Akfix 100E RTV Black Silicone Caulk - Waterproof Flexible Sealant

In this review the Akfix 100E RTV Black Silicone Caulk is evaluated as a practical, budget-friendly sealant for home bathroom and kitchen repairs. The main reason to buy is its combination of strong adhesion and long-term flexibility, which makes it a dependable choice for joints that need to stay waterproof and elastic. The review looks at real-use strengths and a few limitations so readers can decide if this pack of black silicone tubes fits their DIY or light professional needs.

Key Features

• Universal silicone: Works as an all-purpose RTV gap filler for common bathroom and kitchen sealing tasks so you can use the same product on multiple jobs.
• Permanently elastic: Remains flexible after curing, which helps maintain watertight seals around moving joints and fixtures.
• Strong adhesion: Bonds well to non-porous building materials, providing reliable hold on surfaces like glass, porcelain, and painted trim.
• UV resistant: Resists ageing and discolouring from sunlight exposure, so external window and door seals stay presentable longer.
• Fast curing: Dries quickly enough for typical DIY schedules, reducing downtime around showers, sinks, and taps.
• Wide compatibility: Suitable for doors, windows, steel, and other construction surfaces, though avoid mirrors and sensitive metals due to acidic curing.

Who It's For

The Akfix 100E is aimed at homeowners and DIYers who need a waterproof, flexible silicone for sealing tubs, showers, sinks, windows, and doors. It is a practical choice for those who value color match and strong sealer quality when repairing or refreshing joints around wet areas.

It is not ideal for applications on mirrors or sensitive metals such as copper, brass, or lead because of the product's acidic curing. Professionals who need specialized, metal-safe or non-acidic formulations should look elsewhere.

Pros & Cons

Pros

• Good waterproofing and permanent elasticity keep joints sealed through movement and moisture exposure.
• Strong adhesion on non-porous materials reduces the chance of seal failure in typical bathroom and kitchen setups.
• UV resistance and resistance to ageing help maintain appearance and function over time.
• Available in a multi-pack format that offers value for multiple small projects.

Cons

• Acidic curing chemistry means it must not be used on mirrors or sensitive metals like copper and brass.
• Some customers report mixed build quality of the cartridge tip and variable drying times in different conditions.

Specifications

Our Verdict

The Akfix 100E RTV Black Silicone Caulk is a sensible, cost-effective option for most household sealing tasks where a waterproof, flexible seal is required. Its strong adhesion and UV resistance make it good value for bathroom and kitchen repairs, while the acidic curing means users should avoid mirrors and sensitive metals. Overall, it suits DIYers and light tradespeople who need reliable black silicone in a multi-tube pack.

Frequently Asked Questions

Can this silicone be used on mirrors?
No. Because the product cures with an acidic chemistry it must not be used on mirrors or on sensitive metals such as copper or brass.

Is the cured seal flexible long term?
Yes, the 100E is formulated to remain permanently elastic after curing, which helps seals stay watertight through normal movement.

Will it stick to porcelain and glass?
Yes. It provides strong adhesion to common non-porous materials like glass and porcelain, making it suitable for tubs, sinks, and tiles.