Sculpture Community - Sculpture.net  

Go Back  Sculpture Community - Sculpture.net > Sculpture Roundtable Discussions > Sculpture focus topics
User Name
Password
Home Sculpture Community Photo Gallery ISC Sculpture.org Register FAQ Members List Search New posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 10-19-2008, 03:41 AM
jcusalove jcusalove is offline
Level 1 user
 
Join Date: Oct 2008
Location: usa
Posts: 2
Please help with Latex Casts in Plaster Molds.

Hi!
I'm new here and have been scuplting/molding & casting for over a decade. I've been mainly doing mask latex casts in Ultracal 30 molds and have had the same problem every time. Gradual degradation of the molds and thus the casts.

I've tried to find other means of preserving the mold life, but have yet to find anything that actually works. Sea Lube was suggested, but never did anything but cause problems so I stopped using it long ago. No one I'ved talked to can recommend anything else as a mold release, so I've stopped using any at all and just pour the latex straight in and peel it out. Over the course of a year (approx 60-100 casts), the casts look quite poor compared to the originals. Thus, I have to do a resculpt and remold...which REALLY SUCKS!!!

If anyone knows of an alternative to Ultracal 30 that works just as well but doesn't degrade and is COMPLETELY COMPATIBLE with mask latex, I'd GREATLY appreciate it!

Thanks for your time and suggestions!
jc
Reply With Quote
  #2  
Old 10-20-2008, 02:32 PM
SPRINGFIELD SPRINGFIELD is offline
Level 10 user
 
Join Date: Jul 2006
Location: BURBANK CALIFORNIA
Posts: 731
Re: Please help with Latex Casts in Plaster Molds.

Quote:
Originally Posted by jcusalove View Post
Hi!
I'm new here and have been scuplting/molding & casting for over a decade. I've been mainly doing mask latex casts in Ultracal 30 molds and have had the same problem every time. Gradual degradation of the molds and thus the casts.

Over the course of a year (approx 60-100 casts), the casts look quite poor compared to the originals. Thus, I have to do a resculpt and remold...which REALLY SUCKS!!!


jc
Since your are making a lot of copies it might be worth it to use something that you can easily remake your Ultracal 30 molds off of. For instance when you pull off your Ultracal mold instead of casting latex cast a solid silicone model {or other rubber model] that way when the Ultracal 30 mold wears out use the silicone model to reproduce a new Ultracal 30 mold. Also that way you can make lots of Ultracal 30 molds to increase production.
Another thing you could do is when the Ultracal Mold wears out you could
slip cast [or press cast a water based clay model} and than just refine the detail. I'm thinking your probably doing that already.
Anyway just my $0.02.
Reply With Quote
  #3  
Old 10-27-2008, 04:01 PM
Andrew Werby Andrew Werby is offline
Level 10 user
 
Join Date: Dec 2005
Location: Oakland, CA
Posts: 647
Re: Please help with Latex Casts in Plaster Molds.

Quote:
Originally Posted by jcusalove View Post
Hi!
I'm new here and have been scuplting/molding & casting for over a decade. I've been mainly doing mask latex casts in Ultracal 30 molds and have had the same problem every time. Gradual degradation of the molds and thus the casts.

[The molds sound like they're wearing out. The degradation of the latex is a separate issue (usually due to oxidation), although if you're casting into molds that have a lot of porosity due to repeated casting of the ammonia-based latex into them, that would add some unwanted positive pimples and warts.]

I've tried to find other means of preserving the mold life, but have yet to find anything that actually works. Sea Lube was suggested, but never did anything but cause problems so I stopped using it long ago. No one I'ved talked to can recommend anything else as a mold release, so I've stopped using any at all and just pour the latex straight in and peel it out. Over the course of a year (approx 60-100 casts), the casts look quite poor compared to the originals. Thus, I have to do a resculpt and remold...which REALLY SUCKS!!!

