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How to do it notes: - Gel Coat Repairs
The scope of this guide is very limited and is intended to provide a brief outline to the way gel coat can be repaired away from a professional workshop. The results that are obtained will depend largely like all repairs upon the skill and care of the operator.
Take time and work in a warm well lit environment and you will find that you produce better results.
Small chips and knocks
By small we mean no larger than a 10 pence coin.
Sand back the damage to produce a dished area with the sides and base of the chip well sanded with P400 paper dry. If the dished area is very deep (greater than 2mm fill using car body filler to level the damage)
Clean the area with acetone or a lightly wetted cloth and allow to dry. The use of white sprits is not recommended, however meths may be a suitable alternative.
Form a dam around the scuffed up area using masking tape or plasticine to prevent the gel coat from running out of the repair.
Mix up a small quantity of gel and apply to the repair. Build up several layers of gel to bring the repair proud of the surrounding surface. The gel will shrink as it dries.
Once the gel coat has dried and is hard using a small hard wooden block sand back the new gel using P400 paper and plenty of water. The use of a 2B pencil scribbled over the surface will highlight lower or rippled surfaces.
Once the gel is level with the surrounding area change to P800 paper for a few strokes or until the scratch marks from the P400 have disappeared. Continue up the grades until you have reached P1500 by which time your repair should have taken on a sheen and be almost invisible.
Finally polish using a car type compound to bring the gloss up to match the glider.
Medium and large sized areas
It is important to ensure that any surface upon which gel is to be applied is suitably scuffed or keyed. Without this keying the gel will neither adhere nor will you be able to lose the edges of the repair. The minimum grade of paper to use is P400. Maroon Scotchbrites from many hardware stores are a good alternative.
Filled or otherwise prepared repairs or damaged gel should be scuffed up using P400 paper and the area around the repair should be masked out. A "frame " of about 75mm is about right for "loosing" the repair into.
For best results apply gel using a spray gun to build up coats. However good results can be obtained using patience and a good quality paintbrush. Sanding between coats whilst spraying should not be required however sanding between coats when brushing will reduce the build up of lines and make final finishing quicker. Alternatively brushing at 90 deg between coats reduces this build up
Once the gel coat has dried and is hard, using a small hard wooden block sand back the new gel using P400 paper and plenty of water. The use of a 2B pencil scribbled over the surface or a thin coat of cellulose lacquer will highlight lower or rippled surfaces.
Once the gel is level with the surrounding area, change to P800 paper until the scratch marks from the P400 have disappeared. Continue up the grades until you have reached P1500 by which time your repair should have taken on a sheen and be almost invisible.
Finally polish using a car type compound to bring the gloss up to match the glider.