I bought some Flux Soldering Paste

minkster · Post by **minkster** » Sat Apr 08, 2006 11:32 pm

A while ago, I bought some flux soldering paste and I thought it would be a "pasty texture" that you can apply onto wires. Unfortunately it doesn't seem to be that way. It is solid and I'm not quite sure how to use it ( I know this sounds pretty stupid ) Do I just dip my soldering iron in it to tin wires and stuff? I used to use lemon juice, but I want to try out flux. Sorry if it was a stupid question...I guess im a flux n00b

A.J. Franzman · Post by **A.J. Franzman** » Sat Apr 08, 2006 11:56 pm

What are you using for solder? Most of us use rosin flux core wire solder, which is hollow and has the flux built right in. Paste flux is usually used on copper water pipes, not electronics.

If you sometimes need extra flux for some reason, get a small bottle of liquid flux. It comes with a brush attached to the cap and you can just brush a little on whatever it is that needs the extra flux.

Stay away from the lemon juice - it is an acid and will eventually cause your circuits to fail by corrosion.

timmeh87 · Post by **timmeh87** » Sun Apr 09, 2006 12:10 am

liquid flux is also acid..

A.J. Franzman · Post by **A.J. Franzman** » Sun Apr 09, 2006 12:30 am

timmeh87 wrote:liquid flux is also acid..

You can buy acid and non-acid fluxes, just like you can buy solder that is rosin flux core or acid flux core. If you want your electronic projects to last, be careful if you shop in the plumbing section of the hardware store. They have a lot of acid flux products there.

The liquid flux bottle I have here (by GC Electronics) says right on the front of the label, "Non-corrosive flux for electronic and communication work".

The side panel (it's a square glass bottle) says, "This flux has pure rosin base and is completely non-corrosive and safe to use for all electronic applications."

Post by **Skyone** » Sun Apr 09, 2006 1:12 am

Eh, lemon juice is great.

If you are planning not to resolder anything, then it's ideal.

minkster · Post by **minkster** » Sun Apr 09, 2006 6:49 am

A.J. Franzman wrote:What are you using for solder? Most of us use rosin flux core wire solder, which is hollow and has the flux built right in. Paste flux is usually used on copper water pipes, not electronics.

If you sometimes need extra flux for some reason, get a small bottle of liquid flux. It comes with a brush attached to the cap and you can just brush a little on whatever it is that needs the extra flux.

Stay away from the lemon juice - it is an acid and will eventually cause your circuits to fail by corrosion.

My flux came with a brush, but its solid...so I'm kind of clueless how to use it. Maybe its the wrong kind of flux and isn't for electronics. I'll check what it says on the box later today.

Kurt_ · Post by **Kurt_** » Sun Apr 09, 2006 8:28 am

I believe I have some paste flux as well, although I use Liquid Flux. Both work equally well.

With paste flux (without a brush) I just dip my wires into it, and stick it on the *PLACE COMPONENT HERE* and solder normally. It works fine.

timmeh87 · Post by **timmeh87** » Sun Apr 09, 2006 12:24 pm

yeah. both our liquid and paste are acid and 'not for electronics'.

i like it more than the rosin that comes inside my solder because its much easier to clean off of the board, which i'd do anyways.

A.J. Franzman · Post by **A.J. Franzman** » Sun Apr 09, 2006 10:59 pm

Skyone wrote:Eh, lemon juice is great.

If you are planning not to resolder anything, then it's ideal.

Resoldering is not the issue, corrosion is. If you use a corrosive flux, you may be tossing that project in the garbage and having to re-make it from scratch in a few years' time. You can't resolder component leads that have dissolved...

How old is the oldest thing you've fluxed with lemon juice, and does it still work? How long do you want your electronic projects to last? If you don't care if they die unpredictably in about 0-10 years, then fine, keep using lemon juice. Personally, I like the fact that most of my 15-25 year old hobby electronic projects still work.

timmeh87 · Post by **timmeh87** » Sun Apr 09, 2006 11:16 pm

*shrug* i doubt lemon juice could entirely corrode a piece of wire.

i think we need mythbusters to try this.

A.J. Franzman · Post by **A.J. Franzman** » Sun Apr 09, 2006 11:52 pm

I suppose you've forgotten the "escape from a Mexican prison" segment? It used salsa instead of lemon juice (lemon juice is stronger) and managed to eat almost completely through a 1/2 inch steel bar overnight with the help of 12 volts DC.

psychotic_mechanic · Post by **psychotic_mechanic** » Mon Apr 10, 2006 12:12 am

A.J. Franzman wrote: most of my 15-25 year old hobby electronic projects still work.

Most of the members here aren't that old...

minkster · Post by **minkster** » Mon Apr 10, 2006 3:45 am

Eh, I think I will just stick with lemon juice if needed really badly. I just wont drench my projects in it thats all

G-force · Post by **G-force** » Mon Apr 10, 2006 1:46 pm

Crap. I ran out of rosin flux a while ago and ended up using some flux I found in my dads workbench. It says it has Zinc Chloride and Ammonium Chloride in it. Is that corrosive? (yes, my chemisty skills suck)
The name on the tin is "Oateys". It's a LOT eaiser to work with than rosin, this stuff just beads up (like water on a windshield) and evaporates and/or slides right off the board once you heat it up. Rosin just kinda melts into black crap. I'd like to keep using it if it's not acid based.
I used it to tin all the wires on my NESp, so theres nothing I can do about that now. I'll open it up in 6 months and see if anything corroded.

BTW, I have had rosin flux (from radio shack) start to corrode after only 6 months on my old N64p. I used a bit of an excessive amount, but it shouldn't be corroding at all.

vskid · Post by **vskid** » Mon Apr 10, 2006 2:07 pm

A.J. Franzman wrote:I suppose you've forgotten the "escape from a Mexican prison" segment? It used salsa instead of lemon juice (lemon juice is stronger) and managed to eat almost completely through a 1/2 inch steel bar overnight with the help of 12 volts DC.

Um, I think it was over the course of three months that it ate it away, and I thing it was mostly because of the electrolisic(however its spelled).