In comparison to traditional building materials, Fibreglass composite materials are generally easier to repair.
It is important to note that once the original fibreglass laminate is damaged, any repairs to the original are considered as secondary bonds. With this in mind, the materials used to repair the laminate should be as good as what the laminate was constructed with. This is particularly important for resin choice. For example, if the laminate was constructed with an Epoxy Resin it should be repaired with an Epoxy Resin.
Any repairs should be matched as closely to the original repair as possible including thickness, density and ply orientation. This will avoid any further stress to the laminate.
Depending on the damage to the laminate, different repair techniques may be required. The steps below outline a standard fibreglass repair. If you require more assistance don't hesitate to contact us or view our FAQ section.
Undertaking the Fibreglass Repair
Inspect the area and identify required materials
Damage to the laminate can present itself in four ways; Tears, holes / punctures, crushed core laminate or delamination.
Care should be taken to ensure that the damage hasn’t spread further than the initial visual inspection. Tapping a coin on the surface of the laminate to detect any sound changes between crushed or solid laminate is one way to detect further damage.
Measure the area to be repaired and choose your required materials. As mentioned above, care should be taken to ensure the original type of resin is used. Finally, choose the type of glass fibre reinforcement that you will need.
Remove damaged material and prepare area for repair
Grind down the edges of the repair area with a disc sander and wipe down with Acetone. It is important that whilst not too much solid material is removed (don't grind down past the fibreglass), an allowance of 2/3 inches wider than the inside edge. This will ensure there is a solid surface for the materials to bond.
In cases of deeper scratches, milled fibre may be mixed with Resin before adding the catalyst. The mixture should be the same consistency as mayonnaise. This should then be applied into the repair. Once cured, the area may be sanded as required before moving on to the laminating stage.
Laminate the damaged area
Pre-cut the glass fibre material into different sized layers (usually about 2 layers are required), one slightly smaller than the area to be repaired and one to cover the grinded down area.
Mix the polyester resin thoroughly with 2% catalyst. 2% catalyst addition at room temperature will normally give a working time of 15 minutes before the resin starts to harden.
Apply the catalysed resin onto the area to be repaired and start to apply the layers of glass fibre.
The smallest piece should be applied first working up to the largest. The larger layer will normally be 20mm larger than the repair area.
Applying the resin with a brush, ensure each layer of the glass fibre material is wet through. There should be no dry patches remaining. Once the resin has been applied, a paddle roller can be used to remove any air pockets.
Once the repair has cured sand the area once again and wipe down with Acetone.
Apply final layer of Topcoat
For a professional, waterproof finish the repair area should be coated with Topcoat. The Topcoat should be mixed with catalyst at a rate of 2% and applied with a brush or roller.
The advised rate of Topcoat application is 500g per m2.
Where to Buy Fibreglass Repair Materials?
Professional Fibreglass Repair Kits
FibreGlassDirect offer a complete range of Fibreglass Repair Products.
Our comprehensive Professional Fibreglass / GRP Kits offer many of the materials outlined above including Lloyds Approved Resin, Fibreglass Matting, Tools and Topcoat.
These kits can be used for all kinds of repairs including General DIY, Gutters, Roofs and Boats.