Removing Oil Stains From Gelcoat

When brand-new, the finish of a Gelcoat surface is exceptionally smooth, almost mirror-like.

When it ages, it gets porous, making it easier to discolor, appear worse, and become more challenging to clean.

Oil and other exhaust marks may manifest themselves on the surface. Is removing oil stains from Gelcoat possible?

Let’s dive into this post to get the answer!

Removing Oil Stains From Gelcoat: Solutions

The coating applied to perfectly polished mildew at the start of the fiberglass composite procedure is called Gelcoat.

The surface is outstandingly mirror-like, smooth, and aesthetically appealing on new watercraft.

Gelcoat gets permeable over time, and oil stains may appear on its surface. Luckily, you can restore it if it isn’t entirely worn through. 

Oil stains might develop on the gel coat’s wax surface but can be removed with the proper cleaning. 

Some elbow grease may be essential if the marks are deeper. Use harsher cleansers in place of 3 M’s boat soap to thoroughly clean and check the surface.

After cleaning, let the surface air dry before checking for dents, cracks, crazing, and other issues that should be fixed.

Before polishing the Gelcoat and recovering its brilliance, correct these defects.

Use a clean towel on the affected Gelcoat region to dab fibreglass cleaning solution.

Soot is deposited on the hull, which is why there are black or grey stains.

It may occur when diesel fumes from the wet exhaust system combine with salt water.

Either let those gasses out or use a dry exhaust system. The soot settles on the boat when you directly release it into the air.

The one-step liquid treatments, which consist of wax and polish or compound, simultaneously remove oil and safeguard the Gelcoat.

Wait 10 to 15 minutes. If the oil stains are only resting on the Gel Coat’s surface, they will start to come off; rinse and look at the result.

Repeat if the spots start to fade. Otherwise, something more potent should be necessary, such as a higher abrasive compound and a polisher.

The wax may be essential to recovering the glossy surface in that situation. The gel covering is partially lost every time you apply compound chemicals.

For this reason, utilize the least harsh product possible to complete the task with caution.

removing oil stains from gelcoat

Extra Tips On Maintaining The Gelcoat Finish For Your Boat

If you want to maintain your boat to have a smooth Gelcoat surface, follow these tips below:

Tip 1:

The easiest solution to reduce Gelcoat stains is to cover and preserve its surface with a high-quality polish or wax.

Afterwards, proceed with routine washdowns with mild boat soap to maintain this protection.

Tip 2:

Depending on the kind of marks you want to get rid of, you should choose a suitable stain remover.

Gelcoat stains come in two varieties: organic and mineral.

Plant stuff, bird droppings, and spilled beverages and food can all leave behind organic stains, which are the staining that is still visible after cleanup.

Rust stains are a type of mineral stain that typically appear at chainplate covers, exhaust ports, and stanchion bases.

Other stains are waterline marks and black spots brought on by minerals seeping into the water as it travels down the boat and through the scuppers.

There are several different Gelcoat stain removers. Each type is designed to get rid of a particular kind of spot.

Stain removal aims to get rid of the mark without harming the gel coat structure.

Avoid using harsh cleaners and abrasives such as sandpaper or heavy rubbing compounds.

Tip 3:

Washing the dirty areas using detergent and water will assist in removing Gelcoat water-soluble stains.

Nevertheless, mineral stains aren’t water-soluble, so trying to do so will be ineffective. Mineral stains need cleaning agents designed particularly for them.

Tip 4:

A more active strategy is necessary for dealing with stubborn waterline stains, calcium, and scrum development found during haulout.

It’s best to apply a potent acid formulation like Mary Kate’s On & Off Hull/Bottom Cleaner. 

Tip 5:

Spend some time giving the gel coat a protective wax layer after removing the spots.

It will establish a shield between staining substances and the gel coat’s pores, making it much simpler to clean up subsequent stains.

Tip 6:

Before rubbing off the Gelcoat and bringing back its gloss, look for dents, scratches, splits, and cracks and repair them.

Tip 7:

Depending on how much oxidation has built up, polishing, compounding, or waxing may be done with one or two steps.

Use slight pressure while keeping the equipment moving when utilizing a power buffer.

Tip 8: 

Before choosing a solution, it’s crucial to be aware that polish or rubbing chemicals employ abrasives to remove the uneven surface of the porous Gelcoat and bring back the shine.

The gel covering is partially lost every time you apply these products. Therefore, it’s best to consider the least harsh product possible.

removing oil stains from gelcoat

Can You Use Household Cleaners For Your Boat? 

The short answer is yes! However, it would be best if you thought about the effects of applying harsh or inappropriate chemicals to your boat’s delicate and specific areas.

If you don’t have specialized products for boat cleaning, here are some household cleaners to apply:

Dish Soap

These very caustic soaps, made to remove difficult stains and oil, will swiftly remove your wax.

Without wax, your watercraft will oxidize due to the sun’s Ultraviolet radiation, and the dishwashing will start eroding the Gelcoat.

You can still use dish soap, but it is preferable to use a boat-specific soap. Additionally, it is biodegradable while cleaning your vessel without removing the wax.


The bilge, difficult spots, and other unpleasant places of your vessel are just begging to be cleaned with bleach.

However, this substance may corrode the fittings, fade the paint, dull the Gelcoat within a few treatments, and affect the vinyl color.

You should be careful when selecting the safest product for your boat. 

Soft Scrub

In addition to removing stains, this product contains an incredibly abrasive grain that may quickly turn bright color and Gelcoat into a dreary haze.

It’s also ideal for restoring the dull spots around your watercraft resulting from inappropriate previous chemical applications.

The Bottom Line

In short, removing oil stains from Gelcoat is not challenging if you find the appropriate cleaning solutions and apply the correct method. 

It’s best to remove the oil stains on your boat once you’ve detected them to maintain a glossy and smooth surface. 

If you have further concerns, please comment below. Thanks for reading, and see you in the next post!

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