8 January 2014

Silicone for embedding – choose product based on geometry

There are a number of silicone products that can be used to cast things in. Silicone is an excellent choice for casting as it always becomes elastic and has very good resistance to moisture, vibration, chemicals and is a good insulator.

The vast majority of potting silicones provide very good protection, so what determines the choice of potting compound is instead how the potting itself should look - i.e. the choice becomes a matter of achieving good productivity and finding a suitable curing system.

The first thing to do is vote which one geometry the casting should have: large, small, narrow channels? In the pictures below examples of castings and which hearth systems can be considered are shown. In general, the thermosetting variants work for all types of geometries, regardless of whether they are of the 1-component or 2-component type. Heat curing in this case means that you have to go up to at least 80°C for the 2-components and 105°C for the one-components, but preferably 105°C for both.

Small inlay with silicone

Small embedment – max 6mm depth

For a small pour-in, all types of RTV silicone work: 1-component moisture curing, 2-component room temperature curing, 1-component heat curing, 2-component heat curing and UV curing.

Deep and complex embedding

Larger embedment – deeper than 6mm, but max 30mm

In larger castings, the moisture-curing silicones do not work particularly well, because they require moisture from the environment in order to cure and are therefore not recommended when the contact area with the surrounding air is very small. This applies in particular to one-component moisture-curing silicones. There is a risk that it will not harden at all, even in the long term. All other varieties of silicone for embedding work well, however.

Great casting

Large encapsulation – some surface area open to ambient air

Larger castings can be made with largely the same products as those used for deep and complex castings, i.e. 1-component heat-curing, 2-component room-temperature curing and 2-component heat-curing silicones. The choice of product can instead be determined by other factors, such as viscosity. A larger casting naturally takes longer to do. A low-viscosity product fills the space faster.

 Fully enclosed potting compound

Fully enclosed casting

If the potting compound becomes completely enclosed during curing, you can only use the addition-curing silicones; no moisture cures will work, either 1- or 2-component. Choose instead between 1- and 2-component heat curing, as well as 2-component addition curing which can cure at room temperature.

In addition to the geometry, there are additional important factors to be tuned and ranked, and for a quick and intelligent solution: contact us at Tribotec early in your project. We have extensive experience in casting and extensive knowledge of all the properties of our silicones. Together we can solve most types of requests.

Safety data sheets & documents

Here you can read more and download our product sheets, certificates, certificates & safety data sheets.