The Solder Shop Q&A
#1
I've brought this thread and its companion thread "The Solder Shop" over from the old Gauge's Academy. Both are threads originally by Randy Cline (rcline over there) with the Solder Shop being solely his work, while the Q&A section is by both him and other responders. I was unable to copy the entire format from there, but have added the posters' credits (screen names) at the end of each entry.

"The Solder Shop Q/A "


Q. What part does flux play in the connection of solder to the metal where they bind together? (Posted by yellowlynn)

A. Flux promotes cleaning of the metals while preventing air (oxygen) from touching the metals while the metals are hot. When the metals are hot, oxidation (rust) starts immediately, flux helps to prevent this. (Posted by rcline)


Q. I was wondering about when you solder track how you keep the ties from melting? I get it just hot enough to run the solder and look down and the ties went with it! (Posted by who dat73)

A. What I do, and you might be able to do also, I snap the track loose from the rails themselves for about 4 ties back. Then I put a spacer between the rails and the ties to keep them seperated a little ways, after making my soldered connections, and letting the joints cool, I snap them back. Also I use a little heat sink (can buy at R.S.) to keep the heat from traveling down the rails to the point where the track is still snapped to the ties. Give that a try. The heat sinks that I use are spring loaded clips made of aluminum, which absorbs heat really fast, so be careful not to burn your fingers when removing them. (Posted by rcline)

COMMENT: I'm certainly no expert and I look forward to reading the rest of this tutorial, but my experience is that heat sinks drain heat away, making it take longer to properly heat the joint, thus melting the ties. Best way to avoid melting ties is to work fast. Keep the tip clean and hot, tin both the wire and rail, and then just hold the wire against the rail and heat. Ought to take like one second. However, if you do melt a tie or two, remove them and replace with others. I use a chisel blade to remove the cast on spike detail on the side away from the aisle and just slip them into place, glueing them. The fact that they are useless for holding the rail in gauge won't matter as you shouldn't have to replace more than two. (Posted by Gary Pfeil)

COMMENT: You are sort of right. The idea of using a heat sink to prevent the heat from spreading any farther down the rail or up the wire or if you are soldering the leads (or pre-tinning) to a component. I place my heat sinks at about the the third tie down. A proper soldered connection should not take any longer than about 2 to 3 seconds (if pre-tinned only about 1 to 1-1/2 seconds). In that short amount of time the heat will only travel about 1 to 1-1/2 ties down the rail (if pre-tinned, not even that far). I, myself, have never gotten my heat sinks hot, but I still use them as a safety factor. You are right about pre-tinning everything first. (Posted by rcline)

COMMENT: I use rail gauges for heat sinks. That way, even if you soften the ties, when they harden the rail will be in the right place.
If you have trouble finding rail gauges, the Kadee coupler height gauges have the same formation on the bottom. (Posted by 60103)

COMMENT: I want to give a bit of warning to everyone about solder. The standard solder has always been either 50/50-radiator solder, or 40-60 which is covered in the "solder shop". Last time I was looking for solder to use for electrical soldering at work at Home Depot, I discovered they don't carry any solder containing lead anymore. Their electrical solder is 95/5 which is 95% tin and 5% antimony. This is a solder that I have used for years in refrigeration, because pipe joints made with 50/50 or 40/60 in a refrigeration system will only hold until the unit is started up and pressures come up to operating levels at which point everything blows apart! It is a lot stronger than lead solders, but not as strong as silver bearing solders. The down side is that it melts at much higher temperatures. 40/60 rosen core solder is still available at industrial hardware supply stores. When you go to buy solder, look closely at the package to make sure you are getting what you think you are getting. (Posted by Russ Bellinis)


Q. I've heard that wet tissue paper is good as a heat sink. Makes sense to me, since water has a much higher specific heat than any metal? (Posted by farnham)

A. When it comes to removing heat, the most efficient thing around is water. The best heat sink you can get to keep ties away from the solder joint from melting is to put a damp wash cloth across the rails just a little ways up from where you want to make the joint. You can touch the soldering iron to the wash cloth and it will cool it off, but heat won't get past the wash cloth until it is pretty much dried out! (Posted by Russ Bellinis)

Q. Can pewter be soldered or should I use a glue? Which would be stronger? This is for vehicles made from cast pewter parts. (Posted by inkaneer)


A. As with all metals, there has to be a way to solder, braise or weld pewter, but I don't think you will be able to use the standard tin/lead available. Dependent on the size of the parts, I'd use CA glue, just be sure they are free of any oil by cleaning them with water and detergent first. (Posted by ezdays)

COMMENT: This might help some of you. I have N scale and when I solder rail joint I have a stainless steel feeler gauge ground down to fit between the rails and ties, it works rather well to keep the ties from melting I also use a alum. block which I machined to fit the rails and absorb the heat. (Posted by pennman)

Q. How do you solder small joints that you want out of site? For example, say I am making a catenary bridge made of brass, and I don't want there to be a big nasty glob of solder at each joint. How do I apply only a little solder? (Posted by green elite cab)

A. Pre solder your wire ends.
1. Clean both ends of the wire
2. Pre solder your wire ends(sweat the wires) separately.
Depends on wire size I tend to use a thinner solder for thinner or lighter materials.
3.When both ends a chromed with solder, set them in place where you want them, apply a light amount of heat with a soldering iron and both should join nicely.
You may want to clamp them if your not sure you can hold them.
After completion just take a little sand paper and smooth the joint. (Posted by pennman)


COMMENT: The one thing that will make your soldering easier and make a good clean joint is to use flux. I apply a small amount of liquid flux to both joints and as others have said, pre-tin the wire or whatever is being soldered. The flux cleans the joint and makes the solder flow and adhere better. You wind up using less solder and getting a better-looking and more secure solder connection. If you were soldering two pieces of flat brass together, put flux between them, hold the iron on top of the joint and put the solder next to it. When the joint heats up, the flux will allow capallary action to suck the solder up into the joint. (Posted by ezdays)


Q. Would like to know if there is an advantage to soldering the joint where 2 sections of flextrack meet? I been using the rail jointers with flex track but find that it is difficult to align flextrack on a turn so I have a smooth turn. Thought the soldering would help my turns. What are your thoughts? (Posted by Jeffs Railroad)

A. If you are using Atlas flex, then solder the joints while the two pieces of rail are straight, and then lay them on the curve. That should help eliminate the kinks you get when using rail joiners only.
If you are using some other sort of flex track (like Micro Engineering), you need to "overbend" the rail a little more so the curve comes out smoother. (Posted by MasonJar)


COMMENT: I don't know what everyone else does, but I solder every joint where two pieces of track come together and I'm not using an insulated joiner there. I usually solder them after the track is in place, but in the case of flex track on a curve, I'd solder it first. (Posted by ezdays)

This is the end of the topic. Thanks to Randy Cline for his work and to all who provided the questions and answers.

Check out the companion piece to this thread, The Solder Shop, HERE
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