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Bonding wire to underside of turnout frog

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  • Member since
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  • From: Clifton Park, NY
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Bonding wire to underside of turnout frog
Posted by Benjamin Maggi on Tuesday, November 07, 2017 9:26 AM

I have heard various conflicting reports on whether it is possible, and even "easy," to solder power wires to the underside of Micro Engineering turnout frogs. Some say "get in, get out quick and you will be fine" and other have said "no matter how much I file/polish the bottom of the frog, I cannot solder a wire to it. Obviously, there must be something going on.

I had an interesting idea. I have lots of small 2-56 bolts and screws, some an 1" or more in length. I was wondering if there was something like an epoxy or JB weld which I could use to glue a screw to the bottom of the frog (once it was suitabled filed to reveal bare metal)? Of course whatever I use would need to conduct electricity. Has anyone ever tried this?

I would need to drill a hole in the benchwork for the bolt to pass through, but once below the layout I could then wrap a wire around it and solder there, or use a ring terminal or something else.

Modeling the D&H in 1984: http://dandhcoloniemain.blogspot.com/

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Posted by BigDaddy on Tuesday, November 07, 2017 9:31 AM

Why not drill and tap? 

edit  There actually are electrically conductive epoxys.  Not much surface area between the end of a screw and the frog, but I suppose it would be possible.  I still vote for my 1st choice

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by 7j43k on Tuesday, November 07, 2017 9:39 AM

If you clean the bottom of the frog well enough for epoxy to bond, it should be clean enough to solder to.  Unless it is "non-solder" metal.  The bond will be much better, too.

I was/am apprehensive about sticking a soldering iron onto the back of a track switch--all that heat going wherever it pleased, and all.  So I use a resistance soldering rig.  There is only heat when I activate it.  And it is localized at the connection of wire and frog, just where it needs to be.

I have soldered feeder wires to the bottoms of all of my switch frogs AND point rails, and it worked nicely.

 

Ed

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Posted by RR_Mel on Tuesday, November 07, 2017 10:14 AM

I would try to drill and tap a hole in the bottom of the frog.  I would drill a #57 hole in the bottom of the frog about .06” deep and use a #0-80 bottoming tap for a #0-80 brass screw.  That should be enough threads to hold the screw as a contact.  The brass screw would be easy to solder to.
 
I’ve tapped code 83 rails before using that method and it worked OK.  The holes went in a bit deep (had the stop set wrong on my drill press), the threads showed so I just cleaned off the threads with a file and I’ve had no problems with it.  The rails I drilled were for my turntable and I didn’t want to heat up them up to connect power.
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by trainnut1250 on Tuesday, November 07, 2017 10:44 AM

Benjamin,

I have soldered about 50 frog wires to ME switches - yes they are are up the scale in soldering difficulty. Cleaning the solder point is difficult due to the recessed nature of the solder point. If you haven't tried using a super flux (non corrosive) you might try that. I cut the plastic back on the underside of the solder point to prevent the heat of the iron from melting the plastic and ruining the joint with burning palstic residue.

As for conductive glues - I have used a silver bearing epoxy designed for circuit board work. Worked well but was pretty pricey $17 for a pair of small tubes (like .25 OZ). If you go this route make sure the stock is new. I have bought a dried up packages (I'm guessing due to slow turn over).

Drill and tap might work but would be a lot of hassle.

 

Guy 

see stuff at: the Willoughby Line Site

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Posted by BroadwayLion on Tuesday, November 07, 2017 10:58 AM

LION has 48 wheel pick-up.

 

Him not bother to wire double crossovers or slip switches.

 

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by Benjamin Maggi on Wednesday, November 08, 2017 2:14 PM

Thanks to everyone for their helpful advice! Smile

Modeling the D&H in 1984: http://dandhcoloniemain.blogspot.com/

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Posted by dante on Wednesday, November 08, 2017 9:17 PM

I do not have up-close, personal experience with ME turnouts, but is it possible that the guardrails adjacent to the frog are electrically connected to it? That is true on my W/S turnouts; therefore, I just drop a feeder from one of the frog guardrails and do not touch the frog itself.

