[TheForge] Drying Borax (was: Welding flux?)

[Jerry Frost]

Give it a try Bruce and you won't tell us again. I'd love to give you a 
bit about the 1100f typo but you have Andy for that. <grin>

I worked in a soils lab for a while where drying samples is a science. 
Not the same science but it has to be done right. Hygrocopic moisture 
can be driven off at 230f. however at around 200f borax is fused into a 
block, it isn't the glassy slag of melted borax but it's mortar and 
pestel and elbow grease time. Drying in a gas oven means a minimum 230f 
and it turns into a white rock at 230f. I've tried an electric toaster 
oven for a prolonged time, 200f wasn't enough, 212f is pretty much the 
minimum to drive off moisture and 2 hours did it but meant hard 
grinding. I only tried a mortar and pestel for a really short time 
before getting the yard sale blender and even then it was time 
consuming, loud and beat hell out of that poor old blender. Were I to do 
it again I'd use the yard sale rock tumbler and steel bearings.

After a couple experiments trying to dry and grind borax I started just 
melting it in the forge and using it molten. It's so much easier.

Thinking about the plastic bottle I could just put a couple inches of 
1/4" copper tubing on the end and not worry about melting it.

Jer


On 7/22/2013 5:06 AM, Bruce . wrote:
> I've told you guys this already, now LISTEN UP!
>
> Chemists dry chemicals at relatively low temperature.  I can't give
> you an exact minimum temperature for drying borax, but I would bet
> money it's WELL under the melting temperature of the stuff (something
> like 1100 F!).
>
> Put the borax in a thin layer in an appropriate container into an oven
> and bake it for maybe an hour at something under 1100 F.  8^)   I
> would start with 250 F, but possibly a higher temperature would be
> needed.  A chemist would dry to constant weight, but a blacksmith need
> only dry till the stuff doesn't foam when placed on red-hot steel.
>
> Store the dry borax in a tight-fitting jar or can, as it will
> certainly pick up moisture from the air if you don't.
>
> No, I haven't tried to dry borax, as I've never see the need.  I just
> get the steel hot enough to melt the borax.
>
> The advantage of drying this way is that it avoids the grinding operation.
>
> BTW, I've got a friend who puts borax into old plastic grated-cheese
> containers for dispensing.  Same problem with those as with squeeze
> bottles.  But maybe somebody could fabricate a simple metal squeeze
> container -- think of the old oil cans with the bottoms that "oil can"
> (that's a verb, boy, that's a verb).  Or maybe get a very large old
> oil can, clean out the oil residue, and shorten and widen the spout to
> maybe 1" long and 1/4" in dia.  Alternatively, get a one-quart metal
> solvent can and drill a hole in the cap.  Fill it maybe half full of
> flux powder and use it as a dispenser -- the broad sides will "oil
> can" to help dispense the borax.