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Shake Yer Booty update Jan. 22 Materials: Where to get 'em! |
Bowana
Grand Member (4 years) 
Joined: Nov 10, 2006
Posts: 1129
From: La Mesa, CA
|  Posted: 2006-11-24 6:34 pm Permalink
Here are some shots I took of the casting process for this tiny figure.
This is the silicone mold just after opening. The front side has been removed from the piece. The casting is urethane resin. That weird looking stuff around her sides are vents cut into the mold to allow air to escape from the elbows and hands as the resin is being poured in. The resin fills in these cavities too and are trimmed off later.
This is the casting after the back of the mold was removed. The grass reeds in her right hand broke off as a result of an air bubble caught in that area. My vent failed me!
This is the mold showing the base of the figure (those holes are her feet). While this is the bottom of the figure, it is actually the top of the mold. The cavity pictured is where the resin is poured into. In this case, the piece is so small that I had to employ a syringe to inject the resin.
The cleaned up casting. The pom-pom (does anyone know the proper name for these things?) in her left hand broke off as well. I repaired them with some epoxy putty, and also patched up a few other flaws.
Now that I have a hard copy of the piece, I can do some further detailing by carving into it with an X-Acto knife or Dremel. Then comes the paint!
[ This Message was edited by: Tikidav 2006-12-16 14:22 ]
[ This Message was edited by: Tikidav 2006-12-21 21:07 ]
[ This Message was edited by: Tikidav 2007-01-01 19:19 ]
[ This Message was edited by: Tikidav 2007-01-13 10:50 ]
[ This Message was edited by: Tikidav 2007-01-22 21:11 ]
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hewey
Tiki Socialite
Joined: Sep 14, 2004
Posts: 4270
From: Sydney, Australia
| Posted: 2006-11-24 7:14 pm Permalink
kool, thanks for the step by steps
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Paipo
Tiki Socialite
Joined: Jun 22, 2006
Posts: 1886
From: Aotearoa / NZ
| Posted: 2006-11-24 7:27 pm Permalink
Very nice, I know all too well the perils of air bubbles. I haven't yet made a two piece mold though. Did you just pour one big block of rubber and hack it in two with a sharp blade? Will you make a new mold of the "refinished" hula girl?
I still find it hard to believe this thing is only 3 inches tall....
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Bowana
Grand Member (4 years)
Joined: Nov 10, 2006
Posts: 1129
From: La Mesa, CA
| Posted: 2006-11-25 08:56 am Permalink
Thanks, Hewey and Paipo.
The mold was made by cutting out the bottom of a Dixie Cup and sticking it down on the board around the figure, securing it with the use of a hot melt glue gun and plaster bandages. I always try to make the attachment to the board as bulletproof as possible. If the cup were to pop off after it's full of silicone, it makes a god awful mess.
The mold is cut open first around the edges 1/2"-3/4" deep with a curved key-knife. This knife makes a "c" shaped cut that will allow the two mold halves to match back together without sliding around. Next an X-Acto knife is used to cut around the model and free it from the silicone.
I find it helpful to draw a simple diagram of the figure with notes pointing out where vents and various features are before pouring the silicone. Once you start cutting, you are operating blind and it's easy to get lost.
I don't know yet if I'll make a second mold or not on this figure. She might be just fine as she is.
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4WDtiki
Tiki Socialite
Joined: Aug 03, 2004
Posts: 1741
From: Omao, Kauai
| Posted: 2006-11-25 1:42 pm Permalink
Tikidav, are these something that will be available to us? (pleaseohpleasepleaseplease):D
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Bowana
Grand Member (4 years)
Joined: Nov 10, 2006
Posts: 1129
From: La Mesa, CA
| Posted: 2006-11-25 5:44 pm Permalink
4WD: It's possible that they could be available. Glad ya like her so much. She's really difficult to cast though and at this point I've only managed to get one almost perfect casting.
They want to keep coming out like this  , which breaks my heart because that means that I must put them out of their misery.
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Tamapoutini
Tiki Socialite
Joined: Aug 30, 2006
Posts: 1529
From: Aotearoa (New Zealand)
| Posted: 2006-11-25 10:43 pm Permalink
Quote:
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'Vahine De Milo'? 
Great explanations on your process.
Awesome pics too!
Tama 
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Tipsy McStagger
Tiki Socialite
Joined: Nov 21, 2004
Posts: 3394
From: HELL
| Posted: 2006-11-26 10:39 am Permalink
..try using a mold release agent that you spray into the mold before casting....this will loosen her up faster than a couple mai tais....in the future, consider making the pom-poms a separate mold...this way you can use a pin to locate them in her hands and epoxy them after you cleaned up the castings....
