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Silicone Glove Mold and Fiberglass Mothermold

November 14, 2017

With larger pieces, it is more cost effective to make a glove mold rather than a large block mold. A glove mold is also less cumbersome than a large block mold. Glove molds do need a supportive structure since they are thinner than a block mold, so I will make an epoxy and fiberglass mothermold to support the finished glove mold. Additionally, the piece I picked for this project has a lot of detail so I will be using a silicone diluent to pick up all the detail and decrease the risk of air bubbles.

Materials needed:

Your work area:

  • Clean, level work surface, covered in paper or plastic for easier clean-up.
  • All materials comfortably within reach.

Project steps:

  • To start, I set my original on the cardboard, right in the middle. The mold needs to have a lip at the base. The cardboard is something that the silicone can be applied to and will peel off easily when I’m done.

  

  • Because of the detail on the original, I am using silicone diluent to thin the rather viscous brushable silicone. The diluent is added to the white silicone base (Part A) up to 10% by weight. For the first coat, I weighed out 150 grams of silicone Part A and added 15 grams of the silicone diluent and mixed well. The total weight of my silicone is now 165 grams and the catalyst needs to be added at 10% of the total weight. I rounded 16.5 grams up to 17 grams because my scale doesn’t do half grams. This silicone isn’t finicky or exacting, so you can round up or down. It will turn out fine either way.
  • As I applied the silicone using a 1 inch chip brush, I really focused on getting into all the nooks and crannies of the piece. This silicone has a 45 minute pot life which allows me to take my time and makes sure there are no air bubbles in my first coat of silicone. Any air bubbles in the first coat will be recreated as lumps in every casting. So while I try to avoid air bubbles in every subsequent coat, it is extremely important to not have any in the first coat.

  • I let the silicone cure for 24 hours. For the next two coats, I mixed 150 grams of Silicone Part A, 8 grams of silicone diluent (5%), and 16 grams of catalyst. The 2nd and 3rd coats can go on a little thicker to help build the mold. I also focused on making a “lip” all the way around the piece, extended about an inch out. I always let each coat cure for 24 hours before applying the next coat.

 

  • For the 4th and final coat, I went back to adding the silicone diluent at 10% because I want this coat to flow more into the remaining detail and be mostly smooth on top. This makes it easier to do the epoxy and fiberglass mothermold. I let the silicone cure for 24 hours before moving on to the next step.

  • Now that I have a nice smooth glove mold, it’s time to make an epoxy and fiberglass mothermold to support it. First, I peel the whole thing off the cardboard, taking care not to peel the silicone off the piece. I set it back down on the plastic covering on my work station. The epoxy peels easily off the plastic, but would stick to the cardboard.

 

  • I’m using our 6 oz plain weave fiberglass. Since this piece is mostly flat and not too large, I’m only going to do one layer of resin and fiberglass mothermold. If the piece was larger or more vertical, I would do several layers to give it more support.
  • I trimmed the fiberglass to fit comfortably around the mold and then set it in place. I pressed the fiberglass into the contours of the mold. This was fairly simple because I filled in most of the detail with the last coat of silicone.

 

  • Next I mixed 4 oz of AeroMarine Products 300 Epoxy Resin with 2 oz of AeroMarine Products 21 Epoxy Hardener. I stirred it vigorously, taking care to scrape the sides and bottom of the mixing container, for several minutes. Then, I dribbled the epoxy around the edges of the fiberglass to hold the edges down. I used my chip brush to apply more epoxy to fiberglass, saturating it completely.

  • If I needed to do more layers, I would let this set up for at least 12 hours and then follow the same procedure, this time laying the fiberglass in the opposite direction for added strength. Since I’m only doing the one layer, I just let it cure for the full 24 hours before coming back to remove the fiberglass mothermold and de-mold the piece.
  • The raw edges of fiberglass and epoxy were very sharp, so I used heavy duty scissors to trim and shape teh fiberglass mothermold.

  

  • Once the sharp edges were trimmed away, I carefully pulled the mold (with the piece still inside) away from the fiberglass mothermold. Then, I carefully removed the silicone mold from the piece.

  • If I was going to cast, I would then sit the mold back into the mothermold for the casting.

Done! This was just a simple glove mold with epoxy and fiberglass mothermold. The same method can be applied to larger and/or more complex projects. As every project is different, give us a call, toll-free, at 877-342-8860 or drop us an email at info@aeromarineproducts.com if you have questions about your own project!

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