Polyurethane rubber has extraordinary wear resistance and it is easy to use. But, it’s the ability to poured and sprayed onto/brushed on prepared surfaces that makes it a preferred choice to make molds. Polyurethane rubber molds are not only cheap but we can also use them to manufacture highly intricate products.
Benefits of Using Polyurethane Rubber
Polyurethane is essentially liquid rubber which is largely used to make smooth molds for concrete and wax. Here are some of the key benefits of using it for molds:
- Polyurethane is usually less expensive and provides higher abrasion-resistance when compared to silicone molds.
- Concrete molds made from polyurethane rubber don’t shrink and are available in a wide range of hardness.
- These molds are reusable; which is one of the reasons manufacturers prefer them over other materials.
- Polyurethane rubber molds offer unmatchable flexibility for both small and large applications, from soaps and candles to gigantic industrial architectural components.
- They are also used to make countertops, soap dishes, drainboards, sinks, and GRFC concrete statues.
However, it is important to follow certain guidelines when using polyurethane rubber to make molds. That is in order to ensure you end up with the best product.
How to Use Polyurethane Rubber to Make Concrete Molds the Right Way
Concrete molds can be used for manufacturing technical or unique shapes from liquid concrete. The polyurethane rubber molds are perfect for this purpose. It is possible to use these molds for concrete for hard rubber stamp concrete as well as pourable concrete.
We recommend using a 75-60 or 74-45 material for concrete countertops. The first number exhibits the Shore A hardness. A 45 is quite soft while a 60 is nearly the hardness of a car. To make the mold, the polyurethane rubber can be sprayed or brushed on to the model or poured against a well-sealed model to create a mold for the countertop. We usually recommend poured blocked molds for concrete.
You can use spray-on or brush-on material but then you’ll need to come back once the rubber cures and add a “mother mold” or shell so the rubber can support the concrete during casting and retain its shape. This shell – ideally – would have to be made from polyurethane. Making poured molds can be a better option instead of sprayed/brushed on because it takes less skills to make and is more durable.
Polyurethane rubber molds can virtually last forever and allow you to make hundreds of castings – as long as you use the proper release agent and keep them out of direct sunlight. The type of release agent you use will depend on your finishing technique. Whether you want to pop a perfect slab or grind and grout it, the method will determine what kind of release agent you use and how you use it.
Contact Uniflex Inc. For Affordable Custom Polyurethane Rubber Molds
Can’t find the polyurethane rubber concrete molds to fit your project’s requirements? Uniflex Inc. can create molds based on your unique requirements and specifications. Our designers and engineers will work with you to fully customize the mold you need for any type of application.
Polyurethane’s excellent ability to adhere to metal, and our total fabrication processes allow our molds to encase metal fortifying substructures while maintaining a durable exterior to help with the de-molding process. For more information, send us a message here or call us at 248-486-6000.