# what's acid core solder good for?



## SE18 (Feb 21, 2008)

I'm not using it for electrical stuff but have some brass and copper and nickel silver parts I want to solder together for structures and track parts outside (switch stand rods and such). I always hear not to use it from model railroaders but I'm assuming that is only for wiring and electrical connections.


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## Torby (Jan 2, 2008)

I used to use it for ferrous things like piano wire or spring steel. Keep it away from brass, copper and nickel silver (which is actually brass).


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## SE18 (Feb 21, 2008)

thanks. what problems would one experience? Does it rust. Does it somehow have a bad reaction and separate?

Stuff's cheap (pricewise)


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## Don Gage (Jan 4, 2008)

SE18, 
The acid flux is extremely corrosive an can cause all sorts of issues if it is not completely removed from the surfaces and joints, electrolysis being the main one causing dissimilar alloys to devour one another over time. I use rosin core solder for almost all things I solder together. The only requirement is that the surfaces are clean and free from oils. While the rosin core solders are a little more expensive they are available in multiple diameters. Some stores call it Radio Solder, same stuff. Hope this helps, Don.


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## Larry Green (Jan 2, 2008)

Acid-core solder and liquid acid fluxes are primarily for certain industrial situations. For our type of work, stick with rosin flux. I prefer the paste flux, with solid solder which can be flattened and cut into narrow strips for fine work. You can get the same cleaning advantage that acid gives by rubbing the areas to be joined with a Scotchbrite pad or medium aluminum oxide paper, right before soldering, and being careful not to burn (overheat) the area if using a torch. 

Larry


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## SE18 (Feb 21, 2008)

thanks all; I'm assuming overheating/burning puts a layer of carbon or film that impeds the solder. I'm guilty of overheating.


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## Bill Swindell (Jan 2, 2008)

Overheating usually happens when you try to solder with a torch. Do not ever use acid core solder on electrical wiring. The acid, if not completely removed, will dissolve the copper wire. 

I have used acid core solder with a large iron when soldering nickel silver switch parts in HO. The switches are still there after 30 years so it must not be too bad. Cleanup is still a must. Acid is also used for soldering copper plumbing. 


Other than those uses, I suggest rosin core and an appropriate sized soldering iron will do the job. I do not use a soldering iron for anything. I find that the often are too slow to warm up and then get too hot to use easily.


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## Skip (Jan 2, 2008)

Acid core flux contains gelled muriatic acid. Its used for soldering galvanized sheet metal, like galvanized eavestroughs and ducting. The acid's job is to etch the zinc surface of the galvanized metal so that the solder can flow into the etched pits on the surface and allow the solder to hold. After soldering, you clean it up with a good scrub of soapy water if you want the metal to last.


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