February Technical Meeting — Jotun Paints
Our guest speakers for the February technical meeting were Dean Coxon and Dave Simpson from Jotun. Dean introduced Jotun as an international coatings company based in Norway and focussing mainly on commercial applications in Perth. However, they do have agents for a limited range of their products in the retail market place. These include Boating Hardware and Robayne Distributors.
The format of the night was largely determined by the particular interests of those attending and a question and answer approach which covered a great deal of territory over the ensuing hour and a half.
We commenced with the treatments required for raw wood – those being an all-purpose wood primer (not metallic type) that is suitable under both anti foul and deck paints. A note of caution was issued in respect to leaving this sort of primer too long between coats or before top coats as chalking can develop. It is also recommended that the surface have a light sand between coats. A question was asked about the use of rot proofing type products and the advice was that they should only be used where the wood requires this sort of treatment.
Moving on to antifouling, the recommendation was that a good pressure clean at 3000psi is sufficient and if the surface is sound, no more existing anti foul needs to be removed and sanding was not signalled as necessary. For new wood below the waterline, a tie coat between the all-purpose primer and the antifoul is recommended. Jotun Vinyguard provides such a tie coat. Application of antifoul is best achieved via spray which can achieve an even thickness of 300 to 400 micron with two coats. Next best is application with a roller which achieves a more even coat than brushing but at approximately 100 micron per coat may require three coats to achieve the recommended film thickness.
Antifouls are either ‘self-polishing’ which have less biocides or ‘contact’ antifouls which are harder and have more biocides (ie highest copper content). Jotun antifoul is available in a three tier system for a protective life of 1, 3 or 5 years. These are variously branded SeaQueen, SeaForce, SeaGardian and SeaQuantum.
We then moved to discussion on paints for metalwork. Firstly for aluminium such as masts, a thorough clean to remove any wax and grease should be followed by a sand with 3M type fibre discs. In some cases, an etch primer may be required but generally a primer such as Jotun Penguard HB will provide a good base for the 2 pack epoxy top coats. For stainless steel, normal sanding is really not adequate to achieve a good paint key and a grit blast is recommended. In this regard it was noted that a small grit blaster suitable for amateur use is available at Supercheap Autos.
Discussion then changed to topcoats. Jotun gloss topcoats available in Australia are generally not designed for brushing or rolling. It was noted that polyurethane topcoats come in a linear form which is repairable (buffable) and a non-linear form which are not repairable and must be sprayed. However, decks could be rolled with Hardtop and will provide a good anti slip surface with grit added.
In concluding, Dean and Dave emphasized that the most frequent problems that they respond to can usually be traced back to unsatisfactory preparation or inadequate mixing of the paint. The latter is particularly important for antifouling paints which contain a high percentage of copper and other components which very quickly settle to the bottom of the can.
The evening closed with Dean and Dave making available a range of CD’s, brochures and other written material on Jotun products which may be of interest to members. Much of this material is also available on their website at www.jotun.com for those that may not have been able to attend on the night.
We thank Dean and Dave for making their time available to provide us with a most informative night of advice based on their considerable industry experience.