---
product_id: 48284394
title: "Sika Flex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml"
brand: "sika"
price: "468 kr"
currency: DKK
in_stock: true
reviews_count: 13
category: "Sika"
url: https://www.desertcart.dk/products/48284394-sika-flex-521-uv-white-polyurethane-hybrid-multi-purpose-sealant
store_origin: DK
region: Denmark
---

# Multi-surface adhesion Weather & aging resistant 300 ml precision application Sika Flex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml

**Brand:** sika
**Price:** 468 kr
**Availability:** ✅ In Stock

## Summary

> 🔧 Seal smart, last long — the pro’s choice for flawless joints!

## Quick Answers

- **What is this?** Sika Flex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml by sika
- **How much does it cost?** 468 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.dk](https://www.desertcart.dk/products/48284394-sika-flex-521-uv-white-polyurethane-hybrid-multi-purpose-sealant)

## Best For

- sika enthusiasts

## Why This Product

- Trusted sika brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Eco-Conscious Formula:** Solvent, silicone, and PVC-free for a cleaner, safer workspace.
- • **Seamless Weatherproofing:** Stay worry-free with superior resistance to UV, rain, and aging.
- • **High Electrical Resistance:** Ideal for sensitive applications requiring durable insulation.
- • **Flexible & Paintable Finish:** Sand and paint over the elastic sealant for a flawless, professional look.
- • **Universal Surface Compatibility:** Bonds effortlessly to wood, metals, ceramics, plastics, and painted surfaces.

## Overview

Sika Flex 521 UV is a 300 ml white polyurethane hybrid sealant designed for professional-grade sealing and bonding. It offers exceptional weather and UV resistance, adheres to a wide range of substrates without special treatment, and remains flexible while being paintable and sandable. Free from solvents, silicone, and PVC, it ensures a durable, eco-friendly finish with high electrical resistance, making it perfect for demanding construction and repair tasks.

## Description

Sika Flex 521 UV Hybrid Sealant is specially designed for waterproofing and simple adhesives that can be used on wood, metals, primers and paints, ceramics and plastics. This Sikaflex 521 UV hybrid sealant product has very good resistance to aging and weather conditions. Among its main advantages is its excellent resistance to aging and weather conditions good adhesion on many substrates without special treatment flexible surface can be sanded and painted under non-corrosive odor high electrical resistivity without solvents or isocyanates without silicone or PVC The characteristics of the Sikaflex 521 UV hybrid sealant: density: approx. 1.4 kg/l Colour: White Application temperature: from +5 °C to +40 °C Skin formation time: approx. 30 min. Packaging: 300 ml Reference: Packaging delivered in its original packaging Tips: Application cut the nozzle to the desired gasket size. For more satisfactory results, the sealant should be applied with a suitable manual or pneumatic pump gun or unit. Use SIKA products with caution.

Review: 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.
Review: 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.

## Features

- Contains Trimethoxyvinylsilane. May produce an allergic reaction.
- Safety data sheet available on request.
- Solvent-free, silicone-free and PVC-free sealant and adhesive
- SUSTAINABILITY: Weather and aging resistant
- SUPPORTS: Adheres to a variety of substrates such as wood, metals, primed and painted metals (bicomponent systems), ceramic materials and plastics
- Can be painted and can be sanded
- Elastic and high electrical resistance; It is used by experienced professionals

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00A9UK1TQ |
| Best Sellers Rank | 31,007 in Automotive ( See Top 100 in Automotive ) 256 in Fillers, Adhesives & Sealants |
| Brand | Sika |
| Customer Reviews | 4.6 4.6 out of 5 stars (6,618) |
| Date First Available | 19 Nov. 2012 |
| Item Weight | 420 g |
| Item model number | 54864 |
| Manufacturer | Sika |
| Manufacturer part number | 54864 |
| Model | Sikaflex-521 UV (Alt) |
| Product Dimensions | 4.9 x 4.9 x 22.5 cm; 420 g |
| Special Features | BIANCO |

## Product Details

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

## Images

![Sika Flex 521 UV, White, Polyurethane Hybrid Multi-Purpose Sealant, Adhesive Sealant for Sealing and Elastic Joints, Weatherproof, 300 ml - Image 1](https://m.media-amazon.com/images/I/416nKxl0wkL.jpg)

## Questions & Answers

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

## Customer Reviews

### ⭐⭐⭐⭐⭐ Needed it fast.
*by M***L on 23 May 2025*

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.

### ⭐⭐⭐⭐⭐ Brilliant stuff very strong joint.
*by K***N on 11 June 2019*

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.

### ⭐⭐⭐⭐⭐ Solar panals glue
*by M***T on 5 June 2021*

Great stuff used to glue solar panals on my van

## 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

---

## Why Shop on Desertcart?

- 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016
- 🌍 **Shop Globally** — Access 737+ million products across 21 categories
- 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price
- 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members)
- 🔒 **Secure Payments** — Trusted payment options with buyer protection
- ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews

**Shop now:** [https://www.desertcart.dk/products/48284394-sika-flex-521-uv-white-polyurethane-hybrid-multi-purpose-sealant](https://www.desertcart.dk/products/48284394-sika-flex-521-uv-white-polyurethane-hybrid-multi-purpose-sealant)

---

*Product available on Desertcart Denmark*
*Store origin: DK*
*Last updated: 2026-03-04*