[TheForge] Re: Forge welding

[Mike Spencer]

Roger Degner wrote:

> I use anhydrous boarax which comes from a chemical supply house not
> 20 mule team that was boiled and then ground which still has water
> in it or absorbs water.

Laundry borax -- the 20 Mule Team stuff -- contains 10 (!) molecules
of water for each molecule of borax (sodium tetraborate) as "water of
hydration".  That is, it's not wet or even slightly damp in the usual
sense.  The configuration of the borax molecule is such that those
molecules of water bind to it very tightly even when the borax seems
to be powdery dry.  Toasty-warm won't drive off that water but the
temp of orange- or yellow-hot iron will.

When you put such hydrated borax on a piece of hot iron, it writhes,
froths and foams as those 10 molecules of water are driven off.  Maybe
that doesn't matter if you're welding anchors or axles but for
smallish or very delicate work, lots of the borax just falls off (into
the fire if you apply it with a spoon in the fire) and fails to melt.

I put a bunch of 20 Mule Team borax in a long-handled iron ladle and
melt it in the forge.  As the water is driven off, I add more borax
until the ladle is half full or so. Then I pour the melt out onto a
steel slab where it hardens into a brittle, greenish-black, glass
puddle.  Break it up a bit with a hammer and run it through an old
food grinder to get a gritty powder of -- ta-DAH! -- anhydrous borax.

That powder sticks to hot iron real good, melts quickly at orange heat
and wicks into joints pretty well.  Doesn't foam and froth.  And
it doesn't seem to pick up water from the air, either, so it keeps
indefinitely. 


FWIW,
- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^