fiberglass4

PART FOUR - Compound & Major DamageCompound Damage:This type of damage, which requires laminating from behind, is fairly straightforward in that the top surface is always treated as a large gel crack.Resin brushed onto prepared areaIf there is a simple split, say, on a wheelarch, thoroughly clean the underside of all debris and underbody sealant and use the grinderette with an 80 disc and abrade the surface to form a key, then go 3 - 4 inches either side of the split, and lay up these to form layers of 300 gr/m (old 1 oz/yd) mat, wait until it is fully set and attack the top surface as described earlier. If the split has 'ridden up' , one of two things can be done. Run a hacksaw blade or jigsaw blade up the crack; this will remove the jagged edges and you can press the edges flush again. If the crack is severe then, after laminating underneath, grind into the new laminate on the top surface and use one layer of mat plus the tissue for the 'gel crack' repair. For major compound fractures that don't require sections the area may have to be pieced together like a jig-saw using clamp plates to hold it fast. Always clamp from the top (painted surface) and laminate using four layers. when it is set remove the plates and denib the screw surrounds with the grinderette. The structure is now sound again but the top is still a mess so grind the whole area and, if extensive either drape one layer of mat plus tissue or two layers over this. When it is set fill as described earlier and get the contour right. Remember the filler acts only as a veneer so it MUST NOT go on three inches deep because it will only crack away again. We have all seen superbly resprayed GRP cars which, given a slight 'ding' on a wheel arch, have shed two tons of filler from the entire wing due to a previous repair! All the strength of the repair is derived from laminating and filler is to give the cosmetic shape ONLY.Filler being appliedMajor Damage:Major accident damage which requires replacement sections can get complicated but buy only the repair sections you actually need; don't buy half the front when you only require a quarter front, panic sets in at the thought of cutting off half the car to bond on a new section but just remember to strip out everything around the bonding line and MEASURE it all correctly first BEFORE you cut it away. Use reference points i.e. chassis fixings, bonnet, door openings, windscreen points, then cut off the damage and offer up the new piece. Local jiggling and cutting will result in the final fitting and, when you are satisfied, clamp (or rest) the new section in place temporarily and check the FIT of door, bonnet etc.; do it BEFORE everything is stuck solid and you cannot shut the door. Prepare the old and new surface thoroughly, go back at least 12 inches beyond the join and the re-align and clamp on. Spread the load away from the join with at least four to five layers of laminate and, when it is set, remove the clamps, grind into the new laminate and then join and feather out to at least eight to nine inches either side. DO it as described earlier but place two layers into the join and grade out, finally using tissue and filler. The join is inherently strong because you have made the whole new join with fresh laminate. NEVER just butt join two sections as eventually the whole line will appear at the butt. I've actually had an Elan rear section fall off where the owner had just butt-joined them up with one layer only underneath and filler on the top. No one will ever know that a correctly fitted section has been put on. Approximate times for this type of repair (depending on car) vary between 10 - 50 hours.

A final piece about 'bolt on' GRP panels, either to GRP cars or metal. With like with like bolt through panels on GRP cars use a silicone sealant between them first and use the largest washers available to spread the load. Do the same with metal or even sit the panel on a thin piece of isolating rubber strip; glazing rubber is ideal. If any panel is to be bonded on it is essential first to key the area well and use three to four layers graded out. On metal all rust must be removed and use a course disc 40 or 80 grade to provide the key; the bonding must be perfect with no air bubbles if possible, cross bolt as well because metal will always expand and contract at different rates from GRP. Remember, NO STRUCTURAL METAL MUST EVER BE REPLACED BY GRP PANELS. Apart from the fact that it is illegal, it is also highly dangerous..