How to Seal Styrofoam: Make it Waterproof

Styrofoam is the expanded version of polystyrene and is used in doing craft projects, food packaging boxes, theater sets, and various other things too. So if you are planning to coat the styrofoam, then you need to understand and learn the process of sealing it. As it is a bit tricky and method-wise, it is preferable to follow the steps thoroughly. There applying regular paint won’t help you as the styrofoam will eat the paint or melt it. So for adequately sealing the styrofoam, you need to paint with a smooth surface and appropriate paint. 

So this is an article with step by step method on how to seal styrofoam easily and quickly:

Things you will need

• A Large Bowl
• Plaster of Paris (POP)
• Large Paintbrush with good quality
• Plastic Tablecloth

How to Seal Styrofoam

So now that you have collected all the essential things for sealing let’s start the coating process. It is simple yet complicated, so don’t lose your focus anyway.  

Step 1. 

The first thing you need to do is cover the work area where you are going to seal the styrofoam. For covering the surface you will need a plastic tablecloth, you can take a normal dirty fabric or any of your choice. Working with Plaster of Paris creates lots of dirty and dusty surfaces that leave films on the area too; thus, here cover the whole working space would be great. 

Step 2. 

Now take a large bowl and mix the two parts of POP. Carefully remove all the lumps and dirt if you see any or seem like that. Lumps always affect adversely on the bonding and thus leading to uneven surface on your styrofoam. This one is an important step to make sure you do not make any mistakes here. 

Step 3. 

Now with the help of a large and good quality paint brush, you have to start applying the Plaster of Paris on the styrofoam thoroughly. Make sure you cover the styrofoam entirely and do not leave any place just in case. And now all you have to do is allow the plaster of Paris to dry completely. Once it is dry, you will see properly how the OP has stuck on the styrofoam. Repeat the application of POP for three such coats. 

And here it is done. You have successfully sealed the styrofoam. It was easy yet complicated. If you leave spaces in the first application, then the surface is not well-formed and smooth. Thus taking care of the very first step is essential. 

Is styrofoam waterproof?

Styrofoam is the extruded foam of polystyrene, and you can also name it as Blue Board. The manufacturing and making of the styrofoam are used in roofs, walls, foundations, water barriers, and much more. Well, styrofoam is used in a variety of materials and has distinctive colors too. Yet, researches say that styrofoam is not completely waterproof. Though it is used to prevent water leaks, there are chances of not being useful in the longer run. 

Also, while using such active substances, you have to take the necessary precautions. So next time, when you are dealing with styrofoam, let the professionals be in charge and do not try things by yourself. It is better to keep the experts. Stay safe; stay creative. 

Stephen Lombardo

Hello, I am Stephen Lombardo. I want to expand my automotive business. I have one large vehicle garage, and I like to do a car wash, repair and joint the cars, and motors parts. If you want to buy any car or vehicle accessories, feel free to reach out with our contact email.

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