clean] Cleanline SMT Core Plus in .015" and .025" diameter (we used the .015" for rework on surface mount components and the .025" for "through hole" soldering). We didn't generally clean the flux residue after soldering.

It was good stuff, and it is also what I use at home:

attachment.php
 

Attachments

  • alpha_smt_core_plus.jpg
    alpha_smt_core_plus.jpg
    52.9 KB · Views: 51
Back
Top Bottom