Wave soldering - using Pot solder

Question

I understand the wave solder process for pin soldering, I have seen videos and read literature while pot solder is used for tinning purposes.

My question is about why we requires the solder to flow.

1- wetting process: Q: why the wetting requires the solder flow in the Nozzle q: why the nozzle full of solder but not flowing would not wet, based on wave flow needed?

Q: how could we use small pot to solder edge pins connector to pre-built board without hand solder and without damage if I can get the hot solder in the nozzle in a small pot, but not flowing, but remains at the temperature during the soldering period?

or is that not possible without the flowing process in the nozzle?

Answer 1

To do dip soldering you first flux the board (for example by dipping it into liquid flux). There is no rush to solder after this, you can even let the flux dry. It helps if you can preheat the board to approximately 100°C.

The solder should be at the proper temperature before starting. Skim the dross to one side, leaving a shiny surface, then 'roll' the PCB into the solder starting at one end until it is flat in the solder, then lift the part up that was lowered first. Total time should be a few seconds. There will be much sizzling as the flux boils off. If the solder is too cool it won't clear the pins well. If it is too hot you can damage parts or the board itself.

Answer 2

It sounds as if you want to do what is called "dip soldering".

This is where you have a pot full of molten solder. You spray the bottom of the PC board with Flux, then carefully lower the board into the molten solder.

This technique can be reliable but it takes a lot of practice to be really good at it.

You can purchase solder pots in various sizes. Choose one that is large enough for the biggest board that you want to do.

Answer 3

As to "why must the solder in the nozzle flow for wave soldering" - because in wave soldering the liquid solder is ABOVE the sides of the nozzle by a sufficient distance for the leads to clear the solid nozzle while the liquid solder touches the bottom of the board as it rides over the nozzle. Without flow, that does not happen - the solder sinks to the level of the nozzle or lower. Flow also somewhat automatically deals with removing dross, etc from the active soldering area. The wave only needs to be wide enough for the widest board (it can do any length), as opposed to a pot that needs to be large enough for the largest board.

I'm a little dubious about dip soldering an additional connector to a pre-assembled board - you may lose parts or overheat them.