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Gelcoat Sanding and Polishing for Yachts
Factory Gelcoat Production and Maintenance for Boats and Yachts
Salt, water and wind all challenge marine surfaces. To get the perfect luster and shine of a gelcoat surface on a newly manufactured yacht or boat, the crucial component is the exterior layer of the gelcoat. For yachts, the gelcoat surfaces are made to be long-lasting, to be able to resist UV damage and rough conditions at sea, but they must be maintained for a long life. And a maintained gelcoat surface is not only about looks. You will also protect the yacht or boat from salt, filth, mold, and excessive moisture with a well kept gelcoat surface.
It is easy to condition a gelcoat finish with Mirka solutions. Use Mirka® Galaxy or Abralon® for machine sanding the surface, work with Polarshine to remove swirls and polish it, and finish the job by protecting the surface. You can find the perfect match for your polishing needs with this handy compound grade scale. We also offer complete finishing kits to make it even easier.
For a superb shine on yachts and boats
Sanding and Polishing Gelcoat Surfaces
2/8 - Step 1
Sanding
Start sanding with Mirka® Galaxy 240 grit together with Mirka® DEROS 650CV
in case of significant orange peel. Otherwise, start from 320 grit.
3/8 - Step 2
Continue sanding with Mirka® Galaxy 500 grit.
4/8 - Step 3
Continue by attaching the Mirka® Net Interface to the Mirka® DEROS 650CV. Sand with Galaxy 800 grit.
5/8 - Step 4
Finish the sanding with Mirka® Galaxy 1000 grit together with a Mirka® Net Interface.
Use 1200 grit on dark colours.
Clean the sanded area with a Micro Fiber cleaning cloth. The sanded area is ready to be polished.
6/8 - Step 1
Polishing
Start by fitting the Twisted Wool Pad to your polishing tool.
Apply Polarshine® 45 polishing compound onto the wool pad. Start polishing.
7/8 - Step 2
Light and dark colored surfaces
Fit a Waffle polishing foam pad and apply Polarshine® 12 onto the pad. Polish the surface.
8/8 - Step 3
Clean the polished area with a micro fiber cleaning cloth.
Process steps
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Steady grip. Less than 7 lbs. High flexibility.
Mirka® LEROS-S. Reach Closer.
The Mirka® LEROS-S features the well-known benefits of the LEROS, but in a shorter, easier to handle length. This makes LEROS-S perfect for sanding larger areas, such as yachts and boats, faster. The LEROS-S has two dedicated grip points for full control.
Thanks to its lightness, balance and easy maneuverability, the LEROS-S makes it possible to sand large areas faster and easier. The large sanding pad with its 5mm orbit works especially well in leveling filler.
It features a highly flexible sanding head to make sanding easier and more ergonomic. A better working position makes sanding more effortless and improves the end result as well as productivity.
Nautor's Swan, Finland
High-Quality Finish in Yacht Production
For Finnish yacht builder Nautor, a high-quality finish is about respecting the company’s roots and heritage, and it takes the best kind of power tools and abrasives to accomplish that. Benny Brännbacka from Nautor shares with us what it means to collaborate with Mirka, and how important client satisfaction is when building spectacular yachts with Mirka's solutions.
"Working with Mirka is very good, we are continuously collaborating."
Why Choose Mirka?
Save time and money – You can cut costs and reduce working hours
Why Choose Mirka?
Sand and polish safely without strain – Our tools and abrasives are ergonomic, efficient, and easy to use
Why Choose Mirka?
Improve the quality of work – The finish is excellent, with less effort
Save your health, time, and money
Sanding Without Dust
Do you get covered in dust when sanding? Try the benefits of Mirka's pioneering sanding solutions and see how a dust-free working environment can boost your business.
Benefits from dust-free sanding
Healthier working environment – Stop dust from getting into your lungs
Time-saving – No cleaning after sanding and clean abrasives cut better
Money-saving – No clogging lets you sand longer with the same abrasive
High-quality finish – Thanks to a finer scratch pattern
Corded 150 mm polisher
POLAROS® RP 600
The POLAROS® RP 600 is a professional 150 mm rotary polisher, powered by a quiet 750 W brushless motor.
POLAROS's low-profile, lightweight design offers superb control, making it ideal for detailing, bodywork, marine, wood, and glass applications.
The unique, patent-pending Ramp Up and Ramp Down functions add to the POLAROS's usability by ensuring smooth starts without splatter and protecting the polisher and the surface from excessive pressure.
