Monday, October 19, 2015

Casting a Bas Relief in Aqua Resin or Forton

I've been busy moving into a new studio space and casting some bas relief sculptures for the shows that I'm in. I've got a quick peak into the casting process here using my Polytek rubber mold and Aqua Resin. You could also use Forton for this type of casting:

I have been quite busy moving into my new studio space. My new relief sculptures have been juried into several shows and I have been casting them. Here is a quick peak at the process:
1) Set up materials. I'm using Aqua Resin but sometimes use Forton. I have a gram scale, disposable cups of several different sizes, gloves to protect my hands, stir sticks (popsicle sticks work well), a drill with paddle attachment for mixing. I set up on newspaper for easy clean up when done.
2) I have my Polyteck 74-10 mold set up in the plaster/forton mother mold and have brushed in the first two print coast of Aqua Resin. I do two print coats to capture all the detail letting each dry before adding the next. After the first two coats of Aqua Resin have hardened I begin the laminating process. I mix batches of Aqua Resin (or Forton) and brush on - then I apply about 10% by weight of fiberglass strand. For the sides and small detail areas I'll use 1/2" and 1" strand and for the larger areas I use 3"-4" fiberglass strand. I continue to brush in coats and add more fiberglass until the entire piece is thick and strong enough. I build up an area for attaching the hanging wires as the last coat.
3-4) I let the entire piece rest over night - Forton and Aqua Resin need a 24 hour cure time in the mold to ensure it is strong before demolding. I carefully peel the rubber mold from the casting. I used 2 coats of Polytek 7300 so the piece will release but there is a fairly strong suction bond that require slow and careful efforts so as not to put too much pressure on the rubber or delicate areas of the casting. You can see the strands of fiberglass extending from the casting as I pull off the rubber.
5) The finished casting is removed from the mold and washed with soap or degreasing agent to cleanse the surface of any of the mold release. Next I will use a rasp to remove the excess flashing and fiberglass from the edges. Then I will sand those edges smooth before priming the entire piece and starting the patina.
This bas relief measures 18"w x 24"h x 3"d and the final casting weighs about 10lbs. I find the process of casting to be laborious but the finished product is a nice stone-like casting with the benefit of capturing detail like plaster but having the strength of fiberglass and light-weight.


  1. Hi Lori, I really enjoy your blog, very informative! I was wondering if you could talk about the products you use in finishing the surface work of these relief pieces. You mention priming and patina work, and sealing... I was just wondering if you have specific products you could recommend.

  2. Thank you for your comment, Micahael. There are many choices regarding patina. I'll limit the examples right now to those for Forton/Aqua Resin as seen in the bas reliefs. You can choose to add color via powdered pigments, metal powder or liquid pigments or acryllic paint colors directly to the slurry for the first 2-3 coats of casting medium. There are pros and cons to this approach and it bears experimenting. The biggest issue that I came across with this is that it can be very hard to be consistent in color/hue from coat to coat and hard to duplicate because the measurements of ingredients vary. The other issue is that adding color can sometimes cause the mixture to become a bit frothy, resulting in a bubbling and some pin-holes in the casting. The other option is to cast the piece which is then white and add coloring and patina on top. Again - many options are available. You could use metal coatings (sculpt nouveau) which contain real metal and would react chemically to patina chemicals or pigment powders, colored waxes or paints of any kind including high quality spray paint, oils or acrylics. Because I'm using a mold release, even after washing I find that patina may have a hard time bonding to the surface. That is why I use acrylic primer first. I came from a painting/illustrator background and have a lot of traditional artist supplies already at my disposal. I suggest casting small sample pieces and trying a variety of patina options because one will work better for you and your vision than others.

    I am still experimenting with the different options and combinations - most recently by coloring the casting mixture before casting and then adding additional patina on the cast piece. I'm been two busy to keep up this blog and have been posting on my webiste only...hope this helps!