C.V.SmithARTWORKS
  • Home
  • Blog
  • Sculptures
    • Bronze
    • Clay / Apoxie Clay
    • Plaster
    • Wood
    • Stone
    • SLIDESHOW
  • Galleries
  • Contact
  • Book
  • River Arts
  • BRAF
  • Saltwater Artists
  • CMCA
  • Yarmouth Art Festival

Two Part Silicone Mold ... Problems Solved !

12/31/2015

0 Comments

 
     Constructing the second half of the two part silicone mold that I described in my last posting (12/10/15) was much more challenging than the first. The extreme curved undercuts of the second side of the object were the biggest obstacle to completing the mold successfully. The mother mold would not be able to be removed from this side unless I reconfigured the undercuts into straight sides during the rubber application process. Our instructor, Ben Asselin, recommended mixing shredded bits of cotton balls with the silicone. The addition of the cotton would make the silicone more viscous and allow me to build up specific areas without them sloughing down or becoming too dense and inflexible after curing. 
Picture
Inverted - land & marbles removed
Picture
View of undercuts
Picture
2nd attempt - undercuts eliminated
      I began this next phase of the process by inverting the first half of the mold and stabilizing it with a styrofoam supports. I removed the plasteline land (except for the pour cup) and the marble registration keys, and then applied 2 base coats of *Rebound 25 to the mold and object surfaces. After preparing a supply of shredded cotton bits, I was ready to apply the remaining layers of silicone and reconfigure the undercuts. This was my first experience using cotton mixed in with silicone, and it did not go well. I hand dipped the cotton bits into the silicone mixture and then applied it to the walls of the undercuts. The "globs" of material were hard to control - they stuck to my rubber gloves and clumped in varying thicknesses. After managing to get everything coated and built up, I made the mother mold. After the mother mold hardened I was able to remove it without difficulty, however, the silicone was another story! The silicone had gotten too thick in the central cavity, causing it to be very inflexible and almost impossible to remove the wood original...which meant it would be equally as difficult to remove a casting. My only choice at this point was to begin the second half again.
Picture
Mother mold complete
Picture
Original object removed from mold
Picture
Mold ready for pour
     My second attempt, with some minor adjustments, went much more smoothly. I dipped smaller bits of cotton into the silicone, used 2 wooden craft sticks to apply the silicone and cotton mixture, and let each layer firm up before applying the next layer. I was also careful not to get the silicone too thick on the floor of the central hollow area. Once the silicone had cured, I made a new mother mold and crossed my fingers. Problem solved! I was able to remove the wood original from the mold with relative ease. The next step was to make a cast from the mold. After securing the mold with a half dozen strong rubber bands, I positioned it in the wooden stand I made to keep it upright during the pour. I mixed a batch of *Smooth-Cast 305 (the same 2-part casting resin that I used for the one part mold described in my blog post for 10/30/15), adding a few drops of brown Smooth-On color tint. I filled the mold and, after allowing about an hour of cure time, I was able to extract a successful casting. (I also made a second casting trying out a mixture of green and brown color tinting.) Now that the challenge presented by the severe undercuts has been met and conquered, the next step will be to determine the future of these castings. Have I mentioned that I like a challenge?!
Picture
Casting revealed
Picture
Original with 2 castings
                     
​                         *
Note: Rebound 25 and Smooth-Cast 305 are products made by Smooth-on Company.
0 Comments

Your comment will be posted after it is approved.


Leave a Reply.

    Author

    Cynthia Smith, Maine artist, originally from Connecticut. Taught art at secondary level for 35 years, retired in 2004. Sculpts in bronze, wood, stone, clay & plaster. Her work can be seen at several mid-coast Maine galleries and shows.

    Picture

    RSS Feed

    Archives

    October 2022
    May 2022
    December 2021
    October 2021
    June 2021
    May 2021
    April 2021
    March 2021
    October 2020
    August 2020
    July 2020
    June 2020
    January 2020
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    February 2019
    January 2019
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    November 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    March 2017
    January 2017
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    June 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    December 2013
    November 2013
    October 2013
    September 2013
    August 2013
    July 2013
    June 2013
    May 2013
    April 2013
    March 2013
    February 2013
    January 2013
    December 2012
    November 2012
    October 2012
    September 2012
    August 2012

Powered by Create your own unique website with customizable templates.