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7 Tips for better solder joints August MR

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Posted by mlehman on Sunday, July 9, 2017 12:25 PM

I'll differ a bit with others here, but it's just what I've found works best for me.

As for getting the work shiny and applying heat before the solder...yes, make sure the iron's tip is tinned. But for most efficient heat transfer, apply just enough solder to form a small ball between the work and tip. This increases the heat transfer quickly, more quickly than simply a tinned tip. Once it heats more, then apply solder in amounts needed to make the bond.

As for silver-bearing solder, yes, it's NOT silver solder, which I have used in arts class back in high school and takes a torch to get temps high enough. I use the Radio Shack stuff, which is 62/36/2. And I use it for just about everything on the layout, except when I need a lower melting point solder for some specific reason.

The silver-bearing solder is stronger than conventional solders, so works great for anything structural. At the same time, I like the fact that it makes my wire connections stronger, as this resists the tendency to pull apart wires when they are tugged at or otherwise abused. And wiring is often abused under the layout, even when being careful. The cost is only modestly more and well worth it IMO.

Mike Lehman

Urbana, IL

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Posted by davidmurray on Sunday, July 9, 2017 9:23 AM

E-L man tom

Dave,

I just went to Home Depot. Just have to read the label because they have several kinds. Personally, I like the paste flux the best, but I occasionally use liquid flux. 

 

  Thank you and the others for trying to help me. 

Radio Shack has now become the source.  Over priced consumer electronics.

Home Depot told me that I don't need flux if I use rosin core solder.  Will try Lowes.  Maybe Princess Auto.

Thanks to all.

 

Dave

David Murray from Oshawa, Ontario Canada
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Posted by dstarr on Saturday, July 8, 2017 12:31 PM

Couple of other things I might add.  Flux is either rosin flux (good) or acid flux (bad).  Rosin flux is a brown goo, sold in little tin cans.  When heated by the iron, the rosin does some kind of chemical magic and releases an acid chemical onto the work.  Acid flux is a liquid, sold in glass jars, the liquid is some kind of acid.  It will reduce the oxide to metal, but the acid will corrode the metal over time.  You want to clean off all the flux after the joint cools down.  Acid flux is so corrosive that it will eat thru the copper etch on PC boards in a year or two, which is why we never use acid flux for electrical work.  Acid flux is for plumbing.  The rosin flux makers claim that when cool, the rosin flux is inactive an non corrosive.  I don't really believe that, and I always clean the flux off after soldering.  Alcohol and a toothbrush will get the rosin off. 

   I do have a little plastic spray bottle of liquid flux.  Qualitek 285 RMA Flux it says on the label.  RMA means "Rosin Mildly Activated".  It ought to be ordinary rosin flux, with enough solvent added to make it sprayable.  It works, although it puts more flux on the top of my bench than it does on the work.  I mention this just to make everyone aware that they do make liquid rosin fluxes, not to be confused with acid fluxes.  

   Simple soldering irons just have an electric heating element that runs all the time.  With the tip in air, say you set the iron down on the bench, the tip will get hot enough to burn the tinning off after a while.  You can buy metal stands to set your iron in, which cool the tip and preserve the tinning.  Or you can unplug the iron when not in use.  Soldering guns do this naturally.  The fancy soldering stations have thermostatic controls that keep the tip at the right temperature, whether in air or pressed against the work.  They were developed to solder semiconductors, which are easily overheated.  For model railroading we don't care much about overheating semiconductors.  Nickel silver rail doesn't care.  But the constant temp feature does preserve the tinning on the tip, which is nice. 

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Posted by SeeYou190 on Friday, July 7, 2017 10:41 PM

Dstarr, that was all very good information. Thank you for the informative post.

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I have used solid core 37-63 solder and rosin flux from a tin for more than twenty years.

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Completely Old-School.

.

-Kevin

.

