How To Tell If A Tub Is Acrylic Or Fiberglass

Bathtubs come in multiple colors, shapes, designs, materials, brands, and price points. Acrylic and fiberglass, two exceedingly popular materials, are strikingly similar. This makes telling the two apart tricky, as they share many of the same features and characteristics. If you’re unsure what type of bathtub you have in your bathroom, read this guide for a few tips and tricks to decipher its composition. 

How Do I Know If My Bathtub Is Fiberglass?

There are a few telltale signs that can indicate the difference between fiberglass and acrylic. Both materials are strikingly similar, so it can be tricky to tell the two apart. While it isn’t easy to differentiate between the two, you might be able to figure it out with a bit of sleuthing. 

Check The Color

Most fiberglass tubs and showers are white in color, whereas acrylic products come in various colors. Aside from this, fiberglass tubs are known for color fading on the bottom of the tub after years of use, so if the bottom of your shower or tub looks yellowed compared to the sides of the tub, you might have a fiberglass tub.

Feel The Temperature

Generally, acrylic feels warmer to the touch than fiberglass. So, hold your hand against the surface of the tub or shower to see if it’s cooler or warmer. You might have an acrylic tub if it feels neutral or warm to the touch. If it’s cool to the touch, you might have a fiberglass tub. 

Look At The Edges

While fiberglass and acrylic bathtubs and showers tend to be very similar, you might be able to figure out which one you have by looking at the edges of the tub or shower. Thinner edges could indicate fiberglass, whereas thicker edges could point to acrylic. 

This isn’t always a surefire way to tell, especially if you don’t have anything to compare it to, but it’s worth a shot. 

Push On The Side

Fiberglass and acrylic are reasonably flexible, but if you’re unsure what material you’re working with, you need to rule out steel or iron core tubs. Push firmly on the side of the tub. If it gives and flexes inward, you have a fiberglass or acrylic tub

Fiberglass can feel flimsier and more flexible when you push on the tub’s side, so if it gives quite a bit, it might be fiberglass. However, if the tub remains sturdy and unmoving, you likely have a tub with a metal core and a porcelain or enamel coating. 

Use A Magnet

It doesn’t hurt to rule out cast iron if you’re unsure of what material you’re dealing with. You might not be able to see any exposed metal, especially if the tub is in good shape, but this doesn’t mean it isn’t made of cast iron. 

To rule this option out, use a magnet. Hold the magnet close to the side of the tub. If it pulls toward the tub, you likely have a cast iron tub. However, in some cases, there’s a thick layer of enamel or porcelain covering the steel, so there might not be much of a pull. 

Check The Weight

If you can, try lifting the tub to check the weight of the entire thing. Of course, if the tub is fixed in place, you won’t be able to do this, but if it’s a freestanding tub, you might be able to determine the material based on its weight. 

A freestanding acrylic tub will weigh around 100 pounds on average, whereas a fiberglass tub weighs approximately 70 pounds on average. If the tub is incredibly hefty and you struggle to lift it, there’s a good chance it has a metal core. 

Frequently Asked Questions (FAQs)

How Do You Clean Fiberglass Or Acrylic Bathtubs?

The process of cleaning fiberglass and acrylic bathtubs is simple. Avoid harsh scrubbers and abrasive cleaners, as these can damage and discolor the surface of the bathtub. Stick to mild cleaners, such as a mixture of white vinegar, dish soap, and water. 

Use soft sponges and cleaning cloths to wipe the solution onto the surface of the tub. Rinse it with warm water, then allow it to dry. 

Can I Repair A Fiberglass Or Acrylic Bathtub?

Repairing minor damage on an acrylic or fiberglass bathtub is entirely doable, providing the cracks or chips don’t extend all the way through the tub. If the damage is too severe, repairing the tub might be more trouble than it’s worth, so buying a new one might be your best bet. 

All you’ll need to repair the tub is a repair kit from your local hardware store. You can find filler repair kits in the correct color to match your tub. First, you’ll need to clean the area where the damage is, then you can mix the filler according to the instructions and apply it to the crack or chip.

Generally, the filler is some type of polyester material that will bind to fiberglass or acrylic. For other bathtub materials, it might be a two-part epoxy filler. Either way, make sure you follow the manufacturer’s instructions for preparing the site, mixing the filler, and applying it to the tub. 

Be sure to give the filler ample dry time before using the tub. The label should outline a specific time frame to follow for reapplication and use times. 

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