Flex tape has been put to the test using several real-life applications and I was pleasantly surprised with the results.Even though the adhesive tape performed well in most of these tests - including underwater use - it could not tell us how long flex tape would last.

Product manufacturers market it as a temporary solution for emergency repairs.Considering this, I thought it might be helpful for anyone planning to use flex tape for repairs to learn how long it lasts.

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So, how long are we talking?

When you need to get a job done around the house quickly, flex tape comes in handy.

Due to its ability to seal and contain leaking water, there are all sorts of applications you could use it for including temporality patching leaking plumbing, sealing leaky pool inflatables, covering up cracks in outdoor lighting, and much more.

For flex seal, moisture resistance seems to be its main limitation.The only time I encountered leaks during my previous testing was when patching a PVC pipe from the exterior.

For this test, I figured the best method would be to repair a leak with flex tape and then see how long it held up.

According to other flex tape test results found online, it was evident that in many cases, the tape was able to mostly stop a leak, but sometimes a trickle of water was able to get through.Flex tape could still be useful for short-term repairs, but not as much for long-term ones.

Bucket Test

The first test involved drilling a hole saw hole of 1 34" in a bucket.Next, I patched the hole on both sides with flex tape.

In the next step, I filled the bucket with water.In the beginning, I did not notice leaks, so I left the bucket alone and checked on it periodically over the following 24 hours.


The repair seemed to stop any water from leaking initially, so I left the pipe alone in a bowl and checked on it every once in a while.

For the most part, the repair held back the water, but there was a trickle after some time.Within 24 hours, a few tablespoons of water escaped.

I’d still consider this a moderately successful test, as the repair mostly stopped the water from flowing, and performed much better than most other products I’m aware of.

Underwater Test

Then, I tested the claim that flex tape can be used underwater.As a result, I cut another hole in the 5-gallon bucket and filled it with water while covering the hole with plastic.

Once I had my flex tape ready, I deployed it underwater.When I removed the plastic holding the water back, the water freely flowed, and the hole was sealed with flex tape.


In my surprise, not only did the flex tape seal the leak, but did so without forming any drops or trickles.As I did in previous tests, I left the bucket alone and checked on it every 24 hours.

It remained intact for a long time without leaking.This was an unexpected result for me, especially since I had expected at least a little leakage to develop with time.