Is Flex Tape Waterproof?

Yes, Flex Tape is waterproof, but just how waterproof is it? 

You’ve probably seen the viral and much memed advert for Flex tape (if not take a look below), which claims that flex tape can do all kinds of incredible things. 

Here are some of things the advert claims Flex Tape can do:

  • seal up a leaking pipe without even having turn turn off the water supply
  • patch holes in roofs
  • seal holes inside pools without having to drain the pool first 
  • they even cut a boat in half and sealed it back together with Flex Tape before taking it out on the water

Impressive feats no doubt but how does flextape perform in reality?

Is it really the miracle waterproofing product it claims to be?

There are numerous videos on Youtube of people replicating the various things they do in the advert to test how well Flex Tape actually works.

You can see some of them here, here, here and here.

What you will notice in each one is that if you want seamless waterproofing then you can’t simply slap them on like they do in the advert and expect to create a perfect watertight seal.

Flex Tape is waterproof but unless you thoroughly cover the hole and tightly seal it around the edges of the hole then water will leak through.

Several of the videos feature people making big holes which they just about cover with the flex tape, with an inch or so to spare. 

The problem with this is that if the hole is big then the water pressure will push the flex tape out through the hole which will unstick the tape, so you need to have plenty of tape sticking to the bucket (or whatever it is you are fixing) to prevent this from happening.

If you to prevent any water coming through then you need to do the following:

  1. Make sure the width and height of the flex tape is at least 3 times the diameter of the hole to leave plenty of material spare to stick to the surface and create a strong seal.
  2. Press it on tightly. In the advert they quickly slap it on and give it a quick rub, if there is water flowing out of the hole then you need to spend time pressing it in place ensuring that any water trapped behind the tape is pushed out as this can weaken the seal.

Interested to find out how other types of tape fare against water? Also Read:

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