The making of rubber molds throws up three different options of latex, silicone and polyurethane rubber. Understanding the properties and usage will help in choosing the right rubber for a project.
When it comes to making rubber molds, there are various options, from the natural latex rubber to synthetic compounds like polyurethane rubber and silicone rubber.
One of the first steps when making a mold will be deciding which rubber to use. While each has their own strengths and weaknesses, the choice will determine the process ahead. Let us take a look at each option –
One of the first steps when making a mold will be deciding which rubber to use. While each has their own strengths and weaknesses, the choice will determine the process ahead. Let us take a look at each option –
Latex
Latex rubber is one of the least expensive mold making materials. Yet, it is very flexible, strong, durable, tough and tear resistant. It also captures minute details very well. As the rubber is viscous enough to not run off vertical surfaces, it can be applied to models such as architectural details where they are, without needing to be thickened.
Latex molds can be used to cast plaster, polyester resin, urethane or even abrasive materials like concrete. The molds can be used again and again to produce multiple castings. They will literally last forever as long as they are stored properly.
However, it takes a long time (around 10 to 15 days) to make a latex mold. It involves brushing multiple layers of latex on the model, while allowing sufficient time in between for every layer to dry properly.
The rubber works well for creating masks too. Moreover, liquid latex is a theatrical and special effects product used to create wrinkles, scars, gashes and as an adhesive for bald caps.In a less viscous form, the same material will work for casting purposes as a latex casting rubber too.
Latex molds can be used to cast plaster, polyester resin, urethane or even abrasive materials like concrete. The molds can be used again and again to produce multiple castings. They will literally last forever as long as they are stored properly.
However, it takes a long time (around 10 to 15 days) to make a latex mold. It involves brushing multiple layers of latex on the model, while allowing sufficient time in between for every layer to dry properly.
The rubber works well for creating masks too. Moreover, liquid latex is a theatrical and special effects product used to create wrinkles, scars, gashes and as an adhesive for bald caps.In a less viscous form, the same material will work for casting purposes as a latex casting rubber too.
Polyurethane
This is a high strength rubber with excellent chemical resistance. It opens up options of varying consistencies and even a choice of firmness for the mold – from soft to medium to hard. The cost is on the average side – neither too expensive nor very cheap.
Polyurethane rubber molds are most suitable for casting polyurethane, epoxy and polyester resins. The method of making the mold is not limited to brushing or spraying; polyurethane rubber can even be poured to make solid cube molds. The mold will be ready in a few hours or a day at best.
However, polyurethane molds are not as long lasting and can even lose their shape over time.
The rubber is formulated in varied types with food safe and skin safe options also available. The translucent variant can perfectly duplicate skin surfaces. The best part is that silicone does not stick to anything but itself, negating the use of a release agent.
Silicone rubber can be used to cast different types of materials except itself. Again, the same rubber can be used to make castings too.
Consider all factors of mold making to make the right choice between liquid latex, polyurethane and silicone rubber.
Polyurethane rubber molds are most suitable for casting polyurethane, epoxy and polyester resins. The method of making the mold is not limited to brushing or spraying; polyurethane rubber can even be poured to make solid cube molds. The mold will be ready in a few hours or a day at best.
However, polyurethane molds are not as long lasting and can even lose their shape over time.
Silicone
This is an expensive material, but the superlative properties and ease of use justify the price. It is a versatile, durable and highly resistant rubber with two types of catalysts – tin and platinum – that will affect its working and usage.
The rubber is formulated in varied types with food safe and skin safe options also available. The translucent variant can perfectly duplicate skin surfaces. The best part is that silicone does not stick to anything but itself, negating the use of a release agent.
Silicone rubber can be used to cast different types of materials except itself. Again, the same rubber can be used to make castings too.
Consider all factors of mold making to make the right choice between liquid latex, polyurethane and silicone rubber.
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