Silver solder ?

[Chris333]

I was thinking of trying silver solder to make track and was wondering if anyone else has used it this way? I read that you need to use more heat and both parts need to be very hot for it to flow. The iron I use goes up to 700 degrees, but if you hold heat to a PC tie for a long time the cooper might curl up from the fiber board.

Will it work similarly to regular solder with just slightly more heat?

[wcfn100]

My iron was just a little too high once and all my PC ties delaminated.


Jason

[Chris333]

From Wikipedia:

"Hard soldering" or "silver soldering" is used to join precious and semi-precious metals such as gold, silver, brass, and copper. The solder is usually referred to as easy, medium, or hard. This refers to its melting temperature, not the strength of the joint. Extra-easy solder contains 56% silver and has a melting point of 1,145 °F (618 °C). Extra-hard solder has 80% silver and melts at 1,370 °F (740 °C). If multiple joints are needed, then the jeweler will start with hard or extra-hard solder and switch to lower temperature solders for later joints.

Silver solder is absorbed by the surrounding metal, resulting in a joint that is actually stronger than the metal being joined. The metal being joined must be perfectly flush, as silver solder cannot normally be used as a filler and any gaps will remain.

Another difference between brazing and soldering is how the solder is applied. In brazing, one generally uses rods that are touched to the joint while being heated. With silver soldering, small pieces of solder wire are placed onto the metal prior to heating. A flux, often made of boric acid and denatured alcohol, is used to keep the metal and solder clean and to prevent the solder from moving before it melts.

When silver solder melts, it tends to flow towards the area of greatest heat. Jewelers can somewhat control the direction the solder moves by leading it with a torch; it will even run straight up along a seam.

Maybe I should just forget it...  I normally don't have problems with too much heat unless I have to keep "going back in" and re-heating to move something. I was mostly interested in trying silver solder for a stronger joint.

[SkipGear]

The silver solder is a little firmer and it takes higher heat to melt. There are many variations of silver solder content which will determine temperature and strength. I don't know if track takes enough abuse and the strength of silver solder that much more to justify the effort. The only time I use silver solder is in my RC cars in high heat situations like the motor connections on some older really low turn modified motors. I haven't seen a need for it in modern brushless cars. The connections just don't get the abuse that an old amp hog brushed motor could do.

As far as delaminating the PC boards....if you have a good hot iron, it shouldn't be an issue. 700 deg may not be enough. My solder station tops out around 900 deg and it will spot solder very fast to the point that the heat doesn't have time to transfer very far from the parts. If you hold it on too long, that is a different story.

[LV LOU]

 Chris,you don't want silver solder,you want silver BEARING solder.
   Real silver soldering is a welding process,BIG heat,steel needs to be glowing dark orange to get it to work,more like brazing.I use it daily on custom gun parts,motorcycles,and all kinds of stuff I don't want to MIG weld for various reasons.
 Silver bearing solder is regular solder,but it contains something like 5% or less silver.It works just like regular solder,maybe a few degrees hotter melting point.I remember my friend Mike seeing it on my bench once,he rebuilds military electrical equipment at a local Army Depot.I don't remember exactly what he said,but he told me the added silver had something to do with compatibility with silver components, and really was only marginally better than regular solder for conductivity or strength..It does,however,stay shinier than tin solder..I actually have a roll of Radio Shack Silver Solder,if I can find it,I'll give you a melt temperature..

[kalbert]

As far as delaminating the PC boards....if you have a good hot iron, it shouldn't be an issue. 700 deg may not be enough. My solder station tops out around 900 deg and it will spot solder very fast to the point that the heat doesn't have time to transfer very far from the parts. If you hold it on too long, that is a different story.

+1 high heat and fast is the way to go. Most of the people I hear having trouble with soldering of any kind have problems because the iron is too cold, and by the time enough heat gets into the part to melt solder, if it ever gets that hot, the heat has also transferred much further through the part, taking more away from the solder point, and wrecking the insulation/ties/pcb/burning your fingers and they still have a "cold" joint. The exception would be soldering very fine things or using a tremendous amount of heat when it's not necessary. By and large though, if you think you're using enough heat, use a little more.

[robert3985]

Hey "Chris333" (if that really is your name) ,

I hand-lay all of my turnouts and all of my code 40 track on PCB ties.  I've been doing it for 30+ years now and I've built over a thousand turnouts in N and HO scale (mostly N).  I've used all sorts of solder, flux and heating instruments and about 20 years ago I was introduced to both solder and flux that a fellow making brass N scale catenary was using to mass-produce his models.  The flux revolutionized my soldering and I haven't looked back. 

