What do you use to clean off excess flux from your projects?

[Paul Marossy]

er, i always thought flux was corrosive? at least mine turns my copper traces an icky, gooey, sticky green when left on for too long. i would definitely clean off excess, maybe not of solder or the board, or even wires, but definitely off copper pcb.

Are you using solder meant specifically for electronics, or just regular old solder like a plumber would use? Regular old solder will eat your PCBs...

[RedHouse]

We clean it off becuase rosin-flux is hydroscopic, it absorbs moisture out of the air and helps corrode your joints.

I use a toothbrush and Paint thinner, it comes off quick and then just a quick blow with an air can evaporates any excess rosin-flux

[vanessa]

There are times, and they are few that I have found that excess flux will cause a bridge between circuit points. This can cause a short in the circuit.

I have had this experience once, but no one seemed to believe me.  :?

It’s happened with Tonepad projects I’ve made do to the circuit layouts being so tight. I got in there with a brush and solvent and scrubbed some more and it worked. The one I made for a friend to this day is still running great. It had to be a short due to the flux, there was nothing else wrong with the circuit.

[aaronkessman]

was definitely high grade electronic solder.

[Paul Marossy]

was definitely high grade electronic solder.

Interesting. I have never heard of that happening with solder made specifically for electronics. Is it really humid where you live?

[moeburn]

Are you using solder meant specifically for electronics, or just regular old solder like a plumber would use? Regular old solder will eat your PCBs...

I'm using the cheapest plumbing solder I can find, and I still don't understand why I should clean this off.  I don't even know what I'm looking for on the board to be cleaning!  Could someone post a picture of a board that has flux that needs to be cleaned?

[Paul Marossy]

I'm using the cheapest plumbing solder I can find, and I still don't understand why I should clean this off. I don't even know what I'm looking for on the board to be cleaning! Could someone post a picture of a board that has flux that needs to be cleaned?

You're in for trouble! Read this article at GEO: http://www.geofex.com/Article_Folders/how_to_solder.htm

Flux is that clearish hard stuff around your solder joints that often appears after you solder something.

[aremesnik]

the plumbing solder joke was better then my jose cuervo joke

[Dai H.]

I use alcohol or naptha (zippo lighter fluid form). Sometimes it can take a lot of cleaning to get all the flux off (leaves white residue). I used some flux cleaner spray one time in an amp, and it left a big mess, melted a band off a resistor (guess it was some sort of solvent). That was a real pain to clean up.

[KORGULL]

There's also "no clean" solders. Kester makes some. Digi-Key sells it.
From Digi-Key cataolg:

"Nearly colorless translucent residues. Eliminates the need and expense of cleaning. Low smoke. Low odor.

[Fp-www.Tonepad.com]

That's what I got. A roll will last a LONG time.

Fp

[aaronkessman]

er, i'm talking about the flux you *add* not the flux that's in the core of the solder. I've never worried about that residue at all, as it's never built up enough.

[Paul Marossy]

There's also "no clean" solders. Kester makes some.

That's the stuff that I use.  

er, i'm talking about the flux you *add* not the flux that's in the core of the solder. I've never worried about that residue at all, as it's never built up enough.

Ah, I see. But why would you need to add more flux to rosin core solder?!  :?

[Mark Hammer]

The question was raised as o why clean off the flux.  Aesthetically, or electronically I have nothing against it.  For me, cleaning off the flux is a way of making the true nature of the traces and joints on the board clearly visible.  When something doesn't work right away, I'd like to know why, or at least be able to rule certain factors as irrelevant.  A flux-free board is simply a part of doing that.  Of course if the board is sparse, with huge spaces between pads, and I can visiually assure that there are no unintended solder bridges, then I am perfectly content to let the flux sit where it may.

[Fp-www.Tonepad.com]

The flux in the solder I use is absolutely clear, transparent. You can see thru it. In fact you can only see it when light hits it at an angle, so you can inspect the traces without removing it.

Fp

[sir_modulus]

I'm using standard kester solder...and my flux is somtimes brownish black, and sometimes clear...what's the deal?

Cheers,

Nish

[Paul Marossy]

I'm using standard kester solder...and my flux is somtimes brownish black, and sometimes clear...what's the deal?

Cheers,

Nish

I have wondered about that, too. I think it has to do with how long you apply the heat and how much solder you use. At least that is my theory.  

[D Wagner]

Ususally, I leave the flux on my boards without any problems.

But, I had been debugging a Pearl OC-07 octave clone for a few days, when I decided to remove the flux from the board.  I used a tooth brush and some acetone to do the job, then I rinsed it in hot water.  After it dried for a few hours, it fired right up!

Derek

[Paul Marossy]

Ususally, I leave the flux on my boards without any problems.

But, I had been debugging a Pearl OC-07 octave clone for a few days, when I decided to remove the flux from the board.  I used a tooth brush and some acetone to do the job, then I rinsed it in hot water.  After it dried for a few hours, it fired right up!

Derek

Weird when it does that, isn't it?  :?

[moeburn]

Ususally, I leave the flux on my boards without any problems.

But, I had been debugging a Pearl OC-07 octave clone for a few days, when I decided to remove the flux from the board.  I used a tooth brush and some acetone to do the job, then I rinsed it in hot water.  After it dried for a few hours, it fired right up!

Derek

Weird when it does that, isn't it?  :?

I don't think he meant it exploded...  :roll:

Although there was that one time where I tried making breakfast, and no matter what I made, it always caught on fire.  Even cereal.