Harness the power of modern polishing technology in every finish with POLAROS.
A better choice for you and the environment
Water-Based Polishes
All polishes that Mirka produces are water-based and produced in Finland. There are many benefits of choosing a water-based polishing compound.
- Effective permanent removal of scratches - Water-based compounds remove scratches permanently. Solvent-based compounds can lose gloss after cleaning the surface with a degreaser and in some cases, they may only temporarily hide the scratches.
- Safer for the operator - No hazardous chemicals
- Sustainable - Water-based polishes are better for the environment and do not contain benzene.
Solvent-based polishes may be effective in the short run, but they are more damaging and harmful.
Kim Rönnholm
Portfolio Manager, Mirka
You Might Be Interested In
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Please get in touch and our expert support team will answer your questions.
How to Restore Gelcoat on a Boat
Over time, your boat’s gelcoat can lose its shine and start looking dull. Sun, saltwater, and regular use slowly wear away the surface, leaving it faded, chalky, or rough to the touch.
If you ignore these changes, the damage can become harder and more costly to fix. Restoring your gelcoat properly brings back its smooth, glossy finish and protects it from further wear.
In this article, you’ll learn how to restore your boat’s gelcoat step by step, what tools you’ll need, and how to keep it looking its best.
Signs Your Boat’s Gelcoat Needs Restoration
Your boat’s gelcoat is its first layer of protection and the surface everyone sees. Over time, sun, saltwater, and daily use slowly wear it down. If you know what to look for, you can restore it before the damage gets worse.
One of the first signs is a faded or chalky appearance. If the hull looks pale or the color seems uneven, the gelcoat surface is wearing away. You might notice a powdery feel when you touch it. Run your hand along the side of your boat, and if you see a white powder on your fingers, it means the gelcoat is breaking down.
Another sign is a loss of shine and color depth. Fresh gelcoat has a deep, glossy look that reflects light evenly. When this shine fades, it often means UV rays have damaged the top layer.
On a sunny day, stand a few feet away and compare the side that gets the most sun with a shaded side. You will often see the exposed side looking duller.
Oxidation is another clear indicator. It leaves a fine powder on the surface, making it rough and harder to clean.
Dirt and stains stick more easily, so rinsing no longer restores the bright, clean look. If your boat still looks dull after a wash, it is a sign the gelcoat needs attention before the damage becomes harder to fix.
Tools and Materials Needed for Gelcoat Restoration
Mirka® Galaxy Abrasives with Net Interface
When you are sanding a boat’s hull, you need an abrasive that cuts efficiently without wearing out too soon. Mirka® Galaxy is self-sharpening, which means it keeps its cutting ability even after long use.
The net interface improves dust extraction, so you will not be working in a cloud of particles. This helps you see exactly what you are sanding and keeps your work area cleaner. This is important when you are on a marina dock or in a tight boathouse space.
Benefits for your project:
- Maintains a consistent cut for faster sanding
- Reduces clogging and extends abrasive life
- Keeps dust away from freshly prepared surfaces
For example, when removing oxidation from the starboard side of your boat, you can start with a coarser Galaxy grit to cut through the chalky layer, then switch to finer grits for a smooth, polish-ready finish.
Mirka® DEROS Electric Random Orbital Sander
Large hull areas can be tiring to sand by hand. The DEROS 650CV is lightweight and balanced, making it easier to handle over long periods.
Its 5 mm orbit ensures an even and swirl-free finish, which is critical for gelcoat surfaces. When paired with Galaxy abrasives, you will remove oxidation and surface scratches faster, meaning you can move on to polishing sooner.
Why it matters for your gelcoat restoration:
- Covers more surface area in less time
- Minimizes operator fatigue on long projects
- Works seamlessly with dust extraction for cleaner results
Imagine tackling both sides of your 30-foot boat in one weekend. The DEROS makes that possible without compromising quality.
Polarshine® Marine Polishing Compounds
After sanding, your gelcoat needs polishing to restore its gloss. Polarshine compounds are water-based and designed specifically for marine use, so they cut effectively without leaving harmful residues.
The Heavy Cut formula removes deeper oxidation and sanding marks, while the Fine Compound delivers a high gloss finish that lasts in sun and saltwater conditions.
Key advantages for your boat:
- Marine-specific performance for gelcoat
- Safe for you and the environment
- Long-lasting shine in harsh UV and salt exposure
For instance, after sanding your deck, applying Polarshine Fine will bring out a mirror-like reflection you can see from the dock.