I also use 96/4 Tin/Silver solder bought at the same site as the flux.  I know people will poo-poo my being so adamant about what flux and solder to use when building track, but I guarantee you, you will find this combination is THE VERY BEST you've ever used.

The solder is available here: http://www.ccis.com/home/hn/page5.html

Superior No. 30 Supersafe Soldering Flux (gel & liquid, I use gel) is available here: http://www.ccis.com/home/hn/page2.html

I use two heating instrument for my turnout making, my old, simple 40 watt Realistic wedge-tipped iron, and my American Beauty 250 watt resistance soldering station.

However, I've built hundreds of turnouts without the resistance soldering station, but it sure speed things up and makes my construction (on simply paper templates) much more accurate since I can position, hold and solder simultaneously with one hand.

This solder has no core (is solid) and to apply it with more control, I smash it flat with a pair of smooth flat-nosed pliers, split it down the middle so it's got a two tined "fork" on the end, then use each little solder tine to solder with.  Works well for me.

I have been completely satisfied with both the ease and durability of this combination for both trackwork and building brass and nickel-silver models, although sometimes I use a jeweler's Oxyacetylene torch and solders that melt at different temps...but not so much since I bought my resistance soldering station.

Here's some on-the-bench turnouts I built a while back as entrance turnouts for my Emory Center Siding on one of my layout sections with my solder in the pic:


Keep soldering!

[jdcolombo]

I've used the same solder and flux as Bob on my home-made turnouts, using a 35W Weller iron with a pencil tip.  You will need to use a flux with silver-bearing solder, but with flux, a hot and well-tinned iron/tip, it will work great.  I don't know if the silver-bearing solder is that much stronger, but I've installed six of my hand-built turnouts in switching areas on my layout, and they are working just dandy run by Tortoise switch machines using .033 music wire as the actuating wire (thicker and stiffer than the standard wire).  I wish I had undertaken the hand-laid turnout skill before nearly completing my layout, because the ones I've built (after the first two) are all better operationally than my Atlas #7 or #5 Code 55 turnouts.  I've hand-built some #4's that my EM-1's and BigBoy will run through just fine.  Don't try that with Atlas #5's.

John C.

[Chris333]

Thanks, I'll have to give that stuff Bob listed a try. I haven't had any problems with turnouts, but when I build Z gauge and Nn3 track with a PC tie every inch I might get 1 or 2 joints out of 500 that pop the rail off. I usually don't find it till after the track is painted weathered and ballast scenery down...

[railnerd]

Thanks, I'll have to give that stuff Bob listed a try. I haven't had any problems with turnouts, but when I build Z gauge and Nn3 track with a PC tie every inch I might get 1 or 2 joints out of 500 that pop the rail off. I usually don't find it till after the track is painted weathered and ballast scenery down...

Chris,

Do you think the pops are from thermal expansion, or just a cold solder joint?  Does the PCB delaminate?

-Dave

[mark.hinds]

Bob,

1)  WRT to your 96/4 tin/silver solder (and associated flux) recommendations, is this a strength issue, a lead poisoning issue, being able to use the same solder for both electrical and brass models, or something else?  Being in an open-minded mood today, I am considering trying it, but was looking for a more concrete reason than it being "the very best", so any additional detail would be appreciated. 

2)  I see the company also sells a 60/40 tin/lead solder for "electrical", which implies that they may not recommend the tin/silver stuff for that purpose.  To my mind, track solder joints need minimum resistance, so I have always used "electrical" solder products.  I don't suppose you have any information on relative conductivity of the two (96/4 vs. 60/40) solder joints? 

3)  I see they also sell a "lead-free tip tinner" material.  Is this necessary in your opinion, or could one get by with normal solder / wet sponge tip-tinning techniques?

(For electrical soldering , I have been using Kester 44 solder (with lead), Kester SP-44 rosin paste flux,  and several types of heating devices over many years, all of which appear to work fine). 

Thanks in advance for your response, and apologies to Chris if this is OT,

MH

[robert3985]

Bob,

1)  WRT to your 96/4 tin/silver solder (and associated flux) recommendations, is this a strength issue, a lead poisoning issue, being able to use the same solder for both electrical and brass models, or something else?  Being in an open-minded mood today, I am considering trying it, but was looking for a more concrete reason than it being "the very best", so any additional detail would be appreciated. 

