[TheForge] Re: Flux, was rust & pickling

Tue Aug 19 15:19:01 2003

Has anyone tried to dehydrate borax in a micro wave oven?
Chuck
----- Original Message ----- 
From: "Bruce Freeman" <[email protected]>
To: <[email protected]>
Sent: Tuesday, August 19, 2003 1:44 PM
Subject: [TheForge] Re: Flux, was rust & pickling


> This subject seems to come up repeatedly.  I don't know specifically
> about borax, but most inorganic chemicals start releasing their water at
> temperatures much below their melting points.  Working at about 350 in a
> standard oven would probably suffice.  Again, I haven't tried this with
> borax, but I'd suggest trying it before going to higher temperatures or
> melting and regrinding it.
> 
> Many anhydrous chemicals, probably including borax, will absorb water
> from the air.  However, the simple expedient of keeping it in a closed
> container will protect it from air.  The short time it is open for use
> will generally not result in a massive uptake of water.  I'd suggest you
> keep your anhydrous borax in a large jar, and pour it into a smaller
> jars for use.
> 
> Bruce
> NJ
> 
> >>> [email protected] 08/19/03 12:45PM >>>
> 
> > So are you telling me that melting borax on an iron cookie will pick
> > up some of the iron?
> 
> Following up to my own post...
> 
> How do you melt borax on a cookie tin?  The melting point is around
> 1500F, a red heat.
> 
> Checking in the handbook, borax loses 8 of its 10 bound water
> molecules at 140F and the rest at about 400F.  But it doesn't melt
> until waayyy hotter than that.
> 
> I never tried to dehydrate borax in the oven at, say, 450F.  I melted
> some up last night over the forge in a cast iron ladle (kinda messy),
> poured it into a cast iron bowl where it turned to black glass.  Broke
> it up into pea size, then ran it through an old manual meat grinder
> with the hamburger die modified to be more like a grain grinder.  Nice
> powdery stuff that should be good for flux.
> 
> Someone said that anhydrous borax will quickly re-absorb water from
> the air.  I think a maybe the advantage to bothering with melting and
> grinding the borax is that in the glassy state it doesn't do that very
> readily.
> 
> Just 'spearminting around...
> 
> - Mike
> 
> -- 
> Michael Spencer                  Nova Scotia, Canada       .~. 
>                                  
>   /V\ 
> [email protected]            
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> http://home.tallships.ca/mspencer/ 
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> -- 
> 
> 
> 
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