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Does Flex Seal Work on Copper Water Pipes? (Explained)

When sealing any surface, you might have thought of flex seal. Flex seal is an excellent liquid rubber sealant that works on almost all surfaces. 

Even this sealant prevents leakage very well. You might have used the flex seal on a plastic water pipe or other pipes.

So, you might be confused about whether flex seal works on copper water pipes. Generally, copper water pipe is slightly different from other water pipes. So, before using flex seal on the copper water pipes, you must know about this sealant’s properties.

Flex seal on copper water pipes

Flex seal works pretty well on copper water pipes. Generally, the flex seal sticks to most of the surfaces. This rubbery sealant has adhesive properties that help stick to the copper water pipe surface. A flex seal seals cracks, stops leakage, and prevents leakage from the copper surface.

However, flex seals can be of different types. For example, flex seals can be tape or spray type. Each of them might have different properties. Let’s see whether these flex seals can work on copper water pipes.

Flex seal tape:

You can use flex seal tape on the copper water pipes. This tape has adhesive material that helps stick to a surface. So, flex seal tape works well on copper water pipes.

Sometimes, copper water pipes need something that will stick to the surface from all around and keep the pipe leakage free. For this purpose, flex seal tape is an excellent solution.

Sometimes, the copper water pipe has cracks. So, the tape will be an easy solution to seal cracks in the water pipe.

Flex seal spray:

Flex seal spray also works on the copper water pipes. Generally, flex seal spray has enough adhesiveness that holds this material on the copper pipe. When you apply the spray to the surface, it might seem like a rubbery liquid.

But once the sealant is dried, it will bond strongly with the surface. So, the flex seal spray will also work to seal cracks when the spray is dried.

That’s why this spray-type flex seal will work well when the copper water pipe is dry and not flowing water.

Will Flex Seal stop a leaking copper water pipe?

Yes, Flex seal will stop a leaking copper water pipe. Generally, a leaking copper water pipe is pretty disturbing. It will reduce the water flow from the copper pipe. Moreover, corrosion and degradation of the pipe will occur from the leakage.

Flex seal tape sticks to the copper surface well and makes the surface waterproof. That means water will not pass through the tape and leak out once you apply this tape to the copper pipe.

Some other types of tapes might work instantly to stop the leakage. But the tapes will eventually peel off from the surface. On the other hand, Flex seal tape is highly adhesive. It will not peel off from the copper surface for its durability.

Moreover, Flex seal tape has strength that will withstand the water pressure. So, the tape will not peel off when the water flow rate is high. That’s why flex seal is an excellent sealant on the copper water pipe.

Does flex seal work on hot water pipes?

Flex seal works on hot water pipes. Sometimes, you might see cracks or leakage on the hot water pipe. You might think that a hot water pipe can’t be fixed with tape. But flex seal has a tape form that is strong enough to work on hot water pipes.

Hot water pipes will produce high temperatures and steam. But flex seal tape has no problem with these factors. Because this tape works on most surfaces. Moreover, flex seal tape is waterproof. So, steam will not reduce the quality of flex seal tape.

Besides, the flex seal has high pressure withstanding properties. So, it will not degrade in high pressure and temperature developed from a hot water pipe.

But before applying flex seal tape on the hot water pipe, you must stop the water flow for a while. Because water flow might affect the application process. 

After applying the tape, you can turn on the water flow. So, Flex seal will work well on hot water pipes also.

Does flex seal work on pressurized copper pipes?

Flex seal will not work on pressurized copper pipes. Generally, the Flex seal is recommended on copper water pipes where the water pressure is normal or moderate. But in pressurized copper pipes, the pressure is very high.

Flex seal or flex seal tapes have pressure withstanding property. But the withstanding property works up to a certain level. For example, the water pressure is okay for a flex seal tape to resist.

But pressurized copper pipes have such high pressures that they are incredibly high for flex seal tape. So, if you see cracks or leakage from a highly pressurized copper pipe, you should seek other ways.

Three reasons why flex seal work on copper water pipes

Now that you know you can use flex seal on copper water pipes, you might want to know why. Let’s see why flex seal works on copper water pipes.

Leakage sealing:

The primary function of the flex seal is to seal the leakage from cracks, holes, etc. Flex seal works pretty well to seal these leakages. If you want a strong sealant, you can use the flex seal tape that will stick to the copper water pipe firmly.

Moreover, air, moisture, steam, etc., coming out from the cracks and holes will also be stopped by the flex seal tape.


Another excellent property of flex seal is its waterproofing property. After applying the flex seal tape on the copper water pipe, the pipe will not leak water. 

Because flex seal has such waterproofing property that it will not allow water to pass through the flex seal tape.

Corrosion prevention:

Flex seal can also prevent corrosion and rust of the copper water pipe. Generally, cracks and pores induce corrosion and rust. 

Corrosion and rust will further degrade the copper water pipe. So, if flex seal tape can prevent corrosion and rust, it will be a great advantage.

How long does flex tape take to dry on copper water pipes?

Flex tape takes 2 hours to dry on copper water pipes. Generally, when you apply flex tape on copper water pipes, it will stick to the surface instantly. But the flex tape will take time to dry and cure completely.

Moreover, the more the flex tape dries, the stronger it gets. So, if you wait for 2 hours after applying the flex tape on copper water pipes, it will dry completely.

It will be best if you turn on the water after 24 hours. This time will make the bond stronger. Besides, the durability of the flex tape will increase. So, it is recommended to keep the flex tape dry for at least 2 hours on copper water pipes.

How do you seal copper pipes with flex seal?

You might think that sealing copper pipes with a flex seal is easy. But if you can’t do it appropriately, the flex seal will not be effective. So, let’s see how you can seal copper pipes with a flex seal.

Locating crack or hole:

First, you have to locate the crack or hole where you want to use the flex seal. If you can’t see the water splash from the crack or holes, you can search where the pipe is wet. Finding the crack or hole will make the next step easy.

Turn off the water flow:

Then you have to stop the water flow from the copper pipe. If you don’t stop the water flow, it will be difficult on the pipe. The flex seal tape will also not adhere well if the copper surface has constant water flow and leaks. Clean the crack or hole when the water flow is stopped.

Apply the flex seal tape:

Now you can apply flex seal tape on the crack or hole. You can make a full circle of the copper pipe where the crack or hole is situated. Moreover, you can use multiple layers of tape to make a strong and durable sealing.

Drying the flex seal tape:

Finally, you have to wait at least 2 hours so that the flex seal tape can dry. After drying, you can turn on the water flow and inspect whether the leakage is repaired or not.

Final Thoughts

Flex seal is an excellent rubbery sealant that works on copper water pipes. Flex seal works on almost all surfaces. Moreover, it makes a strong bond on the copper pipe. Especially the flex seal tape can stop leakage from the pipe and prevent corrosion.