How To Remove Rust Stains From Fiberglass Gelcoat?

Fiberglass is often used in boats for being stronger than wood. Gelcoat is used to make fiberglass smoother and shinier. Unfortunately, they aren’t rust-proof and can easily get rust stains. But luckily, this problem is pretty easy to fix. 

So, what’s the best way of removing rust stains from fiberglass gelcoat? 

Rust stains are easily spread on fiberglass but they’re also easy to remove. First, you’ll need to make a baking soda paste or a white vinegar solution. Then you’ve to apply the paste/solution to the stained area. Wait for 2-3 hours or a night then use a sponge to wipe the paste off. 

Anyways, that was a short preview of the whole procedure. Keep reading if you want to know the process step by step with more details. 

We will come back to this further down the article but here’s a link if you want to see more about the special Clean Bees Bristol.

So, let’s head right in- 

Removing Rust Stains From Fiberglass Gelcoat

What Causes the Rust Stain On Fiberglass?

Most boats have steel hardware. Although they are stainless, they can catch rust stains after a lot of usage. Stainless steels are also very weak to corrosion as well. 

Since most hardware is attached, the corrosion can often spread to the fiberglass. For example, boat fasteners are always in contact with water and spread rust.

There’s another reason behind fiberglass with Gelcoat finishing getting rust stains. This is called galvanic corrosion. It occurs when there are two different metals close to electrolytes. 

That’s why it’s always advised to avoid keeping the metals close to each other. 

How To Remove Rust Stains On Fiberglass Gelcoat?

Generally, any non-abrasive or mild-abrasive rust stain remover works just fine. However, they are quite expensive and sometimes may not be available near you. 

That’s why we’ve used a cheap and affordable method that anybody can use. Here’s what you’ll need to start the procedure on how to remove rust stains from fiberglass boats- 

• Baking Soda.
• White Vinegar.
• Spray Bottle.
• Non-abrasive Sponge.
• Nylon Brush.
• Power Polisher (optional). 

Now, get these materials as soon as you can and get started on how to remove yellow stains from fiberglass boats! 

Step 1: Remove the Steel Hardware & Wash the Fiberglass

First, you’ve to uninstall all the steel hardware that you have in your boat. Since rust stains start from these areas, it’s best to remove them. 

This also allows you to do a full inspection of a boat. Even a small rust stain can spread rapidly. That’s why you can’t afford to leave one behind.

Once you’ve removed all the hardware, it’s time to give the boat a good wash. If you don’t have too many rust stains you can skip this step.

Get some soap and water first. Then use a non-abrasive sponge to wash the boat. This will dampen most of the rust stains. 

Step 2: Prepare the Baking Soda Paste Or Vinegar Solution

Baking soda is one of the most common household items. It’s also accessible to anyone. Even if you don’t have it with you, you can just borrow some from your neighbor! 

First, take a small bowl and add ½ cup of baking soda. Then pour a small amount of water and mix the solution. 

Remember that the paste must not be too dry or too watery. So, start with a low amount of water. Then gradually add a little bit more to get the right amount. You can also mix some vinegar into the baking soda paste. 

On the other hand, you can also use a vinegar solution. White vinegar is the most effective but you can use regular vinegar as well. 

Take a spray bottle and fill ¼ or ⅕ of the bottle with vinegar. When you’ve poured the right amount, fill the rest with cold water. 

Step 3: Apply the Mixture On The Stained Area

It’s time to get rid of that stinky rust stain once and for all. To apply the baking soda paste, you’ve to get a nylon brush. 

Take a good chunk of that paste and apply it to the stain. Make sure no spot is left overlooked. If you’re using vinegar solution, spray all over the stained area. 

Generally, letting it sit for 2-3 hours does the job. However, if it’s a strong stain, you may want to let it sit for a whole night. 

Step 4: Wash the Fiberglass Again

Now, you’ve to remove the paste or solution that you applied. Use a non-abrasive sponge to get the stains out. 

You can also apply some vinegar to the paste and then wipe the stain off. But water is enough in most cases. 

Give the stained areas a good wash with water. Check if there are any more stains left or not. Simply repeat the process in case you spot any.

Finally, if you think the Gelcoat looks dull, you can apply some power polisher. It will instantly bring the gloss back. 

However, this may seem like a lengthy process to you. In that case, a rust stain remover will save you a lot of trouble. 

Our recommended removal of rust from a fiberglass boat

1. Best Rust Stain Remover For Fiberglass Boats: STAR BRITE Rust Stain Remover.
2. Best Rust Remover for Boats: Rust Stain Remover Spray.

Related Questions

Question: What removes rust stains from fiberglass?

Answer: Any ready-to-clean rust removers work on fiberglass due to being non-abrasive. However, you can use baking soda, white vinegar, and in some cases, an acetone mixture. 

Question: Is vinegar safe on fiberglass?

Answer: White vinegar or just regular vinegar are very good rust removers. They are also non-abrasive and don’t damage fiberglass at all. So, it’s a very good inexpensive alternative to rust stain removers. 

Question: Is CLR a better stain remover than vinegar?

Answer: The CLR is always better than vinegar due to having a lower pH value. The concentration of acid is also denser. That’s why the CLR is far better in the case of removing stains than vinegar. It’s about 15x-20x more effective than vinegar. 

Here is a helpful video on how to remove rust stains from fiberglass shower.

In Conclusion

Anyways, that was everything we could gather and explain on removing rust stains from fiberglass gelcoat. Hopefully, that was enough to satisfy your curiosity. 

Finally, best of luck with your boat!