Dante

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Posted by Marc_Magnus on Thursday, November 09, 2017 10:27 AM

One aspect of soldering small points in small area is never or rarely explained and explored.

So if necessary I will give you these small advices which I hope could help you.

Nickel silver used to make models rails like ME or brass are subject of oxygen alteration and humidity which is corrosion; on iron this corrosion is impressive and we know it as rust.

This corrosion is a barrier for a good soldering job.

Even if nickel silver shine on first hand, after a while it's surface is corroded and we need to "wash" this tin corrosion surface to make a good soldering job.

For brass and nickel silver, polishing them, is enough to obtain good soldering surfaces. 

First rule, a clean surface, use some brush wire or even polyester brush used for weathering or a piece of wool the same used to wash our dishes to clean brass or nickel silver in small spots.

You can glue these things on a small piece of wood to go on small spots; I didn't advise you to use sand paper because of the sand dust which can altered the future soldering work.

If you use weathered track, you must clean of a spot from the weathering to obtain the natural nickel silver: a small polish disk in a Dremel do the job, after use piece of wool as I mentionned to finish the cleaning; don't touch the area with your fingers.

The use of solder flux is sometimes necessary but don't use acid flux especialy the ones with clorid zinc, the residue are extremly difficult to wash; paste flux with non corrosive additive are cleaned with toothbrush and alcool.

Soldering is made with a good soldering iron  and for small spot with a fine pen tip; if you  are able to use a soldering iron with variable temperature capabilities like a  Weller station, it's a best;  a 25 to 45 watts soldering iron is normaly enough to do your job.

For small spot use fine solder around 1mm diameter or even smaller, fastrack offer very fine solder and non corrosive paste flux  www.handlaidtrack.com

Even better if you are ready to make a lot of soldering for track and brass pieces, resistance soldering is the next and best step to use; this system didn't heat the whole piece  but just the spot you need to solder; most of the brass models are soldered with resistance soldering hardware.

As an ironworker by formation, if you need to solder something there are three rules,

a clean surface     enough soldering temperature    the appropriate solder and flux.

You need to heat the area enough to flow and glue the solder on the support, flux help this process.

The tip of the soldering iron must be clean, perfectly clean.

The tip of the wire must be clean and already thinned with solder.

If you can reach easily the future spot to be soldered, you can thinned it also with a small amount of solder.

A small amount of solder on the tip of the soldering iron and you are ready to go.

Put the thinned wire on the area, put the pen of the soldering iron  and melt everything with solder....."voilà" the wire is soldered on the rails.

If there is places where heating must be provided, like plastic or other already soldered pieces, a aluminium tip just next the soldering area keep the heat from this area, even a small piece of tissue  or paper soak with water next to the place to be soldered is an excellent heat keeping.

Try and error are learning points to good soldering job, so try it on some scraps pieces of rails or brass to learn and understand how the relation between solder, flux and soldering iron work. 

But anyway the first rule is a clean surface, if the support  is greasy wash it  first with denatured alcohol and polish it after as mentionned.

Hope this help.

Marc

 

  • Member since
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  • From: Clifton Park, NY
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Posted by Benjamin Maggi on Thursday, November 09, 2017 10:39 AM
Thank you to everyone who responded. I will try buying super small solder, which I am sure will help.

Modeling the D&H in 1984: http://dandhcoloniemain.blogspot.com/

  • Member since
    May, 2004
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Posted by 7j43k on Thursday, November 09, 2017 11:11 AM

Benjamin Maggi
Thank you to everyone who responded. I will try buying super small solder, which I am sure will help.
 

I recommend getting a pound of .020" (half millimeter) flux core solder.  It's about $30, and will last a lifetime of model railroading.  Perhaps more.

There is finer solder, but the price starts going up.

 

Ed

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