soldering problem

i ran into a little problem when i started soldering today. i can not seem to get that thin layer on the tip of my iron, it keeps rolling off. it worked yesterday for the first time, but not anymore. i wiped the tip real well with some wet cloth, doesn't seem to have any dirt or anything on it...what could be the problem...

ps. every time i touch the tip, it extracts some black liquid, and then it rolls up...maybe i should try different solder?

The black liquid I would guess is the rosin core of the solder.  It cleans the surface that you are soldering.  As long as it heats up whatever you are soldering thoroughly enough, I wouldn't worry about the tip of the soldering iron not being perfectly tinned. 

Steven Kephart

Adire Audio

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You could also try using a tip tinner like this Rat shack has some.

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I wouldn't worry about the tip of the soldering iron not being perfectly tinned.

that's the thing, it doesn't stay on the tip at all, it just rolls right off. (i start at low temp.)

and yeah, that tip tinner looks good. will see if they have it at home depot, perhaps? thank you for replies.

What are you trying to solder?  What you want to do is touch the soldering iron to the thing you want soldered and add a little solder to provide a good thermal coupling.  As soon as it gets hot enough, the solder will pull in, and you can add more solder until there is enough. 

Steven Kephart

Adire Audio

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Use thicker solder. I had the same problem when I solder boards on a PS2. Also, as suggested before, make sure that the surface taht your soldering heats up.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Sounds to me like the iron is not heating up to high enough temperature.  It's getting warm enough to extract the rosin but not hot enough to pull the solder.

The iron on the soldering gun builds up with oxidation and loses some electrical contact with the gun.   Loosen the holding nut, remove the iron and sand it to a copper color, then tighten it back into the gun.  You  should now get the proper electrical contact for full heat.

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What are you trying to solder?

radio harness (16awg)

thanks for all the tips.