At the start of the season, polishing the hull and superstructure is on almost every skipper's to-do list. However, the results are as heterogeneous as the products are varied. But what are the optimum products for each application? And how should they ideally be applied? With a machine or by hand? When is the best time to polish? And does it make a difference how old the gelcoat or paint is?
Goal: Maintain gelcoat
"The aim is to preserve the gelcoat for as long as possible; varnishing is the last resort," explains Stephan Clausen from the Hamburg-based company Rüegg, which sells both polishes and varnishes. However, the outer protective layer over the laminate is permanently attacked by environmental influences such as UV radiation, dirt, salt water and fender abrasion.
This causes microscopically small fragments to detach from the surface, leaving behind a miniature moonscape. Logically, this enlarged surface offers more opportunities for soiling and therefore for further wear. In addition, the reflection of light on the no longer flat surface is impeded and the gelcoat appears matt.
If this process is at an early stage, i.e. the gelcoat is quite new, a simple polish can fill in the small craters that have formed. The surface is smoothed, so to speak. This makes the boat better equipped to withstand the environmental influences mentioned above.
If a boat is protected in this way from the outset, its condition can be maintained for many years. But even if simple polishing is no longer enough to achieve a glossy finish, there is no need to resort to paint and brushes straight away. "A gelcoat is 1.2 to 1.6 mm thick," says Andreas Woyda, application technician at the Yachtcare care professionals.
It is therefore possible to remove the top layer if the resulting craters are deeper than a polish or wax can fill. Manufacturers offer products with abrasive components for this purpose. During application, they remove the peaks between the craters and thus enable a new shine to be achieved at a deeper level. Unfortunately, it only becomes clear when this is necessary after polishing. However, with a little experience, it is possible to estimate whether a dull spot in the gelcoat needs to be treated with an abrasive polish or whether simple sealing is sufficient.
If treatment with sanding paste is necessary, it should be applied as late and as sparingly as possible in order to delay a paint job costing many thousands of euros. For this reason, all manufacturers recommend starting with a fine product for matt areas and only switching to coarser products, which remove more material, if necessary, i.e. if there is no gloss.
Polishing therefore fulfils three functions: It protects the gelcoat and thus preserves its value, dirt is less able to spread on the smooth surface, so the boat stays clean for longer, and the resulting lustre is sure to delight onlookers. But what does an ideal polishing process look like?
Don't forget to clean!
"The first step is to clean, otherwise you will polish the dirt particles into the surface. A good cleaner also removes all residues of old polishes and waxes, resulting in a really clean surface," reports Jean-Pierre Martius, Application Consultant at International Farbenwerke.
After cleaning with special boat cleaners and rinsing thoroughly with clear fresh water, the surface is polished or immediately sealed. If the surface is in a condition that gives hope for a glossy result, this should be done without removing any surface material. If possible, use a polish without any abrasive particles so as not to further damage the existing gelcoat substance.
You can find the complete practical guide with many more tips in the current May issue of BOOTE.
