Model Railway Forum

Hi folks,

If you're on several modelling fora you will probably see this post several times - apologies! And I hope I've posted this in an acceptable group!

I'm looking to canvas views (and advice) on soldering flux as there seem to be a lot of conflicting opinions and 'facts' (not sure whether the quotes are justified).

There are several types of soldering that I want to do: electronics, track (on PCB), brass kits, white metal kits and, occasionally, track on plastic sleepers (e.g. turnouts).

So far, it seems that for electronics, simple multi-core solder is fine, but liquid flux won't hurt (so long as it's not acid?).

For all the other jobs I've had advice that I should only use liquid flux, that I can use multi-core, that I can use both, that acid flux will attack a joint unless washed and that rosin flux (as in most multi-core) can leave a film which doesn't take paint very well.

Any advice gratefully received!

Pete

Whilst I do have flux in both liquid and paste form, most of the time I forget to use it, or haven't needed to. As long as the parts you are trying to join are clean, I find that tinning them and then joining them works fine using flux cored solder.

This has worked for me on electronic components to PCB, general wiring and rail to copper sleepers. I haven't tried assembling any white metal kits, but I understand that if you are going to solder those, you generally need low melting point solder. These won't have a flux core, so some flux will be required but I have no experience to be able to suggest what might be best in this application.

I always used to stick with multicore lead solder and occasionally some solid rosin flux. Then, more recently I discovered this gel paste flux:
https://www.amazon.co.uk/Rosin-Based-So ... B0C3VWZD1C
and I'm a big convert. A tiny bit of this smeared on first and the solder always flows and sticks first time. It's great stuff and makes soldering simple.

Iv always found soldering simple. Except when doing white metal kits. then I use a flux that has Phosphoric Acid. And the lowest melting point solder I can find.
But I have found that Araldite is very good for white metal kits as well. I have kits made years ago using Araldite and they are still strongly holding together. Nothing falling off them yet.