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by 7j43k on Friday, July 7, 2017 9:53 AM

dstarr

 

 Avoid "silver solder"  that is a different process that requires a lot more heat, like a torch, and special fluxes.  I have never needed the modest extra strength you get with silver solder, and I never did any of the "two temp" work.  "Two temp" means you silver solder the major joints, and then you can soft solder other joints without melting the silver solder.  I don't build brass locomotives, which is the only place the technique might be useful. 

 

 

Note first that "silver solder", as described here, is real silver solder.  It is not "silver bearing solder", like Tix, that you can melt with an iron.  Real silver solder requires a torch. Melting points range from 1170F to 1450F.

I will disagree with the statement that you only get modest extra strength.  As an experiment, I soldered two 14 ga. copper wires, one laid across the other at 90 degrees.  I did one with standard tin-lead solder, and the other with silver solder.  I then attempted to hammer the connection flat.  The tin-lead joint failed almost immediately.  The silver solder joint never did.  THAT is a radical difference in strength--a strength that is rarely needed in model railroading.  But.  A good silver solder joint is pretty much as strong as the metal it bonds.

I have used silver solder in model building just once:  attaching various "pipes" to a casting of an Elesco exhaust steam injector (the low-mount type seen on many GN locomotives).  I used a range of solder temperatures, so that previously attached pipes would stay in place.  I ended up with an assembly that I could attach using tin-lead solder without fear of self-disassembly.

So, yes, silver solder can be very useful in building brass models.  It MIGHT also be useful in assembling switch frogs or point assemblies, though I would be anxious about unwanted annealing of the rails.  That probably wouldn't be a problem for frogs, and you could build the assembly on the bench knowing that it would never disassemble if you then did tin-lead solder when it was being placed.

 

Ed

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Posted by rrinker on Friday, July 7, 2017 9:12 AM

 I've been soldering since my Mom burnt my fingers one too many times - next project I put together I just plugged in the soldering iron and did it myself. Practice makes perfect.

 I hate plumbing with a passion, there's always some crazy problem. Wiring, I'll do all day. However, I broke down a couple of months ago and got a plumbing torch and supplies because the 'repair' to add a shut off for my washer used those press-on fittings and it dripped constantly - those things may be ok for straigh tpipe runs but when there's the weight of a valve and hose hanging off it, forget it. Amazingly I got the correct size parts to put it all together - the hard part was getting the press on connector off. Flux, torch, solder - hey this isn't so hard after all. I did clean all mating surfaces with sandpaper before fitting it together. It's not the prettiest joint I've ever see but considering up to that time I have NEVER soldered copper pipe, it's not a bad job. And it doesn't leak.

 Those tip tinners - they ARE sal ammoniac. Supposedly will eventually eat the plating off the tip, but I used the same tip in my soldering station for over 6 years (recently changed it because I wanted to use a different size - the one I had been using is still good). 

 That Supersafe #30 is the duck's guts. I got botht he paste and gel, but hardly ever use the gel. As I mentioned elsewhere, when soldering rail joints, I will put a dab of flux on the bottom endges of the rail and in the rail joiner, fit the pieces together, and then heat the inside and apply solder to the outside. Sucks right in where the flux was. The end result is a small bead along the outside of the rail joiner where it wraps around the rail base, and solder just visible along the inside of the same joiner - nothing in the way of wheels or flanges. Have yet to melt a tie doing this, and I dont use any heat sinks.

 Those copper scouring pad things are definitely better than a sponge. First one I saw came with my soldering station, and I'll never go back. Quick poke in the pad before and after every joint and I always have a shiny tip on my iron. 

 And therein is the key to getting good solder joints - the surface to be soldered should be clean - the flux takes the last bit of impurities off, but tarnished brass or copper will not solder well, flux or no flux. The other half of the eqution is the soldering irn. A bright shiny tip transfer heat rapidly. A dull, dirty tip transfer heat slowly, giving more time for the heat to flow in the work to places you might not want it - like plastic ties when soldering rails. 

 Keeping things clean is at least as important as actual technique. And having a clean tip encourages proper technique. I am convinced many people see demonstatiosn and understand how soldering is supposed to work, but then they try it on a dirty piece of track with a black tip on the soldering iron, and it doesn;t work. So they hold the iron on longer, melt things and decide they need heat sinks and all sorts of extra solder helpers. Or apply the solder to the iron, and effectively drip molten solder into the joint and then woder why the two pieces just pull apart like they weren;t ever soldered - because they weren't.

