SikaFlex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml

SikaFlex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml

Q: Can this be over sprayed with a clear lacquer to protect from discolouration or would the lacquer just peel off in time?

My answer to your question is no. Because of the way sikaflex works is that it doesn't dry totally so it remains flexible to take up movement. This leaves the seal intact and waterproof. Paint or lacquer will crack a fall off in my experience

Q: can it be smoothed with soap water?

I've just used it to seal my lockers on our caravan. Used a mastic gun. I would not personally use soap to smooth it over. Once on its better than no more nails. But like I say I used it for our caravan.. Excellent stuff

Product ID: 48284394

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Details

Colour
Weiß
Brand
Sika
Item weight
0.42 Kilograms
Liquid volume
300
Full cure time
3E+1 Minutes

🧪Solvent, silicone & PVC-free formula

🌦️Weather & UV resistant

🛠️300 ml precision application

Frequently Bought Together

Sika Flex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml

Sika Sikaflex-522 Caravan And Motorhome Adhesive Sealant – Weather And Mould Resistant – White – 300ml

Description

🔧 Seal the deal with pro-grade durability and style!

ECO SMART FORMULA - Solvent, silicone, and PVC-free for a cleaner, safer workspace and environment.
VERSATILE ADHESION - Bonds effortlessly to wood, metals, ceramics, plastics, and painted surfaces—one sealant to rule them all.
PROFESSIONAL FINISH - Paintable and sandable for seamless integration into any project.
ULTIMATE WEATHERPROOFING - Stay worry-free with superior UV and aging resistance for long-lasting seals.
ELASTIC ELECTRICALLY RESISTANT - Flexible yet tough, perfect for dynamic joints and electrical insulation needs.

SikaFlex 521 UV is a 300 ml polyurethane hybrid sealant designed for multi-purpose use. It offers exceptional weatherproofing and UV resistance, bonds to a wide range of materials including wood, metals, ceramics, and plastics, and features a solvent-, silicone-, and PVC-free formula. Paintable and sandable, it delivers a professional finish with elastic and high electrical resistance, making it the go-to choice for experienced professionals seeking durable, versatile sealing solutions.

Specifications

Manufacturer	Sika
Brand	Sika
Model	Sikaflex-521 UV (Alt)
Product Dimensions	4.9 x 4.9 x 22.5 cm; 420 g
Item model number	54864
Manufacturer part number	54864
Special Features	BIANCO
Item Weight	420 g

Have a Question? See What Others Asked

Can this be over sprayed with a clear lacquer to protect from discolouration or would the lacquer just peel off in time?

can it be smoothed with soap water?

Reviews

M**L

Needed it fast.

Needed this specific product for a client task. As always the main criteria was getting the item quick as this was a urgent task.Delivery was quick and well packaged. The product worked well but as this product was a requirement by the customer I don't think it's fair to compare it to other products. It has remained flexible and provided a weatherproof seal on the component.

23.05.2025

K**N

Brilliant stuff very strong joint.

Easy to use, full size solar panel fitted to the caravan glued in 6 positions very strong joints fitted Saturday morning could not move it Sunday morning, no holes required in the caravan roof.

11.06.2019

M**T

Solar panals glue

Great stuff used to glue solar panals on my van

5.06.2021

L**N

Best sealant on the market

Use this before on our caravan would highly recommend

6.05.2021

G**N

Sikaflex

Perfect for the job putting solar on campervan roof

9.04.2021

S**E

Good sealant for motorhome, and general outdoor settings

Great sealant for motorhome

28.07.2021

P**P

keep out the damp

Not tried this batch but last lot very good

20.12.2019

A**R

Yes

Excellent

1.01.2020

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Trustpilot

TrustScore 4.5 | 7,300+ reviews

Vikram D.

The MOLLE sheath is of exceptional quality. Very happy with my purchase.

2 weeks ago

Rajesh P.

Customer service was outstanding when I had questions about the product.

2 days ago

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