Mirka Marine Polishing Kit
This kit is a complete solution. It includes Galaxy abrasives, Polarshine compounds, twisted wool pads, and microfiber cloths.
Everything works together, so you will not have mismatched results from using mixed brands. It is ideal if you want to start your gelcoat restoration with all the right components in hand.
Why this kit works for boat owners:
- One purchase for the full restoration process
- Consistent results from matched products
- Saves time sourcing separate tools and materials
If your boat’s hull has not been touched in years, having the kit means you can go from sanding to polishing in one workflow without waiting for missing items.
Step-by-Step Guide to Restoring Gelcoat on a Boat
Step 1: Prepare the Boat for Gelcoat Restoration
Start by giving your boat a thorough wash from bow to stern. Use marine-grade boat soap and plenty of fresh water to remove salt, grime, and organic buildup. Pay attention to waterlines and under fittings where residue often hides.
Inspect the gelcoat closely in bright light. Look for oxidation, scratches, or faded areas. This assessment will guide your sanding and polishing approach.
Before you begin, tape off metal fittings, rubber seals, and trim. This prevents accidental scratching during sanding and polishing. If your boat is in a marina, secure it well so movement doesn’t affect your work.
Step 2: Remove Oxidation from the Gelcoat
Oxidation is the chalky, powdery layer that dulls your gelcoat. It forms when UV rays and oxygen break down the surface. Severe oxidation can make the gelcoat porous, trapping dirt and moisture.
For heavy oxidation, start with Mirka Galaxy abrasives in a coarser grit and work your way to finer grits. Pair them with the Mirka DEROS electric random orbital sander for even coverage and dust-free sanding. This saves time and keeps the surface clean.
In tight areas, switch to smaller sanding pads or hand sanding with Mirka net abrasives. For example, around cleats or under the rub rail, a smaller pad will let you match the surrounding finish without over-sanding.
Step 3: Polish the Gelcoat to Restore Shine
Once the oxidation is gone, your gelcoat surface will look smooth but dull. Polishing removes fine sanding marks and brings back the gloss.
Use Mirka Polarshine Heavy Cut if you’ve removed heavy oxidation. Work in small sections, keeping your polisher moving to avoid heat spots. Once the surface looks uniform, follow with Polarshine Fine to deepen the shine.
Think of this like buffing a mirror. Each pass refines the surface until it reflects light evenly. On sunny days, check your progress from different angles to ensure there are no hazy spots.
Step 4: Apply Protective Wax Coatings
Polishing exposes a clean, smooth gelcoat, but without protection, oxidation will return quickly. Wax seals the surface, blocking UV rays and salt damage.
Paste wax provides the most durable barrier. Apply it by hand for even coverage. After the first coat cures, add a second coat for maximum protection. Yes, it’s more work, but it pays off in longer-lasting results.
Liquid wax is easier to apply for future touch-ups. For example, you can reapply it every few weeks during the season to maintain gloss between major restorations.
Step 5: Maintain the Restored Gelcoat
Regular maintenance is the only way to keep your gelcoat looking new. Rinse your boat with fresh water after every trip, especially if you’ve been in saltwater.
Schedule a light polish with Polarshine Fine every few months, depending on exposure. In high UV regions, you may need it more often.
Keep a microfiber cloth and quick marine spray detailer onboard. This lets you wipe away bird droppings or stains before they etch into the surface. Small, consistent care prevents another major restoration for years.
Common Challenges in Gelcoat Restoration
Handling Severe Oxidation on Older Boats
Older boats often have thick, stubborn oxidation. Years of sun and saltwater exposure make the gelcoat chalky and rough.
This isn’t just a cosmetic problem; if you leave it untreated, it can weaken the surface and make restoration harder later.
Solution: Use a strong sanding and polishing process to remove the damaged layer. Mirka’s Galaxy abrasives cut through heavy oxidation quickly, and when you pair them with the DEROS sander, you’ll get an even, controlled surface ready for polishing.
Working in Tight or Hard-to-Reach Areas
Sections around cleats, rails, and under the rub rail can be hard to sand evenly. If you skip these spots, the finish will look uneven, and oxidation can return faster.
Solution: For these areas, use smaller sanding pads or hand sanding with Mirka’s net abrasives. The open mesh design keeps dust out of your way, so you can see exactly what you’re working on, even in tight spaces.
