fitting dcc droppers to track....what size iron

[pheaton]

Hi All,

 

Im trying to fit extra droppers to my layout but my iron works at 300, I can raise it to 400 but it burns the tips out quite quickly, what's the best iron temperature and wattage for soldering droppers? also, do people find it easier to use single or multicore wire?

 

Thanks

 

Simon

[Tricky Dicky]

I currently use a cheap Maplins 40W iron with supposed temperature control but I could not tell you what the temperature is set at since it is a knob control with a coloured scale going from green -cool, to red-very hot and I find setting it at 3/4 turn is right for me but i think if you can set temperature about 365C is about right.

 

When you say the tips are burning out at high temps are you referring to the tip or the element? I suppose prolonged use at high temp will tend to take it out on an element over time but tips tend to get damaged more by abrasions. Most modern irons have copper tips coated by iron carbide. If you have cleaned the end of the tip with a file or emery cloth that coating abraded off and initially with the copper exposed you will find it solders very well but over time you will observe a cavity forming due to the action of the flux. Brass bristled brushes are about the toughest you can employ to clean tips. Of course the the secret is not to allow the tip to get cacked up with oxides which means frequent wipes on a damp sponge and re-tinning of the tip whilst soldering.

 

Wattage and temperature do not necessarily equate. When soldering as soon as you touch the tip to the metal being soldered heat transfers from the tip to the metal, how quick the tip replenishes that heat is down to the wattage the higher the quicker and the quicker you solder. This is important when soldering to rails whose bulk has the effect of a heat sink drawing heat along the rail, this is what melts plastic sleepers. Low wattage irons need to be held on longer because they struggle to get the area of soldering up to fusing temperature thus allowing more heat to travel along the rail. A high wattage iron will allow you to deliver the heat quicker but more importantly localise the heat where you want because the whole process is quicker. Fusing of solder only takes place if the metal being soldered achieves fusing temperature in other words it is the heat in the metal that melts the solder. My maxim is you can have too little power but you can never have too much!

 

Richard

 

PS:  The bulk and diam. of the tip also have a bearing on the heat transfer - the wider the tip the more transfer. Mine is the fairly standard 2.3 wide tip

Edited May 19, 2020 by Tricky Dicky
Missing info

[pheaton]

Hi,

 

thanks for that this is the maplin soldering station, and basically its eroding the tip at 400 the tips are visibly damaged at the end of a session. been looking at a Weller 40w iron and im interested to see how this gets on but before that ill raise the tip to 350 and see if that's any better.

 

thanks again

Edited May 19, 2020 by pheaton

[RFS]

2 hours ago, pheaton said:

Also, do people find it easier to use single or multicore wire?

 

It's really your choice. If it's a static layout where the wires are not going to get moved about then single core is fine. I use 1/0.6 on my layout for droppers as I find that is easier to solder to the side of the rail. 16/0.2 is somewhat overkill for droppers that are short, and can not only be more visible but also more difficult to solder to the rail. 

[Brian]

Whenever possible try not to solder droppers (regardless of their wire size) to the rails outer web area. They look unsightly!   Instead and for an almost invisible look, solder them whenever possible to the rails undersides before laying the track.  Passing them down to below baseboard via a centrally drilled hole between rails and a sleeper pair or if preferred by two small holes in line with the outer edge of the rails. 

I recommend at least a 25 watt iron and if possible a larger wattage, but fitted with a suitable sized bit.   

Edited May 21, 2020 by Brian

[brossard]

I solder the wire to the underside of the rail as Brian says.  In fact I just finished laying my track with droppers a couple of weeks ago.  Clean and tin the rail and tin the wire, apply flux.  Flux and apply the iron to the rail/wire.

 

I don't understand the problem with soldering though.  I think my Weller stand alone iron is 25W.  I did have trouble with black bits which don't conduct heat well.  Since changing the bit and being scrupulous with tinning and cleaning, the bit has behaved itself. 

 

I also have a Weller soldering station with tip temp feedback.  The bit on this stays shiny all the time.  Eventually the thermocouple (or whatever) in the tip goes TU and then I have to change.

 

Perhaps the issue is with solder and flux.  For electrical joints I use 60/40 solder (lead/tin but can never remember which is which).  This melts at ~ 188 C IIRC.  No lead flux is a waste of time for me - it doesn't flow.  For flux I use rosin.  I don't like cored solder because if you have to go back to joint, the flux has gone.

 

John

Edited May 21, 2020 by brossard