RE: [hobbicast] RTV mold Process, Nice work Ray! + making living molds
- First of all, I second all the posts which congratulates Ray's work on his
new RTV mold process page. It's the most comprehensive guide I've ever seen
on the Internet!
About making living molds:
If you want to mold a hand (maybe your own hand) this is a very
a) Get a PVC pipe wider than your hand (maybe a 8 inch one, the ones that
Home Depot sells for sewage).
b) Get a piece of cardboard and seal one of the ends of the PVC pipe with
clay, plasticine of anything like that.
c) Go to a dental supply store and buy Alginate. Is the thing dentists use
to take a dental impression of your teeth. One pound costs something like $
6. Alginate has three important properties: a) it sets in seconds. b) It
sticks to almost anything. c) It's safe for your skin.
d) Mix the whole pound with COLD water (warm water speeds the setting
process A LOT), until you get a creamy consistency.
e) Put the pipe in upright position, pour the alginate inside and dip your
hand in the stuff.
f) Allow just a couple of minutes to set. Start moving your fingers a
little, a lift your hand with great care. You'll fill it like a latex
g) Once you are out, wait no time to pour a very water thinned plaster
slurry inside the "glove". Try to rotate the thing so you make sure the
thinned plaster is filling every single spot. Keep on adding plaster, until
you completely fill it.
h) Allow to set overnight.
i) Cut the PVC pipe and with great care start "peeling" the alginate. There
you've got the plaster hand! The process is so accurate that you should see
even your fingerprints!
j) Now you can coat it with RTV or whatever you want... the plaster hand can
wait still and with no complain for hours! :)
1) Alginate deforms as it dries. So once you demold it from your body,
you'll have to pour the plaster INMEDIATELY.
2) Instead of plaster you can pour wax! So you'll get a wax copy of your
hand, ready to do the lost wax process!
And finally, if someone is wondering about... yes, this alginate process
also is perfectly suitable for doing copies of intimate parts of the body.
Email me if you want some more details on this topic.
Hope this helps
> -----Mensaje original-----
> De: Ray Brandes [SMTP:rvb@...]
> Enviado el: Lunes, 01 de Octubre del 2001 07:54
> Para: email@example.com
> Asunto: Re: [hobbicast] RTV mold Process, Nice work Ray!
> RTV is available all over the place. Just search on RTV or click my link
> to Silicones, Inc. near the
> top of the page. I think Swest has it also. For casting a hand, check with
> Marcelo for his technique
> on making living molds. You will need something that sets a lot faster
> than RTV for a hand (unless it
> is from a cadaver!).
> Another technique is to use clear silicone and cast the entire part in one
> pour. When the rubber is
> set you cut the halves apart, almost to the end, with a razor. The
> irregular slashes of the razor
> make keys to keep the alignment and where they remain joined at the end
> acts like a hinge and keeps
> them from getting separated.
> Regards, Ray
> katou@... wrote:
> > Very nicely done Ray, good pix and all. A mark of a good Internet
> > process document is that you could (if you had to) follow the idea
> > just from the pictures, and you did that very well.
> > I only have one question, what sort of place sells the RTV
> > silicone stuff? I would guess Jewellery supply. How would you make
> > a mold of your hand for instance? I was thinking that it would
> > require a fast setting flexible rubber/plastic material. Then you
> > could slit it along the edge or something and pull your hand out.
> > Any ideas?
> > Katou
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