Food-grade silicone

01 · FOOD USE

Food equipment material, and how far that goes

Würth España certifies this silicone to NSF/ANSI 51, the standard for food equipment materials, with a toxicological analysis reviewed by NSF. Its data sheet adds four sections of FDA 21 CFR and BS 6920 for contact with drinking water. The limit comes from the manufacturer itself: it does not recommend its silicone acetates in direct contact with food or under water for long periods. The bead seals the equipment and the room, not the face the honey washes over.

02 · CURING

It cures 3 mm a day and smells of vinegar until it does

As it sets it releases acetic acid, hence the vinegar smell of the first few hours. The manufacturer's data sheet gives 10 minutes of skin formation at 23 °C and 50 % humidity, so tool the bead straight after extruding it. In depth it advances at 3 mm a day. Apply it between 5 and 40 °C: out in the apiary in January at 2 °C it will not cure properly, so that job belongs in the workshop.

03 · SUBSTRATES

Glass and stainless steel yes; the honey house concrete no

Würth gives it adhesion on glass, vitrified surfaces, ceramic tiles, plastics and stainless steel, which is what settling tanks are made of. On timber and other absorbent substrates you must first apply the silicone acetate primer, art. 0892 170. Where it does not go is on alkaline surfaces: the manufacturer rules out concrete, mortar and fibre cement. The cured bead works from -40 to 180 °C, takes UV and weather and stretches 250 % before breaking.

04 · BEFORE YOU BUY

It is supplied in transparent only: there is no white or grey version, and the manufacturer warns that transparent silicones can yellow where little light reaches them. Standard cartridge gun, not included. It cannot be painted over. Shelf life, 24 months from production.