soldering help

Hi all, I have some trouble with soldering. First off, I want to state I am a total beginner at soldering - I started just 3 days ago. When I was soldering last night, the clear liquid that spreads from the solder (I believe it is called flux?...) went over a metal part of the pcb... So when I tried to solder again, the solder would not stay and solidify! Is it because of the excess flux because it itself has become a solid! How do I remove this ?

sorry for the repost in the general forum... I didn't find this one until after I had posted in the other

flux can be removed from pcb’s and parts by scrubbing with 99% isopropyl alcohol.

Rosin flux it is - its role is vital to get good metal-to-metal contact - it chemically reduces the oxide film on the surface of the metal and solder.

I think you need to apply the end of the solder between the iron and the board so it melts rapidly and then makes good thermal contact, thus melting the flux and then wetting the board (yes, solder is described as wetting a metal surface!).

Normally you would remove excess flux at the end of the soldering job using a suitable solvent and a brush, but it shouldn't aftect solderability during the process.

The two commonest soldering faults are using too cold an iron and not cleaning the tip and re-tinning it (add more solder) very regularly. Normally a small amount of fresh solder should be on the iron to improve thermal contact (and help speed up the process, allowing it happen before oxide can build up).

I'm sure there are some good videos on youtube that show how it should look.

A wire bristle brush (along with Isopropoalchol) is what we were taught to use at TAFE, flux is messy, but i find just your typical everyday washing up pad will remove the flux, dry it off and clean your soldering iron tip then re-apply heat to the solder joint.

Never use a wire brush on electronics.

what would you call it then, it looked like a paint brush but solid.... felt like some kind of metal brush tip, use a washing pad.

an old toothbrush works wonders.

have a look at this tutorial:

http://youtu.be/z7Tu8NXu5UA

advance to 22:15 for cleaning pcb's with isopropyl alcohol & coffee filters.

You can use a glass fibre brush if you don't want to use a wire brush. You can buy them in a sort of pen/lipstick form.

The standard cleaning brush usually goes by the term "acid brush", and is generally considered safe for electronics.

My personal preference is cotton swabs and alcohol, but I have used acid brushes and spray can flux remover before as well.

For small areas, try Q-tips with 99% isopropyl alcohol.

With scissors, cut the “acid brush” bristles to 1/4" long.

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