..also, i recommend getting a small pressure pot to help get rid of the bubbles if your vents fail....they aren't too expensive these days...
for those of you that want to experiment at home i reccommend using the stuff dentists use for casting teeth....it's a soft silicon and less expensive that the usual blue silicone....it's great for making small quickie molds, however it is more brittle than the blue silicon so don't expect to get many castings out of it.....ask your dentist where you can purchase some of it....
[ This Message was edited by: Tipsy McStagger 2006-11-26 10:45 ]
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VanTiki
Grand Member (5 years) 
Joined: Nov 25, 2005
Posts: 928
From: Hawaii
| Posted: 2006-11-26 2:14 pm Permalink
I second Tipsy on the pressure pot - or if you want to get even more elaborate (I am sure you know all this already - sorry!) you can set up a vacuum pump and chamber. Depending on the cure time of your resin/polyurethane you can mix it, evacuate it, pour it, then evacuate a second time in the mold.
Great sculpture!
VanTiki
_________________
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Bowana
Grand Member (4 years)
Joined: Nov 10, 2006
Posts: 1129
From: La Mesa, CA
| Posted: 2006-11-26 6:04 pm Permalink
[quote]
On 2006-11-25 22:43, Tamapoutini wrote:
'Vahine De Milo'?
[quote]
Good one, Tama!
Thanks for the info, guys. I do have a vacuum pot that I use for silicone, and also for casting resin. Problem is that the resin will set before the vacuuming is quite done and it's hit or miss. I found that I was having the same rate of success pouring without vacuuming.
It was suggested to me by Clarita the Tiki Candle Girl to mix talc into the resin to get a slower cure time. I am certainly going to give this a try. Then I won't have so many of the dead to bury.
I agree 100% with Tipsy McStagger and VanTiki that pressure casting is the way to go. A friend of mine has one (it's an autoclave), but she lives a long way away from me, and I don't like having to make the long trip to her house unless it's for a project that I'm being paid for!!
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Tipsy McStagger
Tiki Socialite
Joined: Nov 21, 2004
Posts: 3394
From: HELL
| Posted: 2006-11-27 09:10 am Permalink
...if you can't use a pot...try tapping on/around the bottom of the mold after you pour the resin...this will loosen any air bubbles and cause them to rise up your vents...sometimes bubbles like to cling to the sides.....
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Clarita
Tiki Socialite
Joined: Sep 26, 2006
Posts: 1234
From: BA Arg
| Posted: 2006-11-27 10:27 am Permalink
Aloha Tikidav your hula gril is so cool!! and so little! and I've been thru http://members.aol.com/kelea98/dave/ too you do a lot of incredible stuff! I loved montezuma he is really great too! Congrats! Keep us posted about your progresses,Greetings!
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mundotiki
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Bowana
Grand Member (4 years)
Joined: Nov 10, 2006
Posts: 1129
From: La Mesa, CA
| Posted: 2006-11-29 8:23 pm Permalink
Tipsy: (BTW, that's a great name!) Yep, tapping on the mold will certainly loosen bubbles. Don't think I haven't tried! A light dusting of talc helps to prevent surface bubbles, and after some experimenting I found that talc mixed into the resin makes it set somewhat slower (that, combined with colder weather) so I've been having better luck.
Clarita: Glad you liked my site. Thanks for checking it out. Montezuma was one of my favorite sculptures. I sculpted it for a company called Castagna of Italy. Castagna was started by Jack Lucchesi who is mentioned in the article about the Universal Statuary Tikis in the latest issue of Tiki Magazine.
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Rum Demon
Tiki Socialite
Joined: Jun 20, 2005
Posts: 254
From: Portland, Oregon
| Posted: 2006-11-29 9:24 pm Permalink
She's a beaut! Now. MAKE AN ARMY OF THEM!!!
Also, I will totally take your one-armed hula girls. PLEASE don't throw them away. I'll reimburse you for shipping.
Nice work.
-Joe
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MUGS MUGS MUGS!!! Now on Etsy!
rumdemon.etsy.com
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Rum Demon
Tiki Socialite
Joined: Jun 20, 2005
Posts: 254
From: Portland, Oregon
| Posted: 2006-11-29 9:31 pm Permalink
Also, Mrs Demon (pro mold maker extraordanaire) says that the key to getting that right arm problem fixed is plugging up the arc vent that goes over her head. Not sure why that's there to begin with. Anyway, the air from that "rainbow" there is trying to escape through her right arm. Other than that your venting looks great. Just plug up that rainbow with some oil clay or something.
I hope the solution is really that simple. Good luck!
yaay hula girl!
-Joe
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[ This Message was edited by: Rum Demon 2006-11-29 21:33 ]
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