Cleaning glass with acids causes corrosion of the surface of the glass.
So many people mention using vinegar to help clean the ground
edges. I can't resist commenting. Vinegar is acidic. Glass is alkaline. Leave
the glass in the vinegar too long and it will affect the surface of the glass.
Sometimes it dulls. Sometimes it corrodes to give a mild
iridised appearance. The acid removes the alkaline materials – potash, lime,
etc. – leaving a pitted surface at the microscopic level. Left long enough – hours rather than days –
the surface will begin to appear dull due to the pittiing. It is at this stage
that it is easy to introduce contaminants which may later form nucleation sites
for devitrification.
If you must use vinegar, rinse with it. Do not soak your
glass in a vinegar solution.
Alkaline cleaners
Two alkaline substances that are used to clean glass are
baking soda and ammonia. Both are
effective cleaners and do not have a reaction with the glass as they both are
alkaline. The glass can be left to soak for a brief time in a solution of these
chemicals, although I would not be happy with an open bath of ammonia.
But the effective part of what people are doing to clean the
edges is the scrubbing. Scrubbing the glass powder out of the pits left by the
grinder is what really works. When
leaving the glass in a bath of even plain water, you are giving the powdered
glass the opportunity to settle into these pits. Once settled into the pits, the powdered
glass can become like cement to remove.
There is a much better cleaner, especially for removing kiln wash and investment mould material. It is a neutralised acid - tri-sodium citrate. It is often sold in the dihydrate form. It is used in the food industry and so is widely available. Glass can be left in the 6% solution for days without being etched. The unwanted material is chelated from the surface during this soak. Occasional agitation may speed the effect by removing the loose material on top.
Mechanical cleaning
You could have a much better effect if you scrubbed under
clean water before placing in a bath of water with grinder lubricant. This material promotes a gel like glass
residue. This gel prevents the glass becoming caked like cement.
A final scrub to thoroughly clean before assembly is a good
idea. Each piece should be polished dry with lint free cloths or uncoloured
absorbent paper. If any particles cloth
or paper are left behind, they will burn away long before devitrification can
begin to form.
Of course, the best solution is to grind with 400 or 600
grit. This is fine enough that there is
not enough powder left to promote devitrification.
No comments:
Post a Comment