Originally Posted by
the incubus
It would be a good idea to try soldering something using your technique and then try it how I explained and see which you prefer. If be interested in seeing pics of them compared.
Having been doing soldering (off and on - not every day) since 1963, I know what I prefer. I would apply heat to the workpiece and let the solder melt it when building the slot car chassis. I still do that on the rare occasion when sweat soldering copper pipes or larger items.
But for RC stuff I prefer an appropriate amount of solder on the iron applied to pre-tinned wires and generally pre-tinned components (for instance, I don't bother to pre-tin the posts on an RX-8 because it is just not necessary with my technique).
My take on it is this: It you apply heat to the joint and solder to the joint, the heat you apply to the joint will start moving into other parts of the materials while the joint is transferring heat to the solder to melt it and flow it in.
If both halves of the joint are pre-tinned, putting the small additional amount of solder on the iron means it is already not only at, but above melting temperature. When the iron is applied to the joint, it only has to transfer enough heat to get the joint materials up to temperature and let the molten solder flow into the joint, not the additional required to melt room temperature solder.
Further, since I apply flux to the joint materials and to where I am going to touch with the iron, the flux cleans the solder and iron tip in the instant the iron is applied to the joint resulting in faster heat transfer because the solder on the iron conforms to the joint surface much better than any flat surface of an iron can. This way takes less time, not more (for me anyway) since I am always soldering pre-tinned components.
I've watched many RC guys solder using the classic technique. It usually takes them many times longer to complete a joint that it takes me. Unless you are working on battery terminals, RC soldering essentially only involves small joints between wires and electronic components, instead of constructing stuff out of large items that take a lot of heat to solder. So I'll stick with the solder-on-iron technique for my RC stuff. I still use the "classic" technique for other soldering needs as appropriate.
Originally Posted by
the incubus
Cool use of the ferrules on your leads but what I see in the pics only the center one looks close to perfect. The one on the right appears to have crystallization which is indicative of a longer exposure to heat from the iron and the left one appears to be a bit on the cold side. When you apply solder on the iron the components generally take longer to accept the solder, which is why you find applyind flux onto components more than effective.
BTW, all three of those joints are fine - I think you were extracting more information than was available in that slightly out-of-focus image.
Originally Posted by
marine6680
I feel that putting flux on stranded wire directly is both good and bad. Because the flux flows into the wire well before applying heat, which allows it to work better... But liquid flux can seep into the wire too far and allow solder to flow under the insulation.
I use paste flux, not liquid.
Originally Posted by
marine6680
Applying heat to the components, and then touching the solder to the components is the better method. It allows the solder to flow toward the heat, which it does better than flowing away.
Which means it takes longer to complete the joint (because the heat has to flow from the iron, to the joint components and then to the solder) thus allowing more heating of components down the line. I am sure it must take me more time overall for each joint given that I pre-tin and flux all my components. But the iron spens less time heating up the parts and the nearby stuff remains cooler.
I will not claim that the solder-on-iron technique is better for un-tinned components, but for RC work I
never attempt to solder un-untinned, un-fluxed components together.
Never, ever. So all I need on the iron is the little bit of solder to fill/bond the components and I find having it on the iron works out very well.