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3.1. Repair of solvent or amine blush blisters.
Repair of recurring "osmosis" is a delicate task and demands an operator with high skill and experience.Any attempt to repeat a normal "dry and shield" treatment will cause a new failure. Until now the only reliable solution has been a total removal of the laminate layers down to the ultimate ones with any trace of "osmosis" damage and a re-lamination as described in 3.2.. The cost of such a repair often exceeds the value of the boat. Now the HYAB OsmoCure technique in most cases provides a permanent but much faster and less costly solution to the problem. Blisters also might recur because a solvent type primer or filler has been used under the water shield, or if one epoxy coat had developed an amine blush before the next coat was applied. Such blisters are easy to repair.
3.1. Repair of solvent or amine blush blisters. Solvent blisters have a neutral content, amine blisters have an alkaline content. Always test a lot of blisters all over the hull to ensure that there are no acid ones. If any blisters are acid, the repair must be performed as described in 3.2.. 3.1.1. Sand away all blisters. In case of amine blush the total effected epoxy layer must be removed. If bared filler under the blisters proves soft or pulverised it must be removed. 3.1.2. Wash with citric acid or vinegar solution. Sponge the total surface with a 10% citric acid or vinegar solution. Rinse with fresh water after 10 - 15 minutes 3.1.3. Heat the hull to evaporate remaining solvents. Either IR (1000 W for each 10 m²) for at least 60 hours or treatment with the HYAB Osmolance for 5 minutes / m² are the most accurate methods. 3.1.4. Restore the water shield. Use solvent free epoxy filler to even the surface, sand and apply two new coats of water shield.
3.2. Repair of recurring "osmosis" after any type of repair.
Use a peeling machine or other suitable tools. If any gel coat remains under the water shield it must also be removed. Grind away all filler spots left from the earlier repair. 3.2.2. Let the sun or IR armatures heat the bared laminate. A lot of small brown spots, possibly leaking fluid, will then appear on the surface after a few days. 3.2.3. Obtain laboratory tests on laminate samples. Choose 3-4 of the worst spots and drill out 30 mm Ø test samples
right through the total laminate. Let a laboratory check how
far into the laminate salt solutions, glycol and acids have entered.
Peel off all of the original underwater hull laminate down to this depth. Wash thoroughly and dry the hull sufficiently. 3.2.4. Re-laminate with vinyl ester or a laminating epoxy. The epoxy might seem expensive, but used together with quadraxial e-glass mats, the new laminate only needs to have 50% of the removed layer thickness. Fill with solvent free epoxy filler and apply one coat of preferably a solvent type water shield, which will provide the best grip for the antifouling. 3.2.5. The HYAB OsmoCure is safer and less expensive. Now the HYAB OsmoCure technique allows for a total sanitation of the "osmosis" affected layers without removal of more than the new laminate on top. In combination with the OsmoCure Penetrator, one single epoxy/fibreglass layer will be sufficient to restore the strength of the hull. The OsmoCure further provides a faster and less expensive technique for removal of the top layers than other peeling procedures. HYAB licensed Operators and Surveyors can also determine the severity of the damages without removing samples for expensive lab tests.
3.3. Repair of hulls with deep total de-laminations. In large hulls often the recurring "osmosis" causes a total separation between two or more laminate layers. This depends on heavy woven roving mats used in construction and/or the fact that too long a time has elapsed between the applying of some of the construction laminate layers. 3.3.1. Deep de laminated hulls earlier decided irreparable. A repair using currently known methods would need removal of all laminate on top of the deepest situated de-laminated layer and at least one layer underneath. Any attempt to remove only the blistered new laminate and perhaps a few more, to dry and re-laminate will fail. The acid filled capillaries in the old remaining laminate would immediately cause a new blistering. As a total laminate removal and re-lamination is usually too expensive compared to the value of the hull, such damages until now have been thought irreparable. 3.3.2 Repair is now possible with the HYAB OsmoCure. The HYAB Osmocure technique is described in a separate book by the same author.
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