Colloidal Silica is an agent which is used to control the thixotropy or 'sag' characteristics of a resin system.
By adding colloidal silica in varying amounts to a resin mix containing the other filler types (ballons, bubbles, etc..), the handling characteristics can be controlled.
Relatively small quantities added to a resin mix containing glass bubbles or microballoons will give non-sag properties and impart easier handling.
Colloidal silica is also added with microfibres to produce a mix suitable either as a high-strength non-sagging structural adhesive (particularly for non-absorbent materials such as GRP), or as a 'high density' filler.
The inclusion of colloidal silica has the effect of increasing the hardness of the resulting mix which will create more difficulty when sanding.
For this reason colloidal silica is usually added in the minimum quantities to any mix for which sanding is anticipated.
In some applications this feature can be used as an advantage, to create a hard wearing edge or surface.
Composition: Silicon Dioxide
Appearance: White Powder, easily airborne
Particle Size:12 mcrons
Bulk Density: 50g/litre