Getting a Boat's Gelcoat Back: Oxidation to Wax

A boat that has sat in the sun for a few seasons starts to look tired. The white hull goes dull, then chalky, and the color seems to drain out of it. That is oxidation, and it is one of the most common problems we see when boat owners in Northern NJ bring a boat to the shop. The good news is that it is usually fixable.

What oxidation actually is

A boat hull is coated in gelcoat, a hard but fairly thin outer layer. Sun, water and weather break down the surface of that layer over time. The top of it turns porous and chalky, and it stops reflecting light the way it used to. That is why an oxidized hull looks flat instead of glossy.

You can test it yourself. Rub a clean white cloth on the hull. If color comes off on the cloth, the gelcoat is oxidized. The more color, the further it has gone.

How we bring it back

The fix is to remove the dead outer layer and reach fresh gelcoat underneath. How aggressive we get depends on how far the oxidation has gone.

• Wash the hull thoroughly so no grit is on the surface.
• Wet sand where needed. Sandpaper is used with water, in progressively finer grits, to level the damaged surface evenly.
• Machine polish. Polishers bring the sanded surface back to a clear, deep gloss.
• Protect with a marine-grade protection, which seals the gelcoat and slows oxidation from setting back in.
• Clean and treat plastics and vinyl so the rest of the boat matches the hull.

Wet sanding is the step that takes skill. Gelcoat is only so thick, and sanding removes some of it. Too much in one spot and you cannot put it back. That is a good reason to leave the sandpaper to someone who does this regularly, rather than learning on your own hull.

The before and after photo on this page is a real hull from our shop. The difference between the before and the after is the difference between chalk and gloss.

What it costs

Oxidation removal and protection starts at $45 per foot. That covers the full restoration described above: wet sanding, machine polish, marine-grade protection, and the plastics and vinyl. Wet sanding on its own runs $30 to $45 per linear foot. These are starting prices, and the final figure depends on how far gone the gelcoat is.

For boats that do not need a restoration, we have maintenance options priced by the foot.

• Basic boat wash, from $20 per foot.
• Wash and wax, from $25 per foot.
• Polish and wax, from $35 per foot.

Which one does your boat need?

A simple way to decide. If the cloth test comes back clean and the hull is shiny, a wash, or a wash and wax, will keep it that way. If the hull is still fairly glossy but has lost some depth, polish and wax brings it back without sanding. If the cloth comes away colored and the finish looks chalky, you are in oxidation removal territory.

Most boat owners find that a restoration is a one-time heavy job, followed by regular wash and wax visits to keep the finish from slipping back. Waxing adds a protective layer on top of the gelcoat, and it is much cheaper to maintain a restored hull than to restore it again.

Where the boat lives makes a difference too. A boat kept under cover or out of direct sun between trips oxidizes more slowly than one left uncovered all season. Rinsing off after each outing and keeping a coat of wax on the hull also helps, because wax gives the sun and water something to wear down before they reach the gelcoat itself. None of that replaces a restoration once the chalk has set in, but it stretches the time between big jobs.

Jet skis too

We also detail personal watercraft. A detail wax on a jet ski starts at $79, and a full detail starts at $125. Our bay has held cruisers, a Stingray on its trailer, and a pair of jet skis in the shop window, so we are used to working around hulls, rails and tight spaces.

Get a number for your boat

Boats are priced by length and by condition, so the quickest way to a real figure is to show us the boat. Call (908) 813-1130, or bring it to 400 High Street in Hackettstown. You can read the full service list on the Marine Detailing page under Services, and the starting prices for everything else are on the Pricing page.