# Silver (hard) solder flux



## 12bolts (Nov 12, 2014)

When my silver solder paste starts to get a bit dry I usually add a few drops of tap water to moisten it up again. Am I doing the wrong thing?

Cheers Phil


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## Ulma Doctor (Nov 12, 2014)

Hi Phil,
i don't know what type of flux you are using down under.

I use a boric acid (hydrogen borate)[borax derived] / denatured alcohol mixture.
you add just enough denatured alcohol to dampen the mixture to make the paste.

i'm not sure what water does in combination with your flux


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## Kevinb71 (Nov 13, 2014)

My Dad did refrigeration work(along with a bunch of other stuff) and would always add a bit of water to his "Harris Stay Silv" flux bottle and then stir it around some. I think he had the same bottle for 15 yrs or so. You might want to use distilled water just to make sure that nothing gets added to the mix that might react with the metals. It worked well for him!


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## John Hasler (Nov 13, 2014)

Ulma Doctor said:


> Hi Phil,
> i don't know what type of flux you are using down under.
> 
> I use a boric acid (hydrogen borate)[borax derived] / denatured alcohol mixture.
> ...



If it's boric acid flux water will work fine.  I've got some that says on the package to soften it with water.


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## Cobra (Nov 13, 2014)

Used the same bottle of borax flux for silver soldering for years. You can use either alcohol or water. The water stays soft longer, the alcohol evaporates better on the work.


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## 12bolts (Nov 13, 2014)

Thanks everybody. Im not sure of the type, (the label has peeled off.............) but its a white paste! Sounds like water should be ok

Cheers Phil


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## Mark_f (Nov 13, 2014)

I have a jar of that white silver solder paste and have been renewing it with water for over thirty years. Every great once in a while when I need it , it is all dried up. A little water and like new again. jar looks to hold about a cup. it is about half gone. Going to outlast me that is for sure.

Mark


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## oldgoaly (Nov 16, 2014)

Yes water works, been doing it for 25+ years


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## Ozwelder (Nov 16, 2014)

12bolts said:


> When my silver solder paste starts to get a bit dry I usually add a few drops of tap water to moisten it up again. Am I doing the wrong thing?
> 
> Cheers Phil



Hi Phil

I have been adding water to mine for years and not noticed any bad effects. I use just enough to achieve original consistency. About that of a heavy cream.


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