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HOW TO: REPAIR YOUR KAYAK

Although it is unlikely that your kayak will need repair during its lifetime, it is possible that a hull crack or puncture might occur due to extreme impact or contact with a sharp object. If this happens, first contact us or your Wave Sport dealer to determine if the damage falls under the boat's warranty.

We will need the serial number of your kayak (find your serial number), a good description of the damage (a photograph is very helpful), and a description of the incident during which the damage occurred. All this information will help us to determine the best course of action in getting you back on the water. As an owner of a boat made from polyethylene plastic, one repair option which may be available to you is welding.

Polyethylene is recyclable and repairable, unlike many other plastics. Incidents necessitating welding happen to less than one percent of boats, but if for some reason you should get a crack or hole in your boat, refer to the following repair instructions or call us for additional assistance.


COSMETIC ISSUES & REPAIRS

Cosmetic damage is defined as something that impairs the boat’s appearance but not its function. On polyethylene boats cosmetic damage usually takes the form of abrasion, superficial slits, cuts or gouges, and localised dents in the hull panels.

ABRASION

Abrasion is basically due to wear and tear and is often localised.  Abrasion often takes the form of a series of scrapes and shallow gouges and in most cases doesn’t need to be attended to unless over time damage continues to accumulate to the point where gouges become deeper. This type of damage will transition from cosmetic to structural when there is a difference in the flexibility between the abraded section and neighbouring hull sections. Easiest way to test this is to press on the hull with your palms and compare the resistance. If you’d simply like to make your hull look better you can use a sharp knife (x-Acto® type is good) to cut away any raised edges along sides of abrasion. A file or Surform® rasp can also be used effectively to smooth out the hull surface. Unfortunately, painting is not an option as paint will not adhere to polyethylene.

SLITS & CUTS

Compared to sharp edged river rocks and ledges and even coarse grained sand, polyethylene is a soft material. As such, it will come out second best when the inevitable collision occurs. Abrasion is one result and a second consequence can be superficial cuts or slits in the hull. These are primarily noticeable by the raised edges on either side of the cut. Again isolated cuts are not a structural concern. To lessen the cosmetic impact, use a sharp knife, file, or rasp to remove the raised material. A rotary tool such as a Dremel® can also be used effectively to remove the feathered edges.

GOUGES

Gouges are a tough one. At first, it would seem likely that a gouge could easily be filled and smoothed but polyethylene doesn’t provided a good bonding surface for new material and the inherent flexibility of the material poses a challenge to the bond between original material and filler or new material. Other than smoothing the edges of the gouges as you would with slits and cuts, it’s often best to accept and live with it. If you’d like to try to fill the gouge, you can follow the instructions for filling cracks included in section on structural repair.

DENTS

Dents can result from impact from paddling or a weight left resting on the boat. Long term storage in one position can also produce hull distortions. Prolonged or continual exposure to sunlight can distort or stress the hull and create depressed sections of the hull. Tying your boat down tightly on your roof racks for a lengthy time, particularly on sunny hot days can result in dents and deformations. Generally, prevention is the best solution to this type of damage. Periodically ease your tie down ropes or straps. Store your boat suspended in web straps or resting on rigid sections of hull. Getting an idea of the source of the dents in the hull can help prevent future damage but doesn’t help deal with those already in existence. Just as heat is the source for some dents and deformation, it can also provide the solution. Our polyethylene has an excellent memory and its recall can be encouraged by heat and pressure. Minor dents can sometimes be removed simply by leaving the boat exposed to bright sunlight and applying a gentle pressure on the inside of the hull. If the dent proves stubborn, you can increase the heat by using a hair dryer. If still more is needed, a hot air gun may be suitable but must be used with care. Keep the gun at least 25mm from the hull and in constant motion. Watch carefully for any signs of glistening or melting of hull surface. Apply pressure from inside of hull while applying heat to exterior. Have gloves available to protect your hands while hull heats. An alternative approach is to rig a brace to apply consistent pressure to inside of hull while boat is exposed to sunlight or heat.

STRUCTURAL REPAIR

Structural damage can affect the hull. A caulk or sealant would seem a likely candidate as a repair material but unfortunately, polyethylene does not lend itself to a long-term bond with any sealant. Probably the caulk that performs best with polyethylene is Lexel ®, used by many manufacturers to seal the junction between minicell bulkheads and the interior of the hull. However, even the best sealant will not adhere well to polyethylene by itself. Bear in mind that the bond between bulkhead and hull is reinforced by the compression of the fitting. The same goes for sealing cockpit rims or similar applications. Caulk or sealant can make the junction between fitting and hull drier but only if used as the filling between the fittings, contained and compressed by mechanical fasteners such as rivets or nuts and bolts.

NOT ALL POLYETHYLENE IS THE SAME….. Our “super” linear polyethylene has finely tuned properties that are specifically geared to withstand the rigours encountered in the life of a kayak. We recommend that you obtain “offcuts” or welding rod made from the original material before you attempt to make a repair to your kayak. This will provide you with the best possible repair.

