Is there a soft wax which I can use to take impressions? I have some
deeply etched copper which I use for rolling printing, and it works
just fine.
However, I have a nice stash of scrap silver waiting to be cast.
WhatI have in mind is using some soft wax and impressing it into the
deeply etched copper, and then casting the wax.
Is this possible? Usually I carve my designs into carving wax, which
is a bit time consuming. Hence it occurred to me that if I had some
soft, malleable wax, I could press it into the designs in my etched
pieces. This would not only save me time, but would give me a chance
to use my ever growing heap of scrap silver.
I will appreciate any suggestions. Thank you. Alma
Dear Alma, You might consider our Castaldo QuickSil RTV silicone
molding putty, which is often used for making impression molds. Once
you have the impression mold you can copy it 100’s of times in any
wax for casting.
Is there a soft wax which I can use to take impressions?
Alma, the very soft waxes, like sculpture wax or the red boxing
waxes are fine to push into a surface like that, but then difficult
to remove.
A method that works well, though, is to use slightly harder, but
still flexible sheet wax, such as the pink or green sheets, or the
harder salmon colors if you warm it up a bit so it’s flexible. Then,
and here’s the cool trick, put a layer of saran wrap or similar
plastic wrap between the wax and the pattern. Sandwich that with a
rigid hard surface like a sheet of thicker metal, behind the wax
(another sheet of plastic wrap between that back plate and the wax
is a good idea too. Also put something rigid behind your pattern if
it needs it. The squeeze the whole sandwich, pushing the wax into the
pattern. A vise works well enough, or a hydraulic press works even
better if you have one. Doesn’t need all that much pressure, but the
presses are good for keeping things flat. What the plastic wrap does
is act as a seperator, so you can peel the wax sheet layer from the
pattern, and then peel the saran wrap from the wax. No sticking, or
at least, much less than if you pushed the wax directly into the
metal.
I remember using this method to take impressions of linotype plates
(commercial zinc or magnesium etched printing plates) The results
would be wax sheets with very precise “stamped” images of the letters
in the wax. Because the “precision” surfaces of the plates are the
high flat printing surfaces of the zinc plates, when cast, the
bottoms of the “stamped” letters are crisp and clean, and don’t get
messed up when you clean up the castings, as the somewhat distorted
upper surfaces of the “stamped” images aren’t what you look at (this
is the same idea as what you see with physically stamped letters
using hammer driven stamps directly on metal). This method was a
great way to make cast plates with crisp lettering on them, such as
for medallions or other needs. Now, generally done by cad cam direct
carving of the wax, which is simpler. But the older method still
works as well as ever.
The soft waxes I can think of might stick and may be hard to remove.
What if you melted a harder wax and poured it on and it might pop
right off after it cools or you could put it in a fridge and see if
that seperates it. SD Red sprue wax might be soft enough when warm to
press into it.
Using silicon spray as a release agent for soft wax impressions
works very well. I have made many leaf impressions this way with
pink sheet wax in a screw press.
I use the the pink sheet wax and various combinations of waxes with
the saran wrap (clingfilm in the UK) and and find a few minutes in
the freezer and the wrap can be peeled off easily and cleanly.
Almost any wax works, trick is not to over press.
I back the wax with a silicone sheet to give a little push into the
etched plate which is then sandwiched between two metal sheets
between the vise jaws.
Ti-Research has a highly sophisticated photopolymer called NoWax ( NoWax Light Curing Patterns of Ti-Research for Free Form Design) which might work well for the
applications discussed here. Although it is not the cheapest
approach it might be worth the effort for some special challenges.
The material is soft before it is light cured and will harden like
plastic after curing. The sheet material in particular seems to be a
perfect match to capture structures.