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Quick Tip: What is neutral cure silicone?

When using neutral cure silicone for projects I'm often asked the difference between neutral cure silicone and other types of silicone.


There are several different types of silicone on the market, the most commonly used being acetoxy silicone and neutral cure silicone. The difference between these two types of silicone is that acetoxy silicone releases acetic acid during the curing process, while neutral cure releases a non-acidic agent. You might not think this is important, but think again.

Acetoxy Silicone

If you've ever used acetoxy silicone you will know that it gives off a vinegar smell. This can be overwhelming when used in small or confined spaces and it can take several days for the silicone to completely cure and off-gas. This type of silicone is used for sealing around fittings in bathrooms and kitchens and they are cost effective and fast-curing.

Neutral Cure Silicone

Neutral cure silicone has virtually no odour, and some neutral cure silicones have absolutely no smell whatsoever. A neutral cure silicone takes longer to cure.

What's the difference between Acetoxy and Neutral Cure Silicone?

The main difference between these two silicone products is the fact that acetoxy silicones can cause discolouration when used on certain substrates, and don't always provide an absolute seal when used on glass, aluminium and certain plastics. Additionally, acetoxy silicones can corrode metals and eat away the backing on mirrors.

Neutral cure silicone on the other hand, is excellent for use on polystyrene, glass, aluminium and PVC-U. They might be more expensive to buy and take longer to cure, but by using a neutral cure adhesive you eliminate the risk of damage caused by discolouration, etching or failure of the seal. Most neutral cure silicones are also flexible, allowing for up to twenty-five perfect movement, which makes it the ideal sealing silicone for expansion joints.

Neutral cure silicone offers better adhesion that acetoxy silicone, making them cost-effective for exterior applications.


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