How to Make a Rubber “Glove” or “Sock” Mold

Glove molds, also referred to as sock molds, are one-piece rubber molds that can be turned back on themselves and peeled off. These molds must be thin (~1/8″) and can only be done on bas relief or models with a pyramid shape.

One of the benefits of this mold type is that a cut does not need to be made in the mold, so seam lines in the reproductions are not a concern. Another benefit is that less rubber is needed to make the mold compared to block molds, for instance.

 
 
Materials & Supplies Needed for this Project: 

The Model

The following plastic model will be used for this project.

Model for Glove Mold


 

Model for Glove Mold - Side View
Model for Glove Mold - Rear View

Step 1: Prepare the Model

Perform a test cure on the model, if necessary.

The origin of this model is unknown, so a quick test cure is done to ensure that there are not any contaminants on the model that will inhibit platinum-cured silicone. Fast-setting PlatSil ® 71-10 Silicone Rubber is used for this test.
 

Test Cure with PlatSil 71-10


 

How to test cure silicone


 
The test shows that platinum-cured silicone will cure successfully against the model.

Test Cure - Platinum 71-10 Silicone Rubber


 
Adhere the model to a stable baseboard.
 
We use PolyPoxy Quick Stick Adhesive ( discontinued), a two-part (1A:1B), fast-setting (3-5 minute cure) epoxy adhesive, to secure the model to a piece of melamine-laminated particle board.

PolyPoxy Quick Stick Epoxy Adhesive
Adhere Model to Baseboard
Adhere Model to Baseboard with Epoxy
Allow Epoxy to Cure


 
Allow the adhesive to cure and then apply an appropriate release agent.
 
A silicone mold will be made in this tutorial, so Pol-Ease 2500 Release Agent is used. For polyurethane molds, use Pol-Ease 2300 Release Agent.

Release Agent for Silicone


 
Spray the release agent onto the model and baseboard and then brush out with a dry brush to ensure even coverage.

Apply Pol-Ease 2500 Release Agent
Brush Out Release Agent

Step 2: Measure & Mix the Mold Rubber

Mold rubbers used for making glove molds should be relatively soft with high elongation properties.

For this project, we select PlatSil 71-11 Silicone Rubber. It is a soft (Shore A10), platinum-cured silicone rubber with high elongation (751%).
 
PlatSil 71-11 Silicone Rubber: The Basics

  • Shore Hardness: A10
  • Mix Ratio: 1A:1B
  • Pour Time: 20 minutes
  • Demold Time (at room temp.): 4 hours
  • Color: Blue-Green
  • Mixed Viscosity: 6,000 cP
  • Specific Volume: 24.7 in³/lb
PlatSil 71-11 Silicone Rubber - Polytek


 
How Much Rubber is Needed?

A few layers of silicone will be brushed onto the model; to start, only measure and mix the amount of rubber needed for the first layer. The second layer will not be applied until the first layer has gelled.

The ultimate goal is to reach a mold thickness of ~1/8″. For an estimate of how much rubber is needed for the first layer, determine the surface area of your model and then multiply by 1/16″. Take that result and divide by the specific volume of the mold rubber (PlatSil 71-11 has a specific volume of 24.7 in³/lb). This number will give you an estimate of the amount of rubber (lb) needed for the first layer. It is a good idea to use a bit more rubber than estimated as some of the rubber may run off of the model. A flange should also be created at the base of model, so additional rubber is needed for that.
 
Accessories

Ensure that all needed accessories are ready to go before starting the mixing process.

PlatSil 71-11 is a low-viscosity silicone, so it must be thickened for brush-on application. This silicone can be thickened with either PlatThix Liquid Thickener, TinThix Liquid Thickener or Fumed Silica.

We select PlatThix as the thickener for this project.

