Artificial Stone Manufacturing With Silicone Part 2: Materials
Adhesives and Materials for Artificial Stone Manufacturing with Silicone
Artificial stone is growing in popularity. Consumers and contractors are seeing the benefits in using this stone alternative. Not only is artificial stone less expensive than natural stone, it is also longer-lasting and can be stronger. Some of the other benefits include its malleability during design; artificial stone can be made into any shape and size, which makes it easier for the customer to get exactly what they want; and artificial stone can also be made with grooves and cavities in it so that electric wires, pipes and various wall fittings can be accommodated. And because the artificial stone is not being removed from a natural bed, as natural stone would be, no environmental precautions need to be taken.
However, when choosing the type of artificial stone, the consumer must be cautious. Different types of materials are best for different uses. Latex, silicone and polyurethane are three of the most common materials used in the artificial stone manufacturing process. Oftentimes, silicone is able to offer more advantages than latex or polyurethane. But, again, investigating what is best for your situation is the optimal plan of action.
Latex and Artificial Stone
Latex is one of the main materials that may currently be used for artificial stone manufacturing. When this material is used, it is a one-component system--in other words, the artificial stone is entirely composed of a single compound and nothing else. The stone is created by pouring about 7 layers into the mold aver the course of hours or even days. For each layer to cure, it may take several hours and increased heat--the increased heat also helps with keeping the latex flowable. Because of how it is made, there are some downsides to latex. The first downside is the price increase that has been occurring in the market over the past decade. This increase is due to the fact that it takes roughly a week to produce a finished mold and the process takes up a great deal of physical space. The second downside is that latex artificial stones, depending on their size and several other factors, can potentially shrink by as much as 40%.
Compared to latex, silicone might be a more advantageous option. For one thing, with silicone, there is no shrinkage. In addition, no heat source is needed for the use or storage of the curing or finished artificial stone. And even better, there is no need for applying multiple layers, and curing to full thickness can happen overnight at room temperature.
Polyurethane and Artificial Stone
Polyurethane is another popular material to use when manufacturing artificial stones. Polyurethane, unlike latex, is a two-component system--meaning it is constituted of two compounds, organic units joined by carbamate. With similar properties to silicone, polyurethane quickly cures. The downside of polyurethane is the extended time it takes to de-mold the artificial stones. The extra time is due to the fact that the polyurethane molds often bond to the master. The other negative side-effects to the tricky polyurethane de-molding process are that it strains the mold and makes it less durable, as well as causing physical strain to the individual who is removing the mold.
Compared to polyurethane, silicone can many times be the better choice. While the polyurethane molds can be difficult to remove from the master, silicone is known to easily de-mold. The silicone molds also last longer because there is significantly less strain put on them during the manufacturing process--while silicone molds last around 3 years, polyurethane molds only last a year or maybe 2 years. And overall, silicone is simpler to work with and is cause for far fewer complaints.
Silicone and Artificial Stone
Silicone rubbers, like polyurethane, are a two-component system--a base and a curative. This type of rubber also has the benefit of having a customizable hardness. Customers can choose on a scale between very soft and very hard. And again, like polyurethane, no heat is required during the curing or storage process. The molds can also be de-molded the day after being poured. But the molds don't have to just be poured, since Silicone can also be sprayed and brushed onto the model.
With silicone molds, a catalyst must be used to cure it. The catalyst can be either tin or platinum, but platinum is far and away the preferred choice. The main reason is that over the first two weeks after curing, the tin catalyst will cause the mold to shrink linearly, anywhere from 0.2% to 2%.
Likely the favorite silicone rubber for mold making is RTV-2. This is because the rubber type can yield perfect reproductions, can have great release properties, is very flexible and is easier to process than other rubber types.
Benefits of Artificial Stone
The benefits of artificial stone are clear. They offer consumers a viable and beautiful option to the more and more expensive natural stone. They also offer much more customizability with fitting into homes, yards and other areas. While latex and polyurethane can occasionally be the right choice for certain circumstances, silicone almost always outperforms. Not only is it more flexible than the other 2 options, but it is also a longer-lasting investment and is still less expensive than the other rubber types.