Osmosis Treatment
Osmosis Treatment From The Experts
Osmosis Treatment
Thank you for considering using Dickies to treat your vessel for Osmosis. Dickies have been involved in the treatment of osmosis for more than 15 years, so we have a huge amount of experience in the field. In order that you understand the process and the various stages that take place, we have produced this guide. The reasons for boats developing osmosis can be quite varied and it is not proposed to discuss that matter here. There are many good sources of information where the causes of osmosis are explained. Our intention is to explain how we intend to treat osmosis and what you might expect to encounter.The stages taken for the whole osmosis treatment are as follows.
Call for a quote tel 01248 363400 or email :info@dickies.co.uk
The guide price given to you is comprehensive. Your vessel is lifted out at Bangor using our 30 Ton mobile boat hoist. Normally when the boat first comes out of the water, any blistering on the hull is at its most visible. While the hull is still wet the size and extent of the blistering is more apparent. Once the hull is dry osmotic blisters will be more difficult to spot.
The boat is taken to an area in the yard used for peeling and blasting the boats. The gel planner will take off the gel coat and a small amount of laminate. From experience it is clear that until the vessel is peeled and the underlying laminate exposed it is not possible to confirm what will be the most appropriate treatment for the boat.
It is also the time when previously unseen repairs become visible. Poorly carried out repairs can themselves be a source of high moisture content. If such repairs are discovered we would want to carry out remedial work for which we would charge according to the size of repair.
The laminate itself will need to be examined. Laminate which has poor resin saturation, will be visible and white in colour. Some manufacturers of boats have used pigmented (coloured) resins at certain layers of the build. Both these conditions will give rise to difficulty when trying to dry the boat out and remove the moisture from the hull.
In the case of poorly wetted glass matt and poorly bonded matting, it is likely that a second peel will be needed. This is to remove a potential source of material in which the osmosis process could start again. If this is the case an additional charge will be made both for the removal of the matting by gel peeling and also for applying a layer of laminate and resin.
Similarly pigmented lay ups are the source of problems and will need to be removed. This will be subject to additional charge as above.
Once sufficient layers have been removed a final grit blast takes place to open up any remaining small voids. We will now take readings at regular locations over the hull to establish a record of the drying out process. These first readings will allow us to see how wet the hull is and what we will need to do to dry the hull out.
It may seem peculiar but hot washing the vessel will be the next step. This is done to remove the glycols from the hull. Glycols are one of the contributory factors for osmosis taking place. This chemical is hygroscopic, that is it attracts water to itself. Therefore unless this chemical is removed it will draw water back to itself and the whole osmotic process could start again. So hot washes are essential and if effective will reduce the moisture content of the hull. This will be shown when the next set of readings are taken. However if the moisture content of the hull remains high, despite the hot wash process, then this is a clear indication that glycols are still present within the hull and that the hot washes have not been able to remove these chemicals. Similarly, the use of the Tramex and Sovereign moisture meters will also confirm that the moisture content is deep seated and that despite best practice it is likely that it will not be possible to bring these levels down. Given this situation, in consultation with the owner the decision will be taken to coat the hull with the epoxy system but no guarantee will be offered against the re-occurrence of Osmosis.
Dickies do have and use the Hot Vacs system to finally dry the boat but it must be stated that the Hot Vacs system is not a miracle cure and may not be able to draw deep seated glycols out.
The vessel will be moved into the shed and prepared for the epoxy treatment. The hull will have the hot vacs system applied to remove as much moisture as possible. Readings will be taken a full day after the pads have been removed and the readings checked. Once the readings are consistently at 5 and below on the Sovereign meter, it is considered the hull is ready for treatment.
The hull is given a coat of West Epoxy resin followed by a layer of filler (West resin and microlight). The hull is sanded the following day to give the vessel back its shape. A further 6 coats of West Epoxy resin are then applied. This is followed by a primer coat, which acts as a bond between the epoxy and antifouling. Finally two coats of antifouling finish the process off and the boat can be removed from the shed and prepared for launching.
The critical points to note are that a poorly laid up hull or a pigmented lay up will mean a further peel of the vessel and the application of a layer of laminate. This will be an additional cost.
If despite best practice, the moisture levels in the hull cannot be brought down to 5 or less on the Sovereign moisture meter, no guarantee against future occurrence of osmosis will be given. We do of course guarantee our work against defect as you would expect.
It is also our opinion that infra red heating of hulls has the effect or driving moisture into the laminate and the heaters should not be used to “dry out “ a hull, they should only be used to provide a dry warm environment. Similarly dehumidifiers will help in reducing surface moisture content and may also help in reducing damp atmospheres inside the boats themselves. Neither will reduce moisture held deep within a hull.
Call for a quote tel 01248 363400 or email :info@dickies.co.uk
