What is the difference between acetoxy and neutral cure silicone?

Acetoxy cure silicone releases acetic acid (vinegar smell) as it cures. It bonds well to glass and glazed ceramics but can corrode metals and stain marble or natural stone. Neutral cure silicone (like the Bond It WP70) releases no acid during curing, making it safe for metals, plastics, coated surfaces and alkaline substrates like concrete and plaster. For window and door frame sealing, neutral cure is the correct choice because it won't attack the frame material or surrounding masonry.

What does low modulus mean in silicone sealant?

Modulus refers to how stiff the cured sealant is. Low modulus (LM or LMN) silicone remains very flexible after curing, typically accommodating 12-25% joint movement. This is essential for external perimeter seals around windows and doors where thermal expansion causes the joint to move throughout the day. High modulus silicone is stiffer and better for applications where minimal movement is expected, like internal glass-to-glass bonding. For frame sealing, always use low modulus.

How long does silicone sealant take to cure?

Most professional silicones skin over in 15-30 minutes and cure at approximately 2-3mm depth per 24 hours at room temperature (23 degrees, 50% relative humidity). A standard 10mm joint takes roughly 3-4 days to fully cure through. Cold weather, low humidity and deep joints all slow curing. Avoid tooling or disturbing the joint for at least the first 3 hours. Do not apply silicone below 5 degrees as it may not cure properly.

Can you paint over silicone sealant?

Standard silicone sealant cannot be painted. Paint will not adhere to cured silicone and will peel or crack. If you need a paintable seal, use an acrylic sealant or a hybrid polymer sealant like CT1 or OB1, which accept paint after curing. Some decorators' caulks are also designed specifically to be overpainted. If you've already applied silicone and need to paint, the only option is to fully remove it and reapply with a paintable product.

Which silicone colour should I use for uPVC window frames?

Match the silicone to the frame colour. White is the standard for most uPVC installations. Clear works well for glazing and visible joints where you want the sealant to disappear. Grey matches increasingly popular anthracite and slate grey frames. Black suits modern dark frame profiles. Brown is the right choice for woodgrain-effect uPVC and natural timber. The Bond It WP70 is available in white, clear, black, brown and grey, all with UV-stable colour that resists fading.

TETTPW250

Brand Tetrion Fillers Part No. TETTPW250

1 x Tetrion Powerfil 2-Part Filler White 250g

In Stock with Supplier — Usually Dispatched within 1-2 Working Days This item is sourced from our supplier. Once received, we inspect and dispatch it to you. Estimated delivery: 2-3 working days.

How does this work?

This item is sourced from our supplier network. Once received at our warehouse, we inspect and dispatch to you.

Powerfil 2-Part Filler White 250g

Name: Powerfil 2-Part Filler White 250g
Brand: Tetrion Fillers
SKU: TETTPW250
Price: 12.22 GBP
Availability: InStock

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£10.18 ex VAT

£12.22 inc VAT

Estimated delivery 2-3 working days from order

Full Manufacturer Warranty

Warranty Full manufacturer warranty

Coverage Manufacturing defects. Normal wear parts excluded.

How to claim Bring to Canterbury or Ramsgate, or contact us for collection.

Support 01843 210 459

We're an authorised Tetrion Fillers dealer — all warranty claims go directly through the manufacturer.

Powerfil 2-Part Filler White 250g

£12.22 inc VAT £10.18 ex VAT

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Powerfil 2-Part Filler White 250g

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