Why doesnt solder stick on metal? I thought it was supposed to stick on or at least rub off a little. Is there something I should do other than cleaning the contact points to make it solder on better or a type of solder? Thanks for the help.

 

There is always a very thin atomic level oxide coating on the metal. The purpose of the appropriate flux is to remove that oxide coating so the tin and lead mixture in the solder can get "happy" with the base metal.

If you are doing electronics work Kester 44 is a good all around not get you into any trouble solder. If you are doing body work, I used to use plumbers flux, or a flux I made by disolving zinc in muriatic acid.

Do not use plumbing flux or acid core solder on electronics. The flux will continue to be active and eat away the components and circuit board after the deed is done. Kester 44 is a mildly activated rosin core, there are other chemistries, but I don't think you will need them.

 

I've always used Alpha Metals solder - 60/40 rosin core. Clean it up with alcohol or a product called Flux-Off if your doing PCB work.

Remember, heat the 'work' first, then apply solder to the joint.

 

i have never used flux. like EE_Chris said....be sure to heat-up the metal with the tip of the soldering iron before introducing the solder into the mix>

 

hey bigmoose, so are you saying the Kester 44 is a type of solder? Where can I get my hands on some?

 

Yep. I buy all my solder and soldering needs from Wassco.

Go here for the page with Kester solder http://www.wassco.com/kesfluxcoran.html You may have to look at minimum order quantities. I usually need enough to now worry about it. Kester 44 is a good at home chemistry.

I also use the no clean 245 chemistry, but it does not flux as well. And stay away from the organic 331 chemistry. It fluxes well, but it MUST be cleaned.

BTW propanol (99% pure rubbing alcohol) will cut the rosin residue pretty well, but even though it is there you really only need to clean it for asthetic purposes.

Good luck. Any questions, just ask.

And about the heating tip above, I do not do it that way, but have a little different way that lets me meet space qualified quality. What I do is put the temperature controlled tip (700 C) on the work. Immediately place a little solder ON the iron tip where it touches the pad and wire. This helps the heat transfer to the joint, while limiting heating to other stuff and/or lifting the copper from the board. Let it heat one-one thousand two-one thousand, then flow in the solder to make a bright shinny joint with a nice fillet. Now remove the solder but keep the iron tip there one one-one thousand, two-one thousand, three-one thousand. Remove iron. Let cool with no movement till solid.

A little different, but works for me.

 

hey bigmoose, I will be using solder for mainly general uses such as wire connections, electrical boards, etc. So would you recommend the Kester 44 for my application? Lastly, would the Kester44 stick to metal or components better than regular solder from Radio Shack? Thanks for your advice.

 

The Kester 44 would be great for all the applications you described. It is what I have used for 27 years. It fluxes well, stores well, does not need cleaning. Its a good all around solder and flux chemistry for electronics and electrical work. When I looked Wassco had a sale on it too, at around 5 bucks a pound you can't beat that price. The other chemistries I mentioned I use for special situations only, that most likely you would not come across.

The trouble with the RatShack solder is you don't know what it is. Don't know the alloy, rosin activation, % flux, etc. If it works for you stick with it. It's just I can't use anything without traceable specs in my company. So I've never strayed from what certified and what we KNOW works. Definately not saying other manufacturers or chemistries will not work. EE CHris noted another brand/chemistry that works for him above. So to a degree, you are seeing our opinions based on our personal experience and our companies requirements.

If you are having trouble soldering components to a PCB check that the plating has not oxidized on the leads. Sometimes I have to use scotchbrite to clean them up a bit in the prototype lab. Even the Kester 44 won't work with lead oxidation. (Highly activated organics will, but you have to wash the board a lot after.) For production all the components are low shelf time and kept in hermetic or N2 to prevent oxidation. I also scotch brite any prototype PCB's before soldering if they have bare copper showing. I have a special board flux that I spray over the board before soldering, called SolderLac but its from Germany and you would have a devil of a time getting it..............

Hope this helps.

 

thanks bigmoose, you have been a great help!