Choosing the Right Compound for the Level of Oxidation
Using a compound that’s too strong can remove more gelcoat than necessary. Using one that’s too light won’t remove enough oxidation. Both mistakes cost you time and reduce surface quality.
Solution: Test a small section first. For heavy oxidation, start with Polarshine Heavy Cut, then follow with Polarshine Fine for a high-gloss finish. For lighter oxidation, skip the heavy cut and use Polarshine Fine directly.
Preventing Swirl Marks and Uneven Polishing
Swirl marks happen when polishing pads or sanders move unevenly, or when you use the wrong grit sequence. They make your gelcoat look dull, even after polishing.
Solution: Keep a consistent sanding pattern and work through grits in the right order. Using the DEROS with Galaxy abrasives ensures even sanding, while Polarshine compounds and proper wool or foam pads help you finish without swirls.
Conclusion
Restoring your boat’s gelcoat is an investment in both appearance and protection. By understanding the signs of wear, following the correct restoration steps, and committing to regular maintenance, you can extend the life of your gelcoat and keep your boat looking its best.
The process takes time and attention to detail, but the reward is a smooth, glossy finish that stands up to the elements and makes every trip on the water more enjoyable.
Best Gelcoat Restoration Kits for Boat
If you own a boat, you know the frustration of seeing the gelcoat lose its shine. Sun, saltwater, and constant exposure leave the surface dull, chalky, and worn. It not only looks bad but also makes cleaning harder and reduces protection for your fiberglass.
This is where a gelcoat restoration kit becomes essential. With the right kit, you can remove oxidation, restore color, and bring back a durable gloss to your boat’s surface. Instead of patchwork fixes, a complete kit gives you the tools to handle sanding, polishing, and finishing in one process.
In this article, you will learn what gelcoat restoration is, why your boat needs it, what to look for in a kit, and the best options available. By the end, you’ll know exactly which solution can help you protect and restore your boat’s appearance.
What is Gelcoat Restoration?
Gelcoat restoration is the process of repairing and renewing the protective outer layer applied to a fiberglass boat. This layer provides both a glossy finish and a barrier against UV rays, saltwater, and mechanical wear.
Over time, gelcoat becomes oxidized, chalky, or scratched due to constant exposure to harsh marine environments. Restoration removes oxidation, levels out imperfections, and polishes the surface back to a smooth and durable state.
The process often involves multiple sanding steps with marine abrasives, followed by polishing compounds that refine the surface.
This ensures the gelcoat not only looks new but also maintains structural integrity and protection for the fiberglass underneath.
Why Boats Need Gelcoat Restoration
Boats face continuous exposure to sunlight, saltwater spray, and abrasive docking conditions. These factors break down gelcoat, leading to dullness, surface pitting, and loss of protective qualities.
If gelcoat is not restored, damage can extend deeper into the fiberglass, leading to costly repairs and reduced vessel lifespan. Early intervention with a proper restoration process prevents long-term structural issues.
A restored gelcoat also improves the efficiency of cleaning and maintenance. Smooth, polished surfaces resist algae, biofouling, and salt deposits, making routine washing faster and less labor-intensive.
For owners considering resale, a well-maintained gelcoat significantly improves the visual appeal and market value of the boat. Shiny, defect-free surfaces are a strong indicator of professional care and overall vessel condition.
What to Look for in a Gelcoat Restoration Kit
A proper gelcoat restoration kit should cover the full process: surface sanding, scratch removal, polishing, and finishing. Kits that include abrasives, compounds, pads, and cloths allow you to complete each step without sourcing additional items.
Look for abrasives with controlled cutting power; mesh or self-sharpening discs are ideal for removing oxidation without clogging. Water-based polishing compounds are safer and produce a lasting gloss compared to solvent-heavy alternatives.
Pads and backing accessories should be designed for marine use, allowing even work on large hulls, tight curves, and vertical sides. Microfiber cloths are essential for residue removal, final finishing, and quick touch-ups on windows, hatches, or railings.
Consider the ergonomics and efficiency of the kit as well. Lightweight pads and dust-free sanding solutions reduce strain on your crew and shorten total project time, delivering measurable cost savings in large-scale restoration projects.
Best Gelcoat Restoration Kits for Boats
1. Marine Polishing Kit 6" Galaxy
This Marine Polishing Kit 6" Galaxy kit is built for restoring gloss and protecting your boat’s gelcoat surfaces. It includes Galaxy abrasives, Polarshine® polishing compounds, twisted wool pads, microfiber cloths, and a backing pad.
