Could you please explain why you recommend using de-ionized or
distilled water or water that have been sitting overnight. Thank you
. I Anthony Williams and work in a jewelry casting house.
thank you
Anthony Williams
Hi, I don’t cast much, but I did help lots of people in my class
with the investing because I LOVE getting my hands goopy (leftover
from childhood…I’ll never grow up). We were taught to leave a
bunch of simple tap water sitting around for at least 24 hours to
use for investing. This is because water that comes out of the tap
is “filled” with air. Even if you can’t see the bubbles, they’re
there. Trust me, the difference between a casting with fresh tap
water and old tap water is just phenomenal. I suppose we used tap
water at school to save money, but I’m sure that using distilled or
de-ionized water would be preferable (what with all the nasties
that one finds in tap water).
I hope I helped.
Tobey
Hi Water Wonderers, You don’t have to leave the tap water arround
for a day, you can simply vac the water first and go! As for any
advantage with distilled, you may bypass tap water additives like
clorine and florides, but it’s dubious as to their effect on the
investment. I have a strong vac unit and use straight tap with no
ill effects. Still, a buck for some distilled can put to rest at
least one variable in ones mind. J.A.
The reason that you should use distilled or deionized water is
that tap water will cause inconsistant results. In any process you
should endeavor to remove as many variables as possible. When you
leave the tap water out over night some of the air and chlorine is
removed but not any minerals. The chemicals in tap water are not
constant throughout the year, every thing may be fine now but in
two months there may be something in the water that causes the set
time of your investment to be extended by several minutes. When I
was in the Northwest I used tap water and never had any problems.
When I moved to the Midwest I found that the same batch of
investment mixed at the same temp at the same ratio was taking 3
more minutes to set up, with a slight increase in the roughness of
the castings. I went to distilled water - no more problems. Air in
the water is not a problem as I use a vacuum mixer, but if you
don’t have one the distilled water should have very little air in
it. Brett Split Image Jewelry Contracting
We were taught to leave a bunch of simple tap water sitting around for at least 24 hours to use for investing. This is because water that comes out of the tap is "filled" with air.
G’day - I can’t keep my nose out of things! Leaving water -
including distilled or de-ionised water “sitting around” won’t
remove the air which is dissolved in it. The only way remove
dissolved air is to boil the water and allow it to cool in a closed
vessel, then use it as soon as you can afterwards. If you have a
good vacuum pump you could use it to de-air water to a certain
extent at room temperature. All “sitting around” will do is to
give the chlorine put in by the water authority time to convert to
hydrochloric acid - though not very much of that will be present.
One uses ‘old’ water if one changes the water in an aquarium, to
allow time for the chlorine to convert, and for air to dissolve
in the water! Which the fish must have of course.
/\
/ / John Burgess,
/ /
/ //\ @John_Burgess2
/ / \ \
/ (___) \
(_________)
From the literature I’ve read and my own personal experience, it
is fairly well established that water used for investment ceramic
needs to be de-ionized since “normal” water contains up to 7% H+
and OH- ions. Since these ceramics usually contain silica, this
can cause a problem since the OH- ion loves silica. A distilled
or filtered water will remove other unwanted “tramp” compounds
into the ceramic. The notion of leaving the water sit inside
overnight prior to use allows a controlled temperature for your
water instead of being at the mercy of the weather in your area.
Making an investment ceramic is really chemistry in action and we
all need to control the pH (ions), the contaminents, as well as
the temperature of our ingredients. I obviously love this
subject, so if you want to discuss this further, just e-mail me. I
hope I have been some help here.
G’day - I can’t keep my nose out of things! Leaving water -
including distilled or de-ionised water “sitting around” won’t
remove the air which is dissolved in it. The only way remove
dissolved air is to boil the water and allow it to cool in a closed
vessel, then use it as soon as you can afterwards. If you have a
good vacuum pump you could use it to de-air water to a certain
extent at room temperature. All “sitting around” will do is to
give the chlorine put in by the water authority time to convert to
hydrochloric acid - though not very much of that will be present.
One uses ‘old’ water if one changes the water in an aquarium, to
allow time for the chlorine to convert, and for air to dissolve
in the water! Which the fish must have of course.
This all seems logical: why don’t the fish die? But I can
guarantee that leaving water lying about DOES reduce bubbles in the
investment significantly, so much so that I keep a 25l tank of
water in the workshop for this very purpose. Any scientists like to
comment?
Dauvit Alexander,
Glasgow, Scotland.