What is Sikaflex?

If like me – armed with the knowledge of watching YouTube speedbuilds – you are looking to convert your Sprinter van, one of the first challenges is discombobulating some of the language and technical terms used. Mere weekend DIY warriors like myself often struggle to understand terms that more enlightened builders use.

Them: “Stick some Sikaflex to bond it”

Me: “Google, what is sikaflex?”

Me: “Ahhh, think I’ve got you”

I spend a significant amount of time pausing YouTube, heading over to Google and trying to find an answer to a revolutionary solution.

Sikaflex is currently a little bit of a knowledge void – it is used everywhere so by writing this, and you in turn reading this, I aim to demystify what Sikaflex is.

Screwfix say the following:-

Sikaflex is an all-weather sealant, being high strength and multipurpose construction adhesive. Sika EBT is named for its elastic bonding technology which bonds to brick, mortar, wood, metals, glass, resins and plastics. Suitable for interior or exterior use and available in various colours. It has a fast curing time but should only be applied in dry conditions. Having a high elasticity for impact and vibration means its also suitable for joint sealing and filling.

And there ladies and gentlemen is my epiphany.

Or part of it.

Flashback to another van conversion video….

Them: “Stick some Sikaflex to bond it”

Me: panicking, hitting the pause button and rewinding to a precise moment when the tube is visible

Me: “wtf, that doesn’t look like Sikaflex”

Penny drops very slowly with me at times. Turns out Sika AG trade under the brand Sikaflex and there is a plethora of bonding agents.

The clever thing about Sikaflex is the EBT technology and, given that a van will wobble, bump and vibrate it’s way through life, any compound holding vital stuff together needs to live with the van. Flexibility is key as is the ability to bond different materials and withstand extreme temperatures. Clever buggers at Sika.

Some Sikaflex products stick stuff beyond unstickiness, others seal, some bond and I’ve seen several different tubes being used for different jobs.

So what are the most common Sikaflex products used in van conversions?

My added complexity is that at times, van conversion videos get too native in their language.  On the matter of Sikaflex, there is a strange numerical patois I have no understanding of. Turns out Sikaflex is referred to by numbers more than anything else and the most popular appear to be:-

  • Sikaflex 221 – available in white, grey and black. This baby appears to pretty much do everything from fitting solar panels, sky lights and vents. The beauty of 221 – and yeah, by this stage of writing, I am a pro and will only use part numbers – is that it bonds well to a wide variety of substrates, without the need for special treatment and makes a permanent elastic seal of high adhesive strength.
  • Sikaflex 521 – available in white, grey and black. Word is that “If you need a Sealant and Adhesive for your Caravan, Motor Home or RV – Look no further.” Sorry Bob, I’m no clearer.
  • Sikaflex 999 – okay making that bit up – facetious typing but there are a lot of numbers so I’m no clearer on the different flavours only that they all seal, adhere and bond. Pick your weapon.

Most of my life I have been budget driven and a bit of a tight arse, but have slowly learnt that there is truth in that the quality of tools and materials contribute a lot to the outcome. Sikaflex (other brands are also available) doesn’t come cheap so expect to pay in the £40 to £60 range.