Canal Boat Grit Blasting & Epoxy Paint Systems

Canal Boat Grit Blasting & Epoxy Paint Systems 2018-07-15T06:04:38+00:00

Grit blasting is the process of removing everything on a boats hull 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 airless spray a 2-pack epoxy primer as well as a 2-pack epoxy top coat 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 the most from this process. After 2-pack 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 6 years. This is generally double the amount of time for bitumen products thus having 2-pack paint systems applied to a boats hull effectively cut it’s maintenance schedule in half. At P&S Marine we provide a professional grit blasting and spray painting service that we carry out ourselves using our own equipment.

P&S Marine - Grit Blasting: blasting swim

Grit Blasting & The Weather

Although better, due to increases in paint and blast pot technology, the process of grit blasting is still weather sensitive. The actual process of grit blasting can be carried out on moist days (i.e. fog and drizzle) due to our pot being constantly pressurised and the 2-pack primer we use can be applied onto a damp surface, 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.

Grit Blasting Finishes

Along with the weather, the time it takes to grit blast a hull depends, obviously, on it’s 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 effects the speed of which they come off when being blasted. Finally the mill-scale on the steels surface needs to be abraded (SA 2) or if weak removed all together (SA 2.5). 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 grit 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 grit 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

2-pack Epoxy Primer

After the vessel has been lifted out of the water and the hull allowed time to dry, we aim to grit 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 day light left) we then apply a 2-pack epoxy primer using our airless spray system. This ensures that the newly grit blasted surfaces are not left out to atmosphere so as to ginger and provides the perfect surface for the top coat 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 2-pack epoxy primer applied.

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

Before

2-pack Top Coat

The final step in the process is applying the top coat. 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 (150 microns) and also provides a much better finish compared to using a hand roller. If your applying it yourself we insist on you using the product we sell as it is compatible with the 2-pack primer it will be painted on to and it is also a product we have tried and tested and can vouch for. 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.

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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 grit blasting or are looking for an estimate please contact us

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Grit Blasting & Painting Prices

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

Prices For Grit Blasting Only

Use this price if you intend on applying the 2-pack top coat yourself. Includes application and material costs of 2-pack primer.

Grit Blasting Narrow Beam (up to 7ft)

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

Grit Blasting Wide Beam (over 7 ft)

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

Prices For Grit Blasting & 2-pack Epoxy

Overall cost of blasting and application of 2-pack top coat. Includes material costs.

Grit Blasting & 2-pack Narrow Beam (up to 7ft)

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

Grit Blasting & 2-pack Wide Beam (over 7 ft)

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