Hi Karen I got some experience in casting insects. It was a hobby of
mine. My workshop used to be in a hotel and the management was very
liberal with poison, much against my will. This resulted in many
insects being killed, thus many castings. I only used spin casting
and I only was successful about 80% of the time.
When your Orb spider has finished her egg sac, you might as well
catch her and kill her.
Reason ? As she dies she will crawl off somewhere and you won't find
her, or she'll drop to the ground and the ants will damage her.
Besides, they start shriveling up soon after they done the egg
thing. The best way to kill any insect is to put it in a bottle and
This also allows you to choose the time of casting. Also, only cast
insects in absolutely perfect condition.
I sprued up as follows:
On the thorax of the insect, at the bottom, I put the main sprue,
about 6-10mm thick. I make it as thick as possible, even as thick as
the width of the abdomen. An Orb spider has very thin legs. This is
a problem. You have to sprue each leg just above the foot, sometimes
on the shin and also on the thigh.( sorry, I don't know the correct
names) With an Orb I would probably use 4 sprues on each leg 1.2mm
thick, only on the smooth parts. Also you have to thicken all the
joints with a bit of wax applied with a hot needle. If you don't
there will be porosity there, and they will break off after casting.
Normally sprues will be about 1-2mm thick.
From the main sprue a 2.5mm sprue will go to under the pedipalps.
Always sprue underneath the insect. Thicken the joint with wax
between the head, thorax and abdomen if necessary A 3mm sprue will go
to under the middle of the abdomen from the main sprue. Your Orb
will have 35 sprues when you finished..
A spider abdomen becomes soft after thawing and deforms under its
own weight as it rests on the sprue.I think an Orb won't ( I have
never cast one) but I think they have a harder skin than the soft
furry abdomen of say a Sun spider. Low temperature wax applied with
a very hot needle permeates into the skin without loosing too much
detail and solves the problem somewhat.
I have learnt that over sprueing is always the best. It makes
finishing of a real mission but it is better than having a miscast. I
always cast in silver and I make up a fresh alloy at 95% fine with
5% deox .I don't use copper although I have been successful with a
97% solution. Fine silver does not work for me.
I use higher purity alloys because when the insect is sprued up it
is not in a natural position and therefore it makes bending it back
easier after casting.
I use Satincast 20. First I mix up some plaster and paint it on the
insect. Then as it starts to gloss over I mix more and paint on
more. I do this at least three times. If you let it harden too much
between the layers they separate and you get major flashing. As the
last layer glosses over I put the flask over and pour it full.
Obviously vacuuming is not an option.
I would use a 4 inch flask for that size spider and I would carve
the button cavity about a third larger, so you can put a LOT of
metal in. No less than 100- 150 grams.
I burn out for 8 hours at least. Centipedes, as they burn out, for a
long time smell like baking biscuits (no kidding) Most insects smell
like Satan's own cesspool.. Be warned=85 I use a normal cycle, then I
keep the temperature at 700 to 750 Celsius for at least two hours
sometimes more. I cast at 650-700 Celsius. I don't get sulphur
I wind my (cheepo) spin casting machine two and a half times
normally, but for insects I add one more turn. As soon as the button
is not red in neon light I quench. I had never had temperature tear
yet=85 Cleaning up is a real hassle. I use diamond and tungsten carbid=
burrs and steel brushes.
I clean the oxide off with sulphuric acid, by heating the insect up
and then quenching it in cold acid. Man, I hate doing that! But it
works well. Sometimes a bit of chitin is stuck on top of the insect
but it usually blends in with the texture of the body.
I have found, trying to burn the Chitin (sp?) out of an insect is a
waste of time (for me). I just blast it away with the highest temp
and max power I can get away with.
Then Liver of Sulphur and a light pass with a steel brush. I have
often wondered if electro polishing would not be a better option, on
account of all the fine little hairs get broken off with a steel
brush., Maybe someone could tell=85
I have never been successful with winged insects, even if I thicken
up the wings with wax.
I have successfully cast the legs and claws of a road kill Pels
Fishing Owl. I know the bone did not burn out completely, being
calcium, so I assume that the silver encased it. I have never been
successful at casting sea shell or coral. I vulcanize it and cast
Go look at my website, under Objets'd'Art for pictures of some of
the insects. They not the best but they will give you an idea. A bit
macabre, I know, but all insects shown were either dead or dying.
Cheers, Hans Meevis