PlatThix Liquid Thickener for Silicone


 
We would also like to speed up the cure time of the rubber, so we make sure to have PlatSil 71/73 Part X Accelerator on hand. Accelerator is not necessary for this project, but adding just 1% Part X decreases the gel time to ~1/3 the normal gel time.
 

Accelerator for Platinum-Cured Silicone


 
Weigh Components

When all accessories, mixing containers and mixing tools are ready, use a digital scale to measure out each component.

We recommend weighing Part B into the container first as it is generally lower in viscosity than Part A and less likely to cling to the sides of the mixing container.
 

Measure PlatSil 71-11 Part B

 
 
Measure out Part A into the mixing container.
 

Measure PlatSil 71-11 Part A

 
 
Mix Parts A and B together, scraping the bottom and sides of the mixing container several times.
 

Thoroughly Mix PlatSil 71-11

 
 
Add the thickener and mix thoroughly.

For this silicone rubber, ~3% PlatThix (by weight) of the total mixed weight is a good amount to thicken for brush-on application. TinThix Thickener is a more concentrated mixture and requires about half the amount of PlatThix (~1.5%).
 

Add PlatThix Thickener


 
Add the accelerator and mix thoroughly. We add 1% Part X. If you prefer to add the accelerator prior to mixing Parts A and B together, add it to Part B and then combine with Part A.
 

Add PlatSil Accelerator

Step 3: Brush Rubber onto Model

Using a dry brush, brush rubber onto the model working from bottom to top. Working from top to bottom can increase the chances of trapped air. Using short left and right movements while brushing upwards helps to work rubber into the details of the model.

Brush Silicone onto Model


 

Brush-On Silicone Rubber

Create a rubber flange around the base of the model.
 


Create Rubber Flange


 
After a thin layer of rubber has been applied to the entire model, allow the rubber to gel before moving on to the second layer. Application of the second layer should not disturb/move the first layer.
 


 
When the first layer has gelled, measure and mix a second batch of rubber and brush it onto the model.

Apply Second Layer of Silicone
Brush On Second Layer
Second Layer of PlatSil 71-11
Allow Second Layer of Silicone to Gel


 
Allow the second layer to gel and then mix up another batch for the third and final layer. The amount of layers necessary will vary depending on individual technique.

Apply Third Layer of Silicone
Brush on Third and Final Layer of Silicone


 
Allow the final layer to cure.

Allow Final Layer to Cure

Step 4: Make a Mold Shell

Thin blanket molds must be backed with a rigid support shell or nest, otherwise they”ll deform during the casting process.

For this project, we choose to make a one-piece flexible foam “nest”.

To begin, trim the flange. We will be using a PVC pipe to cast the foam, we so we trim the flange to the same diameter as the pipe.
 

Trim Rubber Flange


 
Secure the two halves of the PVC pipe together with tape.
 

PVC Pipe to Make Foam Shell
Align PVC Pipe
Secure Pipe Together
Secure Two Halves Together
Foam Mold Shell Form


 
Coat the inside of the pipe with paste wax so it releases easily from the foam. Also lightly coat the silicone mold with paste wax.

Apply Paste Wax to Pipe and Mold
Apply Paste Wax to Inside of Pipe


 
Place the pipe over the mold and secure it to the baseboard with tape.

Place PVC Pipe Over Mold
Secure PVC Pipe to Baseboard

Secure Form to Baseboard


 
For a more dense, compact foam, close the top of the pipe with a board and make some vent holes.
 
We leave the top of the PVC mostly open.


Ready for Foam Shell


 
PolyFoam F-3 is a self-skinning, flexible polyurethane foam. It has a 1A:2B mix ratio (by weight), a 1.5-minute rise time and a 10-minute demold time. This foam has a free-rise density of 3 lb/ft³, but should be molded at 5 or 6 lb/ft³ for good results.

PolyFoam F-3 Flexible Casting Foam


 
To determine how much foam (lb) is needed, multiple the volume (ft³) of the space you’d like to fill by the desired density of the molded foam (5 lb/ft³).

