Tinning

[ol vern]

Ok, I give up :surrender: what is the secret to tinning? I can't get solder to flow and tin a surface.
All I get is a big ball of solder that runs right off whatever I am
trying to tin.

 

[paulvallandigham]

Did you flux the surface to be tinned before applying the solder?? That IS the "Secret". :thumbsup:

 

[Zonie]

ol vern:

The surface must be absolutely clean and free of any oxidation or oils.
Oxidation includes rust or any bluing that might be present on the surface.

Flux used for soldering is an acid or "killed acid" who's job is to remove the faintest trace of oxidation but if it is used on a contaminated surface it often will not work well because it is meant to remove traces of the contaminants, not all of them.

If you are working on a bare steel surface the type of flux you use has a great deal to do with how well the surface will accept solder.

If you are using a rosin core solder, made for electrical wiring it won't work on a steel surface. Rosin flux is the weakest type of flux.

There are several solder fluxs made for steel and they will contain either zinc chloride or Ammonium chloride. They usually come as a paste in a little can or jar and although some of them look greasy they are not.

These are mildly acidic and they must be removed after soldering or they will rust the surfaces.

Flux of this type is available at most hard ware stores.

To tin a steel surface, first sand it with a good very fine abrasive sand paper. Do not touch the sanded surface with your fingers as they have oil in them.

Next, apply the flux to the surface and heat the body of the part gently. DO NOT apply a flame directly to the fluxed surface.
Also, do NOT apply the flame directly to the solder.

Every little while, touch the surface with the solder and hold it there for 5-10 seconds. When the surface is hot enough the solder will melt.

Another mistake often made is to overheat the part or the surface trying to make things happen faster. Applying a flame directly to a fluxed surface or the flux will overheat it and it will loose all of its abilities to remove the oxides from the surface. In fact, applying the flame directly to the flux will burn it, making it the contaminate that will prevent the solder form sticking to the surface.

When the solder on the heated, fluxed surface starts to melt, move the solder around, spreading it evenly. If too much of it melts forming a bump, use a clean wire brush to brush away the excess solder.

When the surface is evenly coated with a thin layer of solder, let it air cool. Do not apply water to cool it.

Properly done, the melted solder on the surface will be very thin and totally bonded to the steel on a molecular level of bonding. The bond is usually stronger than the tensile strength of the solder.

Let us know how it turns out after following my suggestions. :thumbsup:

 

[LaBonte]

Another mistake often made is to overheat the part or the surface

On the other hand under heating can cause problems - the "melt" temperature is generally lower than the flow temp (usually about 25-40°F higher than the melt temp) and it's the flow temp that counts along with the rest of Zonie's advise.
The right flux is just part of the "secret".
If you're unfamiliar with soldering practice on some scrap of a similar nature......

 

[LRB]

You can make decent flux from Muriatic acid, "pool acid", and water. Works very well. Mix 50/50, to a little stronger. I worked part time for a radiator repair shop for a short time, and thats all that was used. Be aware, it will quickly remove bluing and Plum Brown, and some other finishes.

 

[paulvallandigham]

Jim: Thank you for taking the time to instruct in detail how to properly solder items. I learned this all from my father as a kid, watching him solder electric wires to machines he was building in our basement. Later, I watched him tin metals other than copper wires, and use a different flux. I know what it is when I see it in the hardware store, but I could not tell you a brand name to save my soul!

I have misplaced my jar, after a couple of moves. I am always hoping to find it, as it should have lasted me all the rest of my life, with the small amount of soldering I do! Murphy's law says I will find my missing jar of flux the day I relent and buy a new jar to replace it! :blah: :shocked2:

I hope readers who have never tried to tin or solder anything pay attention, in detail, to the process you describe. In my HS shop classes, I had fellow students burning up the flux with direct flames, or applying the flame directly to the solder, and wondering why they could not get the solder to flow or stick!

I showed one student how my father tinned a metal part applying the solder with a brush-like "stroke" over the hot surface. He was amazed at how " easy " I made the process seem to work.

All our flat metal soldering was done after the parts were sanded down to clean them. That is another step people forget to do. My father was so fussy about this, that he even sanded copper wire that he had cut insulation off, just to make sure that the copper wires had no oils or oxides on them before he soldered a connection. That is the first time I saw Emery paper in use. I was probably 4 or 5 years old. Dad did use that resin core flux solder for the copper and zinc wire connections. He had a stick and a small brush he dipped into his jar of flux to use on soldering steel, which cleaned after use, and kept in a small soup can he had on his work bench.

With electrical work, he had NO choice but to touch the solder directly with his soldering ROD. When he passed on in 1996, those big heavy rods were still there, with thin layers of solder on their tips. :thumbsup:

 

[ol vern]

Thanks for all the info guys.

I learned to siliver solder when I
was doing refergion work but for some reason just could not
get the hang of lead soldering. I think at least part of my problem is my torch is not adjustable and I am overheating the work

I am going to run down another torch that has a controlable flame and see if that cures my problem.

 

[MSW]

oldvern, that will do the trick.

good luck with your project!

 

[squirrellluck]

Just back your torch away from your work a little. Just like you did when silver soldering refrig. lines to prevent blowing holes in the copper. Works just the same for controlling heat with lead solder :wink: