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Effective Tips to Remove Rust Stains from Fiberglass

How to Remove Rust Stain from Fiberglass Tub

Rust Stains from Fiberglass

Tubs can be a big source of rust staining. Whether you have a place you like to soak your feet, or if you just have to bathe the kids, when you leave with wet feet and it is raining outside, rust will start to form on your tub.

 To prevent this scenario, we recommend wiping down the dry tub before showering to remove moisture. Even though there is nothing wrong with a little rust on your fiberglass tub, it can become unsightly over time. Here are some tips on how to remove rust stains from fiberglass tubs and keep them shining like new.

What is rust?

Rust is a chemical reaction that occurs when iron or steel comes into contact with oxygen. The iron molecules lose electrons and become positively charged ions, while the oxygen molecules gain electrons and become negatively charged ions. These newly formed ions are attracted to each other and bond together. This new compound is called iron oxide rust, which forms a protective layer over the metal surface that prevents further corrosion from happening.

What Causes Rust on Fiberglass Tubs?

Fiberglass is often used as a bathtub and shower material because it is non-porous, impact resistant, and relatively inexpensive. However, fiberglass tubs are susceptible to rusting if they are not properly maintained or if they are damaged by water leaks or other factors.

The main causes of rust on fiberglass tubs are:

The use of a harsh cleaning product. The most common cause is the use of bleach-based cleaners. Bleach can cause corrosion to metal parts, and it also bleaches out stains. However, over time it will damage fiberglass surfaces as well.

Use of an abrasive cleaner. This includes scouring pads and other harsh household cleaning tools. They can scratch the surface and remove Gelcoat from your fiberglass surface, leaving behind dull spots or small scars.

Poor maintenance habits. If you do not clean your bathtub regularly, you may find that rust has started to form around the drain opening or other areas where water sits for long periods at a time.

How to Remove Rust Stain from Fiberglass Tub

Lemon and Salt

To remove rust stains from the fiberglass tubs, you can try lemon and salt. Lemon is acidic and will help to neutralize the acidity in the rust. Salt is a good abrasive that will help to remove the rust stain.

Steps to remove rust stain from fiberglass tub:

  • Put some salt into a cup and add enough lemon juice to make a paste.
  • Apply this mixture to the rust and scrub it gently with a soft brush or cloth until all the rust is removed.
  • Let this sit disturbed for at least 24 hours the longer you leave it, the better.
  • After 24 hours, use a sponge or scrubber to remove all of the lemon juice and salt from your tub.
  • Rinse with water and wipe dry with a clean towel

Baking Soda

It is a fantastic product for general use around the house and can be used to remove rust stains from fiberglass tubs.

Baking soda is a great cleaning product that can remove rust stains from fiberglass bathtubs. It works by absorbing the stain and leaving your tub looking clean and fresh.

Step 1. Preparation

Before you begin, make sure that you have all of the necessary supplies on hand, including baking soda, a scrub brush and some water. You may also need to wear rubber gloves or protective clothing if there is any risk of splashing or staining yourself while doing the job on your own.

Step 2. Cleaning

Start by mixing one cup of baking soda with two cups of warm water in a large bowl or bucket. Stir until all of the baking soda has dissolved into the water completely, then add another two cups of water until your mixture is about half as thick as honey.

Now add this mixture to your bathtub and allow it to sit for about 20 minutes so that it can absorb any remaining stains from your fiberglass surface before scrubbing it off with a scrub brush or sponge until they are fully removed.

Vinegar and Borax

Vinegar and borax are both natural cleaners that can be used to tackle rust stains on a fiberglass tub. The combination of these two ingredients creates a chemical reaction that breaks down the rust stain.

The process for cleaning rust stains from your bathtub is simple: Clean the stain with vinegar, then scrub it away with borax.

First, clean the rust stain with full-strength white vinegar. Use a sponge or rag to apply the vinegar directly to the stained area. Let sit for five minutes, then wipe away with a damp cloth or sponge. 

Rinse thoroughly with warm water, then dry completely with a towel or use an air compressor to blow off excess moisture from the fiberglass surface.

Next, sprinkle borax over the stain and let sit for 10 minutes before scrubbing clean using a soft scrub brush. Rinse well under running water, then wipe dry with a towel or use an air compressor to blow off excess moisture from the fiberglass surface.

How you can Prevent Rust on your Fiberglass Tub

Rust Stains from Fiberglass

Fiberglass tubs are durable and easy to maintain. They do not require any special care or cleaning methods, but there are some things you can do to keep them looking their best.

Here are some tips to help you prevent rust on your fiberglass tub:

Keep it clean. Dirt and grime can cause stains on the surface of the bathtub. To prevent this, wipe up any spills immediately. Use a soft sponge with warm water to wipe down the surface, paying special attention to areas where soap scum builds up, such as around the faucets and drain.

A mild detergent in warm water instead of harsh cleaners such as bleach or ammonia-based cleaners that can discolor or damage fiberglass surfaces. Use a soft cloth or sponge with warm water to wipe down the surface thoroughly and rinse well with clean water afterward.

 If any residue remains after cleaning, use baking soda dissolved in warm water instead of regular household cleaners; this will help remove even hard-to-remove stains without damaging your fiberglass tub or other bathroom fixtures or finishes.

Keep it dry. Water left standing for long periods of time on fiberglass surfaces may cause condensation which can lead to mold growth inside your tub


There are two basic types of rust removers: acid-based and alkali-based. Both remove the rust, but they do so in different ways. The acid ones take a more direct approach, attacking the rust chemically and thus producing more immediate results. The alkaline ones work more slowly, but they attack any remaining stains as well. They will not stop new stains from forming, however, so you may need to reapply these products more often than the acid variety.