                                --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by ednadolski on Friday, July 7, 2017 8:39 AM

I do use the lead-free solder (a tin-silver-copper alloy).   For trackwork esp. turnouts where you may have to file the joints, you do not want to contaminate your work with lead dust & filings which are toxic and get onto your hands, tools, and everything else.   Don't forget that solder manufacturers never intended their products to be filed. The lead-free products are not hard to work with so there is no good reason for unnecessary lead exposure.

The lead-free solders have a higher melting point so I set my iron to 650-750 deg. F.  and use a rosin flux such as the Supersafe #30 (gel).  Just make sure the surfaces have been cleaned (I use #800-#1000 sandpaper on PCB copper surfaces) and you don't overheat the joint by holding the heat on it for too long. Clean the tip after every joint, and as mentioned, keep the iron tip clean with some tip tinner.  A wire scour pad type cleaner is better than a wet sponge since it does not draw off the heat as much.

I do use the leaded solders for delicate electronic components that need the lower temperature, but I am careful to use as little as possible and never file it.

 

HTH,

Ed

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Posted by richg1998 on Thursday, July 6, 2017 10:23 PM

Soldering is a required art, not a necessary evil. A few treat it that way and have issues with proper soldering. That seems to be why some have issues soldering feeders to a rail.

I found the same issue when I started sweat soldering copper pipe.

Understanding heat levels takes some learning

For both, preparation and clean items, not looks clean but cleaned. Many times I found that PC boards eventually would develop a thin layer of corrosion. A Micro Mark scratch bush cleaned it up. Same when soldering feeders to a rail.

I started soldering in 1954 building Heahkits that said in the manual, use rosin core solder. Acid core solder will void the warranty.

When our club layout was built, solder and solder paste with Sal Ammoniac was used. About twenty five years later a few feeders were coming loose. Some say Sal Ammoniac is better for soldering but you have to wash the joint really well. I have seen that in these forums.

The advent of plated tips has been a great advantage. No more filing and ruining a soldering iron tip.

My older soldering gun tips lasted a lot longer when they were plated.

I have found that Radio Shack tip cleaner helps keep a tip cleaner a little longer.

Maybe at least twenty years ago I bought a roll of Cardas quad eutectic solder and by far the best solder I have ever used.

I have used a Weller WLC100 soldering station for some years.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by E-L man tom on Thursday, July 6, 2017 7:08 PM

Dave,

I just went to Home Depot. Just have to read the label because they have several kinds. Personally, I like the paste flux the best, but I occasionally use liquid flux. 

Tom Modeling the free-lanced Toledo Erie Central switching layout.
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Posted by dstarr on Thursday, July 6, 2017 4:47 PM

davidmurray

Good advice from all.

One question, where do I get soldering flux for electrical work??

I dislike mail order.

Dave

 

 

 Radio Shack if you still have one.  Good hardware stores will stock rosin flux (the only kind you want to use in model railroading) as well as 60-40 tin lead solder, soldering guns, soldering irons, and other useful stuff.  Home Despot and Lowes. 

 

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Posted by BroadwayLion on Thursday, July 6, 2017 4:26 PM

davidmurray

Good advice from all.

One question, where do I get soldering flux for electrical work??

I dislike mail order.

Dave

 

 

 

Go to an elecricians wholsaler. They might not want to look at you, but if you go in and ask for flux, at least they will not hand you plumbers flux which is an acid.

 

Boarder States will have it if you are in this part of the country, but then their might not be such aplace near you. Look in the phonebook.

 

ROAR

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Posted by davidmurray on Thursday, July 6, 2017 3:04 PM

Good advice from all.

One question, where do I get soldering flux for electrical work??

I dislike mail order.

