Casting Poinsettias - Very Odd Results

Folks,

I’ve done quite a bit of casting of organic materials into silver
and just ran across a VERY odd occurrence. I’m wondering if why of
you have experienced it and maybe have some thoughts on it.

I have a gorgeous “fancy” poinsettia with the ruffled leaves. I
clipped a bunch of the leaves (these are large leaves, about 3 - 4
inches in length and at least 2 inches wide. The leaves themselves
are fairly thick and have very pronounced texturing and large veins.
As I normally do, I backed the leaves in a pretty thick layer of wax,
applied by paintbrush. I let them sit for a week before investing
(they looked fabulous at that point).

I invested the poinsettia flask and another flask of organics (no
poinsettias in it) out of the same batch of investment,
simultaneously pouring, vacuuming, etc.

After casting, I quenched the poinsettia flask fairly quickly (about
a minute after casting, when the redness was gone from the button).
The button was an appropriate size, by the way. Shockingly, to me,
the plaster in that flask was as hard as a rock, somewhat black on
the outside and shiny where it had been in contact with the flask. I
know this because it took me 1/2 hour of digging away at it to
finally dislodge enough of it from the flask to get it out to work on
it. Every last bit of that plaster had to be “sculpted” off the
silver and it was harder than I’ve ever felt a plaster get. The
odd(er) part is that not one of the leaves filled completely – all
have holes in them (center and/or edges) that made them unusable.

The other flask was completely normal.

This leads me to conclude * There is something odd about poinsettias
that reacted with the plaster to cause this reaction.

So my questions:

  1. Has anyone else tried this and had a similar occurrence?

  2. Is there anything I can spray or seal the poinsettias with to
    prevent it?

  3. Would a double burn-out help? (this was a 6-hour burn with a
    1350F max)

Any and all suggestions welcome!

Thanks,
Karen Goeller
@Karen_Goeller
www.nolimitations.com

Has anyone else tried this and had a similar occurrence? 
Is there anything I can spray or seal the poinsettias with to
prevent it? 

Hi Karen, haven’t tried casting poinsettias, just a suggestion for
you - make an impression of the leaves with something like the
castaldo 2 part moulding compound, then pour wax into this. No
burnout problems, etc. It is interesting about the poinsettias
though, isn’t it?,

Christine in Sth Aust

Hello Karen,

From what I remember about poinsettias from landscaping, they have a
milky oil they use to protect/heal themselves. This is the substance
that makes hands sticky and itchy when poinsettias are handled. It
is possible that the plaster and water reacted with the oil. Maybe
there’s a local nursery that could point you towards different
varieties of plants - I want to remember that someone was trying to
alter this characteristic.

I don’t know if a spray would help - every time our poinsettias got
wet or leaf shine on them, they turned black and fell apart.

Good luck,
Susannah

I think the main problem with your casting was incomplete burnout.

Last month I casted a lot many leaves as thin as 0.3mm successfully
in 18 karat gold. My burnout cycle was,1 Hr at 100 degree centigrade,
second step 1 Hr at 200 degree centigrade, third step 1 hr at 300
degree centigrade, last step 720 degree centigrade over night and in
the morning, lowered the temp to 600 degree centigrade, hold it for
one hour at 600,then casted. I am doing centrifugal casting in a
motorised casting machine ( i constructed in 1989), i have used the
double jointed casting arm from a dental casting machine from
Germany. I keep start speed at 125 rpm then increase the speed to 350
rpm in next 4 seconds. I have never had any problem with my castings
since last 15 years now, the reason I think is that i have installed
an small extractor fan behind my burnout furnace ( i have designed my
burnout furnace in 1989, the hole at the back of the furnace where
the extractor fan is installed) which helps to drive away the carbon
monoxide gas and brings fresh air from the front door hole of my
burn-out furnace, so there is enough air circulation needed for a
perfect carbon free burnout.

I always normally cast in the morning, so whole night the automatic
temperature controller keeps the temperature at 720 degree
centigrade, and the burn out is complete with no carbon left in the
flasks,each flask is totally white, and the centrifugal force gives
very dense castings as one can see from the button, which is flat and
some what concave, not like the vacuum assist casting machine where
there is only the gravitational pull and vacuum where the button is
convex, since there is very little pressure on top of the button.

Hope this will help.

May God bless us all with Total Health, Mental, Physical, Spiritual
and Social.

Strive to be happy
Umesh

Poinsettias have a heavy sap in them that has some rather nasty
things in it and is very corrosive. I wonder if this has anything to
do with the problem?

Margaret

Hi Karen,

There is something odd about poinsettias that reacted with the
plaster 

I worked with pointsettias in a green house for a number of years,
including propagation from cuttings. They have a very thick, viscous
white juice that runs out of the stems when cut that gloms onto
everything. I think it’s related to rubber, and is very sticky and
hard to remove from fingers, etc. Some people had an adverse reaction
to the juice and had to wear gloves while handling the plants and
cuttings. Perhaps this is related to the reaction of the investment
and burnout. (Sorry, I don’t cast, so no help on that side.)

Melissa Veres
@M_Veres

Hi,

I don’t cast myself, but have you thought about painting the
poinsettias with metal clay slip, then when you have the relative
thickness you want, you could fire the ponsetta petal and you would
be left with a silver poinsettia petal that you could cast. My
designs are very organic and I always do this with leaves, petals and
twigs and then send them to be cast in silver or gold. It’s an idea

Barbara