Soldering G-scale Track

B

Bob Watson

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I have just purchased new Weller 70 watt Solder Iron and am having trouble soldering feeder lines to G-scale Brass tracks. I am using 63-37 tin lead rosin core solder wire (no flux). I am using 1/8 inch flat head and heated to 650 F but can't get the solder to stick. Can someone give me some good advice?
 
70 Watts is quite low.

And soldering outdoors is difficult too....
 
I use the Weller 350 watt gun and it just makes it soldering the brass rail.
Brass conducts the heat from the soldering gun real fast. I keep a wet rag to cool the rail after soldering and drag it from 6 inches away towards the joint to cool the rail/solder joint slowly.
 
Best advice is use flux, sounds like you are getting what is known as de-wetting that is mostly caused by the presence of oxidization.
To clean that off use a fine grade abrasive, a scouring pad works well, this will leave a clean surface onto which you apply your flux.
The main purpose of flux is to chemically clean the area you want to solder to and aid solder flow.
Mechanical clean and then chemical clean should result in a good solder joint.
Also it is important that the area be heated to the correct temperature to allow solder flow, to achieve this you have to build a solder bridge which is just some solder between the iron tip and the joint area.
This aids thermal transfer and again solder flow.
With a small iron that may take some time.
Do not use the plumbing type flux the electrical type is the best.
The rosin core is flux but it is not much good for large areas as there is really not enough of it (it is designed for PCB and general electrical work) to get better resin to flow clip off the end of the solder each time you go to solder a joint.

I use a small blow torch when I am soldering outdoors as I can get a lot of heat into a small area quickly, to stop the sleepers melting I pull them away from the area (I use flex track) otherwise remove the sleeper and slide it back under after soldering. You can also use bulldog type paper clips as heatsinks to reduce the prospect of melting. The trick with doing this is get in fast and get out fast.
 
You need bigger than that..

If there is a slight breeze, it won't work.

If the track is sitting in (even slightly) damp ballast, it won't work.

I would suggest something around 120W would be better for this.

PhilP.
 
With soldering large pieces of metal absolute cleanliness of the metal is critical! Mechanically polish the brass until it is shiny-bright clean - fine steel wool or a rotary wire-brush tool in a dremel (or similar) is good for that.

You will also need a good metal flux. This one from Screwfix is good.

Lastly, with code 332 brass rail you will need a lot of heat. A 70W soldering iron might do the job if you have everything else just about perfect, but is probably not the best place to start.... you'd need a higher rated iron with a big tip.

On the rare occasions when I have personally needed to solder to code 332 brass rail I have used a resistance soldering unit rather than a soldering iron, and I know that others have had success using butane gas torches .

Lastly, instead of soldering directly to the rail, have you considered using rail clamps around the track and soldering eyelets to the end of your feeder wires which are then put under the screws on the rail clamp? The photo below is just one example, there are a number of different rail clamps on the market.

IMG_2639.jpeg
 
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A slightly easier way with less heat required is to solder to the webb of the rail less heat required. If you drill a small hole in the webb and solder the wire into this that also works well. But previous advice re larger iron ir using clamps and tags as suggested by Software Tools very sound advice. I have used that method, another with clamps is to create a soldered ring at the end of the wire to be used by the screw, ensure well cleaned of flux before fitting.
 
Software Tools said:
With soldering large pieces of metal absolute cleanliness of the metal is critical! Mechanically polish the brass until it is shiny-bright clean - fine steel wool or a rotary wire-brush tool in a dremel (or similar) is good for that.

You will also need a good metal flux. This one from Screwfix is good.

Lastly, with code 332 brass rail you will need a lot of heat. A 70W soldering iron might do the job if you have everything else just about perfect, but is probably not the best place to start.... you'd need a higher rated iron with a big tip.

On the rare occasions when I have personally needed to solder to code 332 brass rail I have used a resistance soldering unit rather than a soldering iron, and I know that others have had success using butane gas torches .

Lastly, instead of soldering directly to the rail, have you considered using rail clamps around the track and soldering eyelets to the end of your feeder wires which are then put under the screws on the rail clamp? The photo below is just one example, there are a number of different rail clamps on the market.

View attachment 340085
Click to expand...
Yep, as others have said, soldering anything in brass is an issue because brass is too conductive (in terms of heat) and the heat quickly dissipates.

For track, mechanical is far easier - and works just as well
 
korm kormsen said:
after i tried to solder fishplates to rails, i decided to change to mechanical connections. :mad:
and i never looked back.

View attachment 340099
Click to expand...
Thanks for the tip on rail clamps - I never considered them. My Soldering iron reaches 760 F and I thought that would be enough but I will try using flux but the rail clamps may be best. The solder wire that I use melts at 361 F which is low.
 
Bob Watson said:
Thanks for the tip on rail clamps - I never considered them. My Soldering iron reaches 760 F and I thought that would be enough but I will try using flux but the rail clamps may be best. The solder wire that I use melts at 361 F which is low.
Click to expand...
You can solder the lead to the tag, in the nice warm recesses of your workshop :cool::cool: It makes life much easier and more comfortable ;);)
 
In days of yore when I bonded all my rail joints I used a 75W iron and resin cored solder without any problems. As other have said, the rail needed to be scrupulously clean. I used a square section needle file.

DSCF0009.0(1).jpg

Rik
 
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