Noitoen said:
Last week I had a chance to try a trick I read somewhere, to limit the flow of solder all over the part being soldered. I didn't think it would work, but it did. The trick is to use a soft carbon pencil, (I used a B type) to outline a border where we want the solder to stop flow. I was soldering a little pipe nipple (3mm) to a small plate, so I drew a circle around the nipple, and the solder didn't flow over this line. I was surprised
Its the graphite in the lead mix that stops the flow, another item that can be used is the Liquid paper typewriter correction fluid in the bottles the white or colored material will also stop the flow(be aware that the fumes from the solvents used are toxic use in a well ventilated area).
Powered rouge(iron oxide) or whiting powered calcium carbonate mixed to a paint like consistency water or alcohol can be applied to areas that excessive heating of solder flow is not wanted.
You can also use garlic juice as anti flux.
Yellow ocher paste is also used, along with India ink(the carbon in it)
The best pencil to use is a #1 graphite pencil. As some of the pencils coming in from the overseas producers don't have as much graphite as they should and other stuff is being substituted for it.
Two important things to remember when using any of the anti flux materials.
1;Don't let the anti flux materials from mixing with the flux as it will render the flux less effective.
2: All the anti flux material must be removed before pickling the work as they shorten the working life of the pickle.
To direct the solder to were you want it to go, a sharpened TIG Tungsten in a wooden dowels will work as the solder will not stick to the tungsten. And that what's in the fancy ones from the supply house.
As for the solders available at most jewelry supply houses:
Easy Flo 1145'F 618'C
Extra-easy 1205'F 652'C
Easy 1325'F 718'C
Medium 1360'F 737'C
Hard 1450'F 787'C
"IT"/enamel solder 1490'F 809'C
The IT/enamel solder is used for attaching pieces together that will be glass powdered enameled in a kiln.
The easy flo has cadmium in it, the extra easy uses tin instead of the cadmium.
The higher the temp for the flow point of the solder, the more silver in the alloy and the less copper and zinc.
Some names of store bought fluxes
Battern's, Allcra, Hillco Fluoride/Boric acid based liquid flux
Handy flux, Dan-Dix Borax-based paste
Cuupronil is great for repair work
Prips flux excellent firscale protection
;D