Dave

 

David Murray from Oshawa, Ontario Canada
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Posted by E-L man tom on Thursday, July 6, 2017 1:49 PM

Three other tips that I've found to be useful:  1. If you're using a non-heat adjustable soldering iron, keep it hot only long enough to get the job done, then unplug it or turn it off; it avoids the "ugly black" (carbon) buildup on the tip and prolongs the life of the tip. For larger jobs I use my adjustable heat soldering station. 2. Keep the tip "tinned" all the time. If it starts getting black, rub it clean on a damp sponge or cloth and re-tin it. 3. after unplugging or turning off your soldering iron, but before it cools down, clean and tin the tip. I always store my soldering irons in a tinned condition; protects the tip from oxidation. The key:  keep that tip shiny!

Tom Modeling the free-lanced Toledo Erie Central switching layout.
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Posted by richhotrain on Monday, July 3, 2017 5:06 PM

Good stuff.   Yes

Rich

Alton Junction

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Posted by RR_Mel on Monday, July 3, 2017 4:09 PM

Very good info!  That was the way I was taught to solder 60 years ago.
 
If the tip on your soldering iron is a quality tip it will take a good cleaning to renew it to original condition as described in David’s Post.
 
Thank you David.    
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
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7 Tips for better solder joints August MR
Posted by dstarr on Monday, July 3, 2017 3:09 PM

So my August MR came in the mail today.  I read the article on soldering.  The writer skipped a few very important points.  He didn't talk about the need to get the work absolutely bright and shiny clean before starting to solder.  The solder must wet the metal of the work, any dirt, grease, oil, crud, and most especially oxide coating, will prevent the solder from wetting the surface of the work and make it bead up and roll off.  As soon as metal comes in contact with air, (like most all the time) the metal atoms on the surface combine with oxygen molecules in the air and form an oxide coating all over the metal.  Heating the metal makes the oxidation happen faster.  On iron we call the oxide "rust" on copper alloys we call it "tarnish". Solder won't wet the oxide.  The chemistry of flux turns metal oxides back into pure metal.  We flux the joint so that the flux will turn oxide back to pure metal faster than the heat of the iron turns the metal into oxide. 

   Second neglected point.  You have to heat the work and touch the solder to the hot work to have the solder wet the work and form a bond.  If you melt the solder with the iron and touch it to cold work, it won't bond.  Press the iron to the work, wait a few seconds, and then touch the solder to the hot work.

  The author talks about different types of solder.  For model railroad work we want to always use 60-40 tin lead solder.  Or 63-37 tin lead solder.  I have used both and they work the same for our purposes.  63-37 is the ideal eutectic (lowest melting point) alloy, but 60-40 is so close as makes no matter.  Avoid 50-50 tin lead solder, that is only good for plumbing. Avoid the "lead-free" solders, they are unpredictable and it is harder to get a good joint.  Avoid "silver solder"  that is a different process that requires a lot more heat, like a torch, and special fluxes.  I have never needed the modest extra strength you get with silver solder, and I never did any of the "two temp" work.  "Two temp" means you silver solder the major joints, and then you can soft solder other joints without melting the silver solder.  I don't build brass locomotives, which is the only place the technique might be useful. 

   Keep your tip "tinned" at all times.  If the "tin"  (solder actually, but we call it tin when it is on the iron tip)  coating burns off,  the iron or copper or whatever underneath is exposed to air while hot, and it oxidizes black and ugly. At this point the best fix is buy a new tip from the maker.  Starting with a new iron, or a new tip, let the iron heat up, dip the tip in flux, then melt all the solder it will take onto the tip.  This refreshes the solder "tinning" and keeps the "tinning" from burning off.  As you work oxide and assorted crud builds up on the tip.  Wiping the hot tip on the damp sponge will remove the crud. At which point a little more solder to refresh the tinning is in order. 

  If faced with an ugly tip with the tinning burned off, it is possible to recover by scraping and filing the crud off and exposing bright metal.  Dip the newly bright tip in flux, and power up the iron.  Touch solder to the hot tip until all the discolored spots show bright tin.  This works sometimes, other times the tip won't accept new tin, at which point you have to buy a new tip.

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