2)  I see the company also sells a 60/40 tin/lead solder for "electrical", which implies that they may not recommend the tin/silver stuff for that purpose.  To my mind, track solder joints need minimum resistance, so I have always used "electrical" solder products.  I don't suppose you have any information on relative conductivity of the two (96/4 vs. 60/40) solder joints? 

3)  I see they also sell a "lead-free tip tinner" material.  Is this necessary in your opinion, or could one get by with normal solder / wet sponge tip-tinning techniques?

(For electrical soldering , I have been using Kester 44 solder (with lead), Kester SP-44 rosin paste flux,  and several types of heating devices over many years, all of which appear to work fine). 

Thanks in advance for your response, and apologies to Chris if this is OT,

MH

The 96/4 Tin/Silver solder answers a number of problems associated with soldering brass & NS parts for models of different sorts.  It, in combination with the Supersafe No. 30 flux "flows" extremely well, meaning if carefully applied (using my flattened-end-forked-solder-end method) a little goes a long way.  One thing you don't want when building metal models is solder "globbies" or excess solder filets around pieces.  This flux/solder combo works great for neat joints in brass, copper and NS.  Strength.  The Tin/Silver alloy is stiffer (less elongation) and markedly harder than tin/lead and works noticeably better at areas of stress such as soldering points to PCB throwbars...which used to be important for me, but now that I'm hinging this area, not so much now. 

Being a long-time ship model builder, when I was doing it professionally, it was known that lead detail parts, when painted, would oxidize to the point that in a few years the lead oxidation would crack the paint and "bubble up".  That's why "museum quality" ship models did not use any lead parts, because lead oxidizes.  I had a few problems when soldering up my first turnouts where I used whatever solder was handy...meaning tin/lead solder.  After three or so years, I noticed that the joints were oxidizing, the paint was flaking off and a couple of years later, the joints were broken or weak.  I don't have that problem with the tin/silver solder and many of my turnouts have been functioning flawlessly for over 20 years. 

I don't worry about lead poisoning when it comes to solder.

As for electrical conductivity, I use the tin/silver for soldering solid copper 22 ga. feeders to the rail foot.  Silver is an excellent conductor and I put a 7" feeder on every piece of rail, no matter how short it is.  As a hard rule, I do NOT trust NS rail joiners to conduct electricity, but use them for mechanical alignment.  NS is a really poor electrical conductor (very high resistance) and is actually a very poor choice from an electrical standpoint to use as rail for model railroads, except its oxide is conductive.  But, it's what we're stuck with.

As an aside, Nickel Silver doesn't have any silver in it.  It's made of an alloy of 60% copper, 20% nickel and 20% zinc.  Its electrical resistance is so high that one of its uses is for certain types of electrical heating elements.

Additionally,  the tin/silver solder has lower resistance (better conductivity) than the tin/lead alloy.  However, the tin/lead alloy has a markedly lower melting temperature, which would be better for solid state, SMD devices.  I'm thinking that's why it's recommended for electrical and electronics work.

I use their tip-tinner too.  Yes, it's an easy way to keep the tip of your iron bright, and out of long habit, I won't solder a joint unless the tip of my old iron is bright and clean.

Supersafe No. 30 flux makes soldering just about anything together in the model railroading world possible.  The heat of soldering neutralizes it and I have never had a corrosion problem with it, even when washing the joint would have been prudent, but I didn't do it.  A little goes a long ways, and I've used up one bottle of it over the past 20 years, and I'm about halfway through with my second bottle.  I use the gel, and it's become fairly runny now that it's getting old, but it still works just the same.

Here's a table to compare the various properties of different alloys of solder:  http://alasir.com/reference/solder_alloys/

Hope that addressed and answered your questions. 

[peteski]

To add to bobs explanation, 60/40 solder (actually 63/37) solder is used as it has special properties. It is a eutectic alloy.  Read more at http://en.wikipedia.org/wiki/Solder#Lead_solder

Using that type of solder makes it much easier to prevent cold solder joints (which are foten used when other solders are disturbed (by moving either of the soldered surfaces) while the solder trasnforms from loquid to solid.

As far as oxidation goes, I have not noticed that problem with lead solders. I use them on electronics and on models, and even some 30+ year old solder joints I have made (both, left bare and painted) do not show any problems due to oxidation.