There is so much to say and I do not have the time right now.
Do not use Hydrochloric acid for investment removal. It is too
strand an acid. We do not use any a cit for investment removal, we
use ultra sound unit and if that is not available an old toothbrush
and running water. It helps to put the can/setup into water while
still somewhat hot, BUT not too hot (wait for to or 15 minuted after
casting then put the whole can in water. The temperature difference
of the hot can/investment/metal and the cold water causes lot of
breakdown of the investment, the more temperature difference of the
can and the water, the more breakdown of the investment.
What metal are you pouring? 700 deg. is that F or C? If F I think it
is too cold, we pour mostly by “color” inside the cavity to be
filled, we shoot for a deep red and it is far hotter than 700 F. If
you are measuring C then you are close to the correct temp but if
you have fine areas to fill, the filigree, metal and flask
temperatures may both need to be on the hot side. Are you gravity,
vacuum, pressure or sling casting. Straight gravity is often not
enough to get filigree to fill, you need to “assist” the metal into
the smaller areas, thus vacuum, pressure or sling is needed.
Art the thin pieces supposed to be thin? If they are supposed to be
thin, use other cleaning methods that blasting or high pressure
water, , an old tooth brush, a very short cut bristle brush, etc.
to clean the investment. Final cleaning in an ultra sonic, if
This is not very inclusive of ideas/thoughts, but it may be of help.