cored solder vs coreless solder

When using an external liquid flux source for hand soldering - is it advisable to still use a flux cored wire ? Or would it be better to use a pure coreless wire ?

My friend flux is ok to use always. In lots soldering material already there is small amount of flux. For some situations flux must be used. Better soldering is with flux. You should try to use it and soon will see difference, and rest will come with expirience.

Hello Shaiko,

It depends on the type of liquid flux. I use CW8300 water soluble flux, together with my cored solder frequently. This goes very well.

However when I use Zinc Chloride containing flux with cored solder, I get black thick residu on many surfaces that hinders wetting of the metal surface. When using non-cored solder with Zinc Chloride flux alone , it goes well without the black sticky residu.

After removing the Zinc Chloride residues (with water and soap as it is corrosive), you can do further soldering with cored solder.

So best is to do some experiments on the materials that you have to solder.

I generally dab a bit of flux on the work before heating it. I believe this keeps it from getting tarnished/oxidized, prior to the solder reaching it.

Often I tin each surface before the final join, because I want to watch it 'take' the molten solder. Especially at times when the job needs to be finished quickly so as to keep the heat confined, as when I'm soldering a substantial piece of metal, or soldering wires to the end of a rechargeable cell. Don't want to make the cell explode.

BradtheRad,

I'm trying to find reason in using cored solder wire when flux is already applied externally...?

You can search youtube videos for examples of flux soldering, can be very usefull.

Today you can use flux in pen, this is precize and flux is just on pins place.

Tpetar,

I know all the important facts about flux.
What I'm asking about is the use of cored solder together with liquid flux - does it make any sence ?

Solder wire is commonly used for manual soldering work and it’s a metal alloy that has two or more metals which are combined to produce a single metal. It is very well known for its benefits of combining together other types of metal by heating it by the process of heating it to its melting point to create a liquid bond before cooling it to its former stiffness. There are different types of solders available in the market like lead and tin, gold, silver, zinc, nickel, and rosin-core solder. As the name suggests these wires are used for physical soldering operations and also if you wish you can use them in automated purposes like die attach soldering and so on. There is different types solder wire like flux core solder and also it can be a used as a separate flux.

Flux core solder is a sort of metallurgy element that is used while the process of soldering two metals together. Flux is a motionless material that is responsible to prevent the development of metal oxides at intense temperatures. Flux is used in the process of soldering of joining two metals together and the process takes place below 425C. Brazing is another process where flux is used while joining the metal in between the melting temperatures which are above 800 degrees F. Flux used almost in every process like even in Welding, welding is the method of joining separate metals by melting the pieces together while adding a flux in between. With all the above mentioned points, it is clear that flux is filler metal that is used in various processes like soldering, brazing and welding and also it is responsible to prevent oxidation of the surfaces and it prevents the metal from being attached. With the help of oxidation the process of joining the metal deteriorates and that when flux comes in picture it is used to make the process stronger. Depending on the metals you want to join, you can choose from the variety of flux available in the market.

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shaiko said:

When using an external liquid flux source for hand soldering - is it advisable to still use a flux cored wire ? Or would it be better to use a pure coreless wire ?

Click to expand...

At times it is a matter of preference and soldering technique, however when soldering SMD devices it is almost imperative to use both liquid/pen flux and flux cored solder.

When soldering SMDs, some individuals use a technique which applies solder directly to an irons tip and then touching the iron tip to the joint, this essentially boils off the flux requiring the use of additional liquid/pen flux to prep the joint before hand.

Liquid flux also can aid in solder bridge removal.

Here are some discussions concerning the uses rosin/flux cored solder, solid solder and liquid flux:

What kind of solder (rosin cored, etc. lead-free)? What is flux and when is it necessary?

Surface Mount Soldering 101

Inexpensive Tools for Surface Mount Soldering

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Hope the above links answer your questions concerning flux/rosin cored solder and liquid flux.

BigDog

Seriously speaking, I see only few cases where the usage of liquid flux in hand soldering is necessary. In most cases it would be rather a waste of time. In so far it seems obvious that cored solder is the standard. I'm not aware of coreless solder offered for general electronics purposes. I also never felt a need to get it.

It may seem redundant to use cored solder If you are also using liquid flux, but you are probably going to have excess flux anyway. Better too much than too little. Too little flux, and there's a good chance of no connection at all. Too much flux, no harm done. At the worst, it looks messy, and a little solvent will take care of that.