If anyone knows of an alternative to Ultracal 30 that works just as well but doesn't degrade and is COMPLETELY COMPATIBLE with mask latex, I'd GREATLY appreciate it!

Thanks for your time and suggestions!
jc
[Have you ever used a silicone mold rubber? It's fairly impervious, and wouldn't degrade like the materials you've been using. You could use it two ways: first like was suggested already, where you make a permanent casting from the plaster mold before using it for the latex. That way you can make more UltraCal molds off of it when your plaster starts showing wear. Do this if you need the absorbancy of the plaster to form a good latex layer.

The second approach would be to make a silicone rubber negative mold and cast the latex into that. It won't absorb anything from the latex, but that's probably not necessary. I think it would last a lot longer than the plaster molds; the main problem silicone molds have is a tendency to rip as they get older. Platinum-cure silicones are less susceptible to that than the less-expensive tin-cure systems, although they are more temperamental as well, often refusing to set on surfaces contaminated with various oils or other rubber compounds.]

Andrew Werby
www.unitedartworks.com
Reply With Quote
  #4  
Old 11-08-2008, 11:42 AM
realsculpt's Avatar
realsculpt realsculpt is offline
Level 6 user
 
Join Date: Sep 2005
Location: USA
Posts: 131
Re: Please help with Latex Casts in Plaster Molds.

how many casts are you making? if you are doing less than 50, the only reason for the mold desinigrating is a bad plaster mix or mixing habits.

I would recommend doing about 50 to 75% water with "acryl 60" an acrylic binder to the ultra-cal. you can seal your mold also with clear shelac spray.

the other option would be epoxy-cal from Adtech, its an epoxy surface coat for ultracal, it will make a really strong permant surface on the ultracal thats tempeture resistant.

most people use hydrocal for masks and get about 25 to 50 pulls per mold, i know some will do a soft filled latex master, and remold that as a one piece mold when ever they need a new cast. you could even do a fiberglass gel coated mold that woul be really permentant.

Stay away form silicone and urethans the latex wont stick to the surface long enough to dry, it will just bead up.

good luck and try calling places like

FXwarehousinc.com
monstermakers.com
burman industries

Seth
__________________
seth
www.forensicsculpting.com
www.realsculpt.com
Reply With Quote
  #5  
Old 11-08-2008, 07:54 PM
Daniel Daniel is offline
Level 8 user
 
Join Date: Jun 2006
Location: Los Angeles, CA
Posts: 206
Re: Please help with Latex Casts in Plaster Molds.

Quote:
Originally Posted by realsculpt View Post
how many casts are you making? if you are doing less than 50, the only reason for the mold desinigrating is a bad plaster mix or mixing habits.

I would recommend doing about 50 to 75% water with "acryl 60" an acrylic binder to the ultra-cal. you can seal your mold also with clear shelac spray.

the other option would be epoxy-cal from Adtech, its an epoxy surface coat for ultracal, it will make a really strong permant surface on the ultracal thats tempeture resistant.



Seth
The acryl 60 will help to strengthen the plaster. I don't think shellac or epoxy sealers, or fiberglass molds will be much good to you, though, since the big advantage of using plaster is that the porous plaster mold absorbs moisture from the latex when you slip-cast a mask. This creates a skin on the inside of the mold. The porosity of the plaster also helps the mask dry significantly faster than it would in a fiberglass or sealed-surface plaster mold. As has already been mentioned, your best bet is probably to cast a good "molding master" copy of your mask to use to make additional molds from if it becomes necessary. You can make a thick latex casting and fill it with expanding flexible foam before demolding. Actually, it might be better to cast this with a silicone skin rather than latex, since latex tends to shrink away from the mold surface when it dries and might become slightly distorted when you add the expanding foam.

hope this helps.
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


Sculpture Community, Sculpture.net
International Sculpture Center, Sculpture.org
vBulletin, Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Russ RuBert