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Introduction GRP Basics
Essential Tools
(This page)
BACK TO FULL LIST OF PROJECTS
Introduction GRP Basics
Essential Tools
(This page)
This page describes three relatively inexpensive power tools which in my view are essential for any extensive repair work to a GRP constructed boat.
After taking the decision to restore the gelcoat rather than paint it, the next stage is to wash it and then buff it using an electric polisher with a cutting compound. This will immediately make a big difference to the appearance of the boat by removing faded gelcoat as well as superficial abrasions and scratches. It will then be much easier to pinpoint more severely scratched and abraded plus cracked areas which will need individual repair. At a pinch, an electric drill with suitable buffing pads can be used as a serviceable polisher. However, for ease of use and to obtain the necessary slow-speed, it is best to use a dedicated polisher such as the Rupes BA 31EN illustrated below.
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A Polishing Kit
This shows a basic electric polishing kit. The variable speed electric polisher is a Rupes BA 31EN polisher (also usable as an Angle Grinder). For polishing work it is essential that the speed of rotation of the heads is kept within the range of 1,500 - 2,500 rpm (to avoid damage to the gelcoat through overheating). Lightness is also important for ease of use, the unit shown has a weight of 1.8 Kg. The white polishing pad (shown attached to the polisher), is made from wool and is harsh in action. It is used with coarse cutting compound (in the right hand container), to remove weathered gelcoat and superficial abrasions. The yellow polishing pad is made from synthetic fibres, is softer in action and is used with the finer polishing compound (shown on the left of the picture). This deepens the initial polish obtained using the coarse cutting compound. Click image for full size picture |
In my opinion, this tool, made by Black & Decker, is essential for GRP repairs. It works in a similar fashion to a belt sander but the belt is much narrower, only 13mm (1/2in) wide. Because the belt protrudes from the front of the machine it can be used for sanding in recesses which are inaccessible using most other power tools. With the appropriate sanding belt fitted, areas of cracked and damaged gelcoat can be stripped within seconds exposing the underlying laminate ready for repair. It is particularly useful for dealing with tight corners such as those at the back of the side decks where the gelcoat commonly develops crazing and stress cracks.
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Black & Decker Powerfile
Variable speed Powerfile manufactured by Black & Decker. It has a speed of 900 to 1,400 rpm and a 350w Motor. The model shown here has now been superseded by a newer version but the features are essentially the same. Click image for full size picture |
The following pictures illustrate why the Powerfile is such a useful tool in repairing GRP.
Isolated cracks & scratches have to be cleaned and widened before they can be filled with Flowcoat. A miniature power tool such as the Dremel illustrated below can be used with the engraving and carving tool accessories and is by far the best tool for doing this.