Carefully measure out Parts A and B (1A:2B), combine and mix thoroughly.
 

Measure PolyFoam Flexible F-3 Foam Part B


 

Measure PolyFoam Flexible F-3 Foam Part A
Mix PolyFoam F-3


 
It is important to work quickly when using foam, especially in hot/humid environments. Immediately after mixing, pour the foam into the PVC pipe.

Pour Foam into the Pipe
PolyFoam F-3 Expanding


 
Because we did not close the PVC pipe, the foam rises out.

PolyFoam F-3 in PVC Pipe

Step 5: Demold

When the foam has cured, remove the tape and pipe.
 


Allow Foam to Cure Then Remove Pipe


 

Cut Tape on Pipe
Open PVC Pipe
Remove Foam Nest


 
Then remove the mold from the foam nest.

Remove Mold from Foam Nest
Remove Rubber Mold from Foam Shell


 
After removing the mold, it is a good idea to squeeze the foam with your hands. This will burst the cells and allow atmospheric air info the foam to prevent shrinking.

Massage the Foam to Prevent Collapsing


 
To remove the glove mold from the model, we recommend first applying a silicone release or soapy water to the exterior of the mold to allow it to slide easily against itself.

We apply Pol-Ease 2300 Release Agent. If you only have Pol-Ease 2500 Release Agent in stock, it will also work, but a larger amount may be required.
 

Spray Silicone Release onto Glove Mold


 

Spray Pol-Ease 2300 on Rubber Sock Mold


 
After application of silicone release or soapy water, begin to peel back the mold starting at the bottom.

Peel Glove Mold Off of Model
Peel Back Rubber Glove Mold


 
It may be helpful to place the mold on the corner of the table for leverage.

Peel Glove Mold Off of Model
PlatSil 71-11 Silicone Glove Mold
Remove Model from Mold


 
Trim the foam nest and make sure that it is level.

Cut Foam on Band Saw


 
To ensure alignment of the mold and foam nest when casting, create a simple notch in the mold and foam to properly align the two elements each time.

Key the Rubber Mold and Foam Shell
Key in Silicone Mold and Foam Nest


 
The mold is now ready for casting!

The Finished Mold with Foam Shell

Step 6: Casting

There are many materials that can be cast in silicone molds. Some examples include polyurethane resin, polyester resin, polyurethane foam, epoxy resin, wax, plaster and concrete.

The following example utilizes EasyFlo 60 Liquid Plastic , a fast-setting polyurethane plastic. This plastic has a 1A:1B mix ratio (by volume), 2 to 2.5-minute working time and 15 to 30-minute demold time.

To cast this figurine, we measure and mix the resin and then pour about half of it into the mold.
 

EasyFlo 60 Liquid Plastic Casting


 
We tilt the mold back and forth a few times to help release any trapped air bubbles and then pour the remainder of the EasyFlo 60.
 

Complete Resin Pour


 
When the EasyFlo 60 has cured, we remove the figurine the same way that the original model was removed.

Demold EasyFlo 60 Plastic Casting
Peel Back Glove Mold to Remove Casting
PlatSil 71-11 Sock Mold

 
Remove EasyFlo Resin Casting from Mold


 
The EasyFlo 60 reproduction is pictured below next to the original.

Silicone Mold for Figurine Reproduction
EasyFlo 60 Resin Casting and Original Model


 
EasyFlo 60 liquid plastic can be dyed with PolyColor Dyes or the cured plastic can be painted after-the-fact.

The figurine below was colored with a small amount of Brown PolyColor Dye and then Sculpt Nouveau’s Black Wax was applied and wiped away with a paper towel to highlight the details of the casting.
 

EasyFlo 60 Plastic and Black Wax


 

Sculpt Nouveau Wax on EasyFlo Resin
Glove Mold - EasyFlo Plastic - Front View
Glove Mold - EasyFlo Plastic - Rear View

Do you have questions?

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