- Galaxy abrasives: Self-sharpening discs that cut fast without clogging, making them effective for removing oxidation and dull spots on large boat surfaces.
- Polarshine® compounds: Water-based compounds that remove fine scratches and restore depth of color to faded gelcoat.
- Wool pads and microfiber cloths: Pads spread the compound evenly, while microfiber cloths remove residue and leave a swirl-free surface.
- Backing pad: Holds the abrasives steady and ensures an even cut across curved hulls and decks.
When you use this kit, you can sand away chalky oxidation on the hull, polish out light docking scratches, and bring back the glossy reflection on your boat sides.
The microfiber cloths are not just for finishing—they are handy for wiping salt spray from windshields or cleaning residue around fittings after polishing.
With everything included, you save time moving between sanding, polishing, and finishing, while getting a professional-grade result.
2. Marine Commissioning Kit 6" Abranet Ace HD
This Marine Commissioning Kit 6" Abranet Ace HD is designed for heavy-duty restoration work on gelcoat before polishing. It contains Abranet® Ace HD abrasives, Polarshine® compounds, foam and wool pads, and a microfiber cloth.
- Abranet® Ace HD abrasives: Built for aggressive sanding, they remove tough oxidation, sanding marks from repairs, and weather damage on gelcoat.
- Polarshine® compounds: Smooth and protect the surface after sanding, bringing out a consistent finish across large marine areas.
- Foam and wool pads: Foam pads are ideal for controlled polishing on smaller curves, while wool pads handle large flat surfaces quickly.
- Microfiber cloth: Cleans away polishing dust and compound residue, leaving a clear finish ready for waxing or sealing.
You’ll find this kit useful if you need to level out scratches from trailer rollers, sand down repaired patches, or restore areas that have been neglected under covers.
The Abranet Ace HD abrasives give you the power to cut through stubborn oxidation where lighter abrasives fail.
The microfiber cloth can also be used between stages to quickly wipe down hatches, rails, or other spots where polishing residue builds up.
This makes the kit practical for the real work you face during full gelcoat restoration.
3. TotalBoat Marine Gelcoat
TotalBoat offers gelcoat repair and restoration products commonly used for smaller boat projects. Their kits are designed for patching and refinishing areas affected by scratches, chips, or UV fading.
These solutions are practical for do-it-yourself boat owners who want a cost-effective way to address localized gelcoat wear.
While useful for minor work, they may require additional tools and materials for a complete restoration.
4. Meguiar’s Gelcoat Restoration Kit
Meguiar’s provides marine surface care kits that focus on cleaning, restoring, and protecting boat finishes.
Their products typically include cleaners, compounds, and waxes aimed at bringing back shine on faded gelcoat.
These kits are suitable for light to medium oxidation and for maintaining the boat’s appearance between major restorations. They are easy to use but are more limited in scope compared to full professional systems.
Why Choose Mirka Gelcoat Restoration Kits
Advanced Dust-Free Sanding Technology
Mirka is the inventor of dust-free sanding. With Abranet® net abrasives and high-performance dust extractors, you can restore your boat’s gelcoat without filling the air and work area with harmful dust.
This means faster cleanup, safer conditions for your crew, and a surface that is ready for polishing right away.
Complete All-in-One Marine Solutions
Mirka kits combine abrasives, polishing compounds, backing pads, and accessories in one package.
This gives you everything needed for gelcoat restoration without sourcing products from multiple suppliers. It simplifies the workflow and ensures compatibility between each product in the process.
Proven Time and Cost Savings in Marine Projects
Field tests confirm Mirka’s “Sand Better, Polish Less” process. Spending slightly more time sanding reduces polishing time by up to 30 percent.
For yacht projects, this can save days of labor and thousands of dollars in costs. The process delivers consistent results across large marine surfaces.
Ergonomic and Worker-Friendly Tools
Tools such as Mirka® LEROS and LEROS-S are lightweight and reduce operator strain during long restoration tasks.
Their flexible heads and dual-grip designs improve control on large boat surfaces and in confined areas. This ergonomic approach helps your team work longer with less fatigue.
Sustainable and Eco-Friendly Approach
Mirka leads sustainability efforts in the abrasives industry. The company is a founding member of the SEAM program in Europe, which sets standards for energy savings, waste reduction, and worker safety.
Products like Polarshine® polishing compounds are water-based and free from hazardous solvents, reducing environmental impact while protecting your boat’s surface.