Abrasive blasting is a process of removing everything on the hull of a boat to bring it back to bare steel using an abrasive material forced out of a high-pressure nozzle under compressed air. This method removes paint and rust leaving a surface that provides a deep anchor for new coatings. At P&S Marine we use an airless spray system to apply an epoxy primer as well as an epoxy top coat on top of a blast primer to ensure a premium, quality finish. Hulls which have not been out of the water for a long time and as a result are in a poor condition, benefit from this process the most. After epoxy paint systems have been applied to properly prepared surfaces, paint manufactures generally suggest that a vessel will not need to come out of the water again for additional coatings for ten to fifteen years. At P&S Marine we provide a professional blasting and spraying service that we carry out ourselves using our own equipment.

P&S Marine - Grit Blasting: blasting swim

Blasting & The Weather

Although better, due to increases in paint and blast pot technology, the process of abrasive blasting is weather sensitive. The actual process of blasting can be carried out on moist days (i.e. fog and drizzle) due to our pot being constantly pressurised, however full on rain halts the process. A saturated surface is near impossible to blast and likewise, a wet blasted surface will begin to rust (ginger) and quickly becomes an unsuitable surface for new coatings.

Abrasive Blasting Finishes

Along with the weather, the time it takes to blast a hull depends, obviously, on its length but also on what condition the hull is in. Boats which haven’t been out of the water for a long time tend to be in worse condition and have more of a build-up of marine growth on them compared with boats that have had a regular maintenance schedule. The number of coatings and their composition also affects the speed of which they come off when being blasted. Finally, the mill-scale on the surface of the steel needs to be abraded (sa2) or removed altogether (sa2.5). Mill-scale is the film of impurities that hardens on the surface of steel during the manufacturing process and can often be the toughest thing to remove during blasting. Above the waterline being harder than underneath, presumably as being immersed in water softens it. Due to all these factors, the length of time it takes to blast a hull varies considerably.

P&S Marine - Grit Blasting: perfect SAE 2.5 finish
P&S Marine - Grit Blasting: perfect SAE 2.5 finish
P&S Marine - Grit Blasting: SAE 2 finish alongside un-blasted
P&S Marine - Grit Blasting: SAE 2 finish alongside un-blasted

Sections with a SAE 2.5 finish – ideal for new coatings

An unfinished section with a SAE 2 finish

P&S Marine - Grit Blasting: primed hull side

Epoxy Blast Primer & Aluminium Undercoat

After the vessel has been lifted out of the water, the hull allowed time to dry and the boat sheeted up, we aim to blast one side of a hull in a day at the very least – depending on how easy the above factors make it, we try to get both sides blasted on the first day. After we have blasted our intended amount in a day (and keeping an eye on the weather and amount of daylight left) we then apply the blast primer by brush and roller.  This ensures that the newly blasted surfaces are not left out to the atmosphere so as to ginger and provides the perfect surface for the top coats to be applied to. We continue this process until the entire hull (sides up to the top rubbing strake and baseplate) has been blasted and blast primer applied after which the aluminium undercoat is then applied with our airless spray system.

P&S Marine - Grit Blasting: half and half baseplate
P&S Marine - Grit Blasting: un-blasted hull side

Before

Top Coats

The final step in the process is applying the top coats. At P&S Marine we welcome you to do this yourself (DIY) or we can apply it for you using our airless spray system (P&S Blacking). Our spray system ensures the correct film thickness is applied for each coat (125 – 375 microns) and also provides a much better finish compared to using a roller and brush. If you’re applying it yourself we insist on you using the product we sell as it is compatible with the other products it will be painted onto. If we are spraying, we aim to apply one coat in a day, followed by the second coat on the second day, allow the manufactures recommended overcoating time in between which varies depending on temperature.

After the final top coat has had enough time to cure, and anodes fitted or replaced, the boat can then be put back in the water.

P&S Marine - Anodes: recommended configuration of anodes on the baseplate
P&S Marine - Grit Blasting: finished boat

After

If you would like to know more about abrasive blasting or are looking for an estimate please contact us

Abrasive Blasting & Painting Prices

For a better break down on prices please see our price list on the menu bar or contact us

Prices For Abrasive Blasting Only

Use this price if you intend on applying the epoxy top coat yourself. Includes application and material costs of blast primer and epoxy undercoat.

Abrasive Blasting Narrow-beam (up to 7ft)

£6002per ft (inc. VAT)
  • Baseplate and sides up to top rubbing strake

Abrasive Blasting Wide-beam (over 7 ft)

£6603per ft (inc. VAT)
  • Baseplate and sides up to top rubbing strake

Prices For Abrasive Blasting & Epoxy

The overall cost of blasting and application of epoxy top coat. Includes material costs.

Abrasive Blasting & Epoxy Narrow-beam (up to 7ft)

£9052per ft (inc. VAT)
  • Abrasive blasting and 2 coats of epoxy top coat

Abrasive Blasting & Epoxy Wide-beam (over 7 ft)

£10153per ft (inc. VAT)
  • Abrasive blasting and 2 coats of epoxy top coat