Well, I 'm not going to talk bad about you or your project. I owned
and operated a small plastic injection molding business and what you
are doing sure doesn't look like injection molding. Looks like
squirting hot snot into a mold and letting it cool. What exactly is
the resin you are using?
The last job we did before shutting down due to a more pressing need
for the electric power was a cheese baiter made from several
polyethelene pieces. The stinky cheese bait was pressed into a holder
then pressed back out a little at a time to bait the hook. Supposedly
never got the stuff on your fingers. The old guy that invented it
passed away a few years ago. Lost my shirt on the job.
Could you not get the same results from RTV?
Its called plastisol in the bait making circles. I believe it's a heat
activated PVC with an oil based suspension to control the hardness when it
cools. It comes as a white liquid, and if it sets for a while it separates
out with what looks like a light oil on top. After it has been heated past
its activation point it resets or cools as the rubbery pseudo solid you see
in the video. RTV silicone is to my knowledge not used for this type of end
product, but there are some bait makers that use RTV carefully mixed with a
tiny bit of water to make it cure to make molds for hard baits. One shade
tree approach is to use store bought silicone adhesives. Basically hard
mold for soft bait and soft mold for hard bait. There are also a few who
use RTV molds for soft baits but from the videos I have seen it looks like
they are kind of a pain to de-mold.
I assume you mean silicone with RTV chemicals added. I don't actually know
much about using RTV silicone, but the curing time is measured in hours or
days with the few I have worked with. Also most of the RTV silicones set up
way to hard and with not enough stretch for this type of bait. The break in
the video I posted was only a minute or two. By the time I shot the fourth
mold I could have started de-molding the first one, but I wanted to let it
cool a few extra seconds so hopefully I wouldn't drop them or bounce them
around in my hands like a hot potato in the video. LOL. With six or more
molds I could shoot basically nonstop. When I do a larger batch of plastic
I use a Presto Pot instead of the Pyrex cup and the microwave, and I set all
my dross aside in a baking pan to re-melt later.
While laying awake for several hours last nite, the syringe you were
using to suck up the plastic goo kept appearing. Then I realized what
it was. Dad used an identical device to shoot medicine into the back
of animals mouths so they would have to swallow it. Yours looks rather
short, like for animals smaller than cattle. Am I correct?
Well it might be considered shooting medicine into cattle... Medicine to
make dead cattle taste better. The one I was using in the video shoots
marinade into meat. It was originally setup with a needle about four inches
long with several holes along its length. I cut off the needle and drilled
out the remains of the tip so that the plastic would flow more easily.
On Tue, 22 Jun 2010 14:41:07 -0400, Spehro Pefhany
OMG, I just remembered that I had a Mattel Vac-U-Form as a kid! I
hadn't thought about that for 45 years or so.
Peace of mind is that mental condition in which you have accepted the worst.
-- Lin Yutang
CNC mini mill.
Mill - Taig 2019CR
Controller - Deepgroove1
NC - Mach 3
CAM - Cam Bam 0.9.7
CAD - Cam Bam, Inkscape, Corel Draw, Gsimple
Now that I am learning how to use it Cam Bam is really becoming a great
tool. A couple of the molds I made were designed with the simple CAD tools
built into Cam Bam. Makes me wish I could afford a real machine with super
high speed spindle and automatic tool changer. The next thing I need to do
is stop playing with my machine for a while and learn how to use a serious
CAD program. After I finish putting my lathe back together...
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