I recently read a blog post by the very talented Orchid member Steve
where he mixes a flux with a very unusual component, Cabosil. It has
been several decades since I worked with Cabosil in plastic casting
and I never would have thought to mix it into flux. If you are not
familiar with Cabosil it is fumed silica. It occupies a huge volume
but weighs virtually nothing it is used as a thickener in many
products ranging from plastics to food. It is virtually inert and
does not dissolve in anything short of HF or hot molten alkalis so
when added to liquids it keeps its volume makes them into gels.
Anyway Steve’s idea was to use it to make Magic Flux into a gel to
extend it and allow it to stick to large volume forms to prevent
firescale. I thought it made for a very interesting idea so I
ordered some Cabosil.
I tried mixing it with Rio’s Stop Ox II and isopropyl alcohol in
similar fashion to Steve’s use of Magic Flux. I mixed enough Cabosil
into it to make a stiff gel and applied it as a fire coat. I felt it
worked well as a fire coat not necessarily better than others but
the way it is applied makes it a lot less messy than spraying Stop Ox
onto heated metal
I tried it as a soldering flux and it was not very satisfactory but
that is not surprising as Stop Ox is not a good soldering flux. So I
tried mixing some Handy Flux with Stop Ox and then adding Cabosil
and Isopropyl alcohol agin to a some what stiff gel. I used a small
spatula to apply the flux gel almost like a caulking to the edge of
the joint. Then I pushed the solder pallions into the gel and then
heated the test piece. First off the pallions did not move while I
heated the work! I don’t know about you but keeping solder in place
while heating a wet flux is often maddening as often the steam of
the evaporating flux will launch the pallions all over the place.
These did not move it was rock solid. The addition of the Handy Flux
made the solder flow nicely across a long seam I had no voids and the
solder stayed right where it was placed while heating and very
little that flowed anywhere but into the joint. Another thing that
the gel did was allow me to place the items in it almost like a glue
they did not move at all so it acts a its own fixture if it is stiff
I think this idea has a lot of potential, I plan to continue to play
with this to try to refine the mix of components. If you like to
experiment then I would highly suggest you give this idea a try.
This the thing that makes Orchid so valuable. I never would have
thought of this and it is not the first time nor will it be the last
that I get my eyes opened by the creative minds here.
P.S. Cabosil is finely divided silica, wear a dust mask when
handling it in its dry state and mix it with good ventilation. Also
wipe down the work area where you mix it with a sponge to clean it
up. It is not a problem once mixed with a liquid but you do not want
to breathe it. The danger of silicosis is not to be taken lightly.
James Binnion Metal Arts