WEST SYSTEM® 413 (previously called 403) is a mix of cotton microfibre and colloidal silica used as a thickening agent additive for West System brand resin and hardener when used as an adhesive. Microfibre provides superior gap filling qualities while retaining excellent surface wetting and penetration in wood bonding applications.
Also available in larger packs of 4 litres, 12 litres and 20 litres.
Have never used this stuff before. I found it easy to work with on some small filleting job and it's super light weight which was especially useful for my applications.
Thanks also to classic boat supplies for the fast and hassle free delivery.