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

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

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

Product ID: 48284394

Details

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

🎨Paintable & sandable finish

🌦️Weather & aging resistant

🛠️1500 PSI tensile strength

HK$307

Duties & taxes included

In stock

Sold byAmazon Hong KongDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

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Description

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

VERSATILE ADHESION - Bonds effortlessly to wood, metals, ceramics, plastics, and painted surfaces
CUSTOM FINISH READY - Can be sanded and painted to seamlessly blend with any project
UNMATCHED DURABILITY - Withstands harsh weather and aging for long-lasting protection
ECO CONSCIOUS FORMULA - Solvent, silicone, and PVC-free for a safer, cleaner application
PROFESSIONAL GRADE FLEXIBILITY - Elastic sealant that resists cracking and maintains integrity under stress

Sika Flex 521 UV is a 300 ml white polyurethane hybrid sealant designed for professional use, offering superior adhesion across multiple substrates including wood, metals, ceramics, and plastics. It boasts high tensile strength (1500 PSI), excellent weather and aging resistance, and an eco-friendly, solvent-free formula. This flexible, paintable, and sandable sealant ensures durable, waterproof joints with a clean finish, ideal for demanding sealing and bonding applications.

Specifications

ASIN	B00A9UK1TQ
Best Sellers Rank	21,668 in Automotive ( See Top 100 in Automotive ) 202 in Fillers, Adhesives & Sealants
Brand	Sika
Colour	Weiß
Country Of Origin	Germany
Customer Reviews	4.6 4.6 out of 5 stars (7,008)
Full Cure Time	3E+1 Minutes
Global Trade Identification Number	07611237142116
Item Form	Paste
Item Type Name	Sika Flex-521UV Weatherproof Hybrid Sealant
Item Weight	0.42 Kilograms
Liquid Volume	300 Millilitres
Manufacturer	Sika
Manufacturer Part Number	54864
Material	Polyurethane Silicone silicone Polyvinyl chloride
Model Number	54864
Number of Items	1
Product Warranty	Product guarantees 0 months.
Surface Recommendation	Wall, ceiling, door, window
Tensile Strength	1500 Pounds Per Square Inch
Unit Count	300.0 millilitre
Water Resistance Level	Water Resistant

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How is product pricing calculated?+

Our prices include the product cost, international shipping, import duties, customs clearance, and local delivery charges. We handle all customs and import procedures, ensuring there are no hidden fees upon delivery. PRO members receive additional benefits including free shipping.

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TrustScore 4.5 | 7,300+ reviews

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Received my product in pristine condition. Great service overall.

1 month ago

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HK$307

Duties & taxes included

In stock

Sold byAmazon Hong KongDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to Hong Kong.

Secure transaction

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Neha S.

Excellent communication throughout the order process. Product is perfect.

2 weeks ago

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Best international shipping I've ever tried. Worth every penny!

3 days ago

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