What Will Flex Seal Not Stick To? (Complete List)
Flex seal is an excellent rubberized coating that can stick to many surfaces. It is primarily used for making surfaces waterproof or to cover up leaks and cracks.
But there are some surfaces that will not work with the Flex seal. In this article, we will be discussing the list of things to which the flex seal doesn’t stick.
What Will Flex Seal Not Stick To?
In general, the Flex seal does not go well with surfaces that are under constant heat and pressure. The ingredients of the flex seal will not hold well in high-temperature or high-pressure scenarios. Therefore, surfaces like gas lines, tires, high-pressure hoses, etc. will not hold the flex seal well. Also, if a surface has a water-repellent coating, grease, or hard chemicals, then the flex seal will not stick to it.
The list of surfaces compatible with flex seal is a long one. Because it can pretty much stick to anything except the above-mentioned conditions. Even if compatible surfaces are present under those situations, the flex seal will not stick to them.
Let us discuss the reason for the flex seal not sticking to those surfaces in more detail.
Surfaces Under Heat and Pressure
We know that a flex seal is made up of rubberized polymer with some additives. Polymer materials cannot withstand much heat and they tend to transform into liquid soon under pressure.
Flex seal can only withstand 140⁰F or 60⁰C at the maximum. Under pressure, this temperature will still drop down and it will only withstand less heat.
So, if you are using flex seal spray or liquid or any other flex seal product, make sure to use it on surfaces that don’t go beyond 140⁰F and don’t stay under constant pressure.
A good example of such a surface is a tire. Tires usually undergo a lot of friction which generates large heat. Also, it stays under a lot of pressure too. So, if you apply a flex seal to a bike or car tire, it will not hold up and will deteriorate soon.
Similarly, surfaces like high-pressure gas lines and high-temperature oil lines will also damage the rubber polymer material of the flex seal. So, you will have a very poor seal and it will be dangerous too.
Therefore, any surface that is under constant heat and pressure can be avoided even if the flex seal is compatible with the surface material.
Surfaces with Water Repellant Coating
Flex seal is basically an adhesive. Water-repellant coatings create a hydrophobic surface where the adhesive cannot adhere to the surface.
When water or water-based adhesives are applied over the hydrophobic surfaces, the surface tension is very high making the liquid acquire the least surface area.
Due to this, the water or glue doesn’t get absorbed onto the surface and it will not stick to it. So, when you apply an adhesive, it will not stick to the surface. The flex seal will not dry properly creating a strong bond with it.
Surfaces that are coated with silicone-based materials tend to be hydrophobic and flex seal will not stick to it effectively.
Also, the polymer material in the flex seal doesn’t bond with hydrophobic surfaces well and thus making it difficult to use over them.
Grease and oil surfaces are also hydrophobic in nature. More than water molecules, oil, and grease attract other oil molecules strongly. Adhesives cannot bond over greasy surfaces.
Flex seal has both adhesive and polymer-based material. So, oil or grease doesn’t attract the molecules well and it will be practically impossible for the flex seal to stick to it.
Unless you clean the surface and remove the hydrophobic coatings or grease, you cannot use a flex seal on top of it.
Surfaces Coated with Hard Chemicals
There are some chemicals that can degrade the polymer structure of the flex seal. If you have surfaces that have these chemicals applied or come into frequent contact, then you cannot use a flex seal on them.
For example, acids can easily break the bonds of the polymer present in the flex seal. Even if it is a mild acid, it can have some effect on the cross bonds and lead to the degradation of the seal.
Therefore, if your surface has any hard chemicals, you must abstain from using a flex seal over them.
Apart from the above-mentioned surfaces, you can use flex seal over any kind of surface which includes metals, tiles, wooden surfaces, concrete, bricks, fabrics, glass surfaces, plastic products, ceramics, and vinyl.
Can You Use Flex Seal Underwater?
Not all flex seal products can be used underwater. For example, you cannot apply flex seal spray or liquid under water. But you can use flex seal paste underwater.
Flex seal paste doesn’t dissolve or get mixed underwater. So, you can use it to seal cracks and crevices on surfaces underwater.
Apart from these, you can use flex seal liquid over wet surfaces but not inside a water-filled surface. So, if you want to seal anything underwater, you have to use flex seal paste.
Conclusion
Flex seal covers a lot of surfaces and it is almost compatible with anything. But some surfaces might not be suitable for it and you have to avoid using Flex seal on them. This list of non-compatible surfaces will help you decide how to use the product effectively.