CRACKS

The most common structural damage “poly” boats suffer are cracks or linear breaks. In many cases, these are repairable but the process is challenging. You will need the following tools and materials to attempt a repair of this type of damage: - hot air gun with reducing nozzle or propane torch - wire cutters - drill (can be done without) - drill bits (3mm - 5mm) - file or rasp - sharp knife - fine edged metal putty knives (2) - vice grips (pliers can work) - coarse grit sandpaper – gloves – meths or acetone (in the context of the steps of this process it is important to remember they are highly flammable)- polyethylene welding rod/offcuts to cut into narrow strips (As noted above it’s best to use material provided by the manufacturer of the kayak to be repaired). First, thoroughly clean area around crack. Make sure area is very dry. Use heat gun or torch to dry area but use them carefully. Lightly sand area allow each side of crack, sufficient to raise small fibres on surface of hull. Wipe down surface with meths or acetone and allow to dry. Drill hole at either end of crack with 3mm drill bit. If drill is not available, heat end of drill bit with torch, holding bit with vice grips, and melt hole at each end of crack. Function of the hole is to prevent the crack from “walking” or extending after the repair (called notch effect). If your “tool” kit contains a hot air gun: Insert a putty knife into crack so that a slight gap is created. If crack is lengthy, insert putty knives as necessary to open full length of crack. Position knives so that they are at least 25mm from hole at one end of crack. Preheat the first 5mm (approx.) of the poly weld rod to point where rod gets limp and clear as poly liquefies. Starting 5mm beyond one end-hole, apply hot end of weld rod to the hull. Holding the weld rod at an angle away from the crack, begin to push the rod onto the crack, making sure the melted poly fills the end-hole (push rod into hull and rotate, keeping contact with hull at all times. Make sure melted poly enters the gap created by the putty knife/knives. Hold the hot air gun approximately 25-50mm away from hull at a complementary angle to the welding rod and heat rod and crack as you proceed. As you approach the putty knife, if possible slide it further along the crack or withdraw it an angle, always providing a slight gap to allow melded poly to enter. Make sure to apply enough poly so that a slight bead is left on the surface. Continue applying weld rod to crack, removing the putty knife(s) as required. Crack should close as you remove spacers. Make sure that the applied poly from the rod is still hot and liquid as the crack closes behind the point at which you are working. At end-hole opposite to where you started, melt enough rod to overfill hole (insert rod into hole and rotate rod. Make sure you keep end of rod in contact with hull as you push it down into hull and pull it out. Apply rod to hull approximately 5mm beyond hole. Do not pull the rod away as you finish as this may pull some of the applied poly with it. Cut unmelted rod with wire cutters or crimps. Smooth out the bead of poly sitting on top of crack, using gloved hands. Judiciously heat bead with hot air gun and press and smooth with hands if you want a smoother surface. Allow hull to cool completely before moving or disturbing. Test the quality of bond by pushing corner point of putty knife under edge of applied polyethylene and prying up. If bead lifts easily or bead rises down along the crack, you have not achieved a good quality repair. Alternative method using Propane Torch A torch with open flame is fine for generating heat necessary to conduct repair but it is not recommended to melt the weld rod poly directly with a torch. Use a drill bit as described to melt the rod. Drill end-holes at end of crack as described above. Insert putty knives as described to slightly open crack (no more than 2mm). Clamp drill bit in vice grips so that shank or smooth end of bit extends from jaws of vice grip. Heat end of bit until it glows red hot. Apply end of bit to crack in hull and heat the plastic until it begins to melt. Rolling the bit or working in a circular motion is effective. Holding the poly weld rod against hot bit, melt end of rod and drip onto crack in hull. Alternate heating rod and hull surface to keep both hot. It will be necessary to periodically reheat the drill bit to keep it hot enough to do its job. Proceed along the length of the crack, removing putty knife spacers as required. Slightly overfill the end holes and make sure the filler poly from the weld rod bonds well to edges of holes. Once crack and end-holes have been filled, cut end of weld rod with wire cutters. Pass the torch quickly over the repair several times until the repair poly glistens slightly and then smooth with gloved hands. Do not allow flame on torch to contact hull and keep torch moving at all times. Severe hull damage can result from excess exposure to flame or excess heat. Allow hull to cool completely before moving. Test quality of bond as described previously.

SMALL HOLES

Repair of small punctures is similar to filling the end-holes on cracks. For tiny holes, it may be necessary to slightly enlarge the hole first to allow the melted poly to enter and seal the hole. You can enlarge the hole by drilling with small bit or by heating drill bit and melting hole slightly. For best results, heat area around the hole and apply the melted poly from the weld rod to surface while hull is hot. This allows repair poly to bond with hull material as repair cures. Press melted end of poly rod against hole and rotate rod in hole to spread adequate repair material in place. Cut off unmelted part of poly rod. Do not try to pull rod away as this could pull melted poly from hole.

LARGE HOLES

It is possible to weld a patch to your hull but can be a tricky process. As it’s necessary to melt your existing hull surface at point of repair, the possibility of inadvertently further damaging your hull does exist. If possible, rehearse the process on a couple of scrap pieces of polyethylene before attempting on our boat. For best results, obtain a patch of adequate size from your boat’s manufacturer. A hot air gun is preferable to an open flame torch for this repair. Cut the patch so that it is slightly oversized compared to the hole. The patch material can be cut with large wire cutters, jigsaw, or circular saw. Shape the patch so that it is rounded to eliminate sharp edges or corners that could lift if struck by an obstruction. Heat patch until it becomes slightly pliable. With gloved hands hold it in place over area to be patched until it cools and holds a matching contour to that section of hull. Sand the hull surface to be covered with the patch to raise a texture and small feathers of material. Wipe clean with meths or acetone and let dry. Take weld rod and melt a bead of polyethylene in a circle around the hole in hull. Heat the area to be patched until hull surface softens slightly, alternately heating underside of patch as well so that both attain temperature at about the same time. Make sure that bead surrounding the hole is soft and melted. While all surfaces are hot, press patch onto hull and hold in place. Take weld rod and melt a bed along exterior edge of patch, melding patch and hull into one piece. Using gloved finger or flat tipped screwdriver shape bead of polyethylene from weld rod so that it smooths transition from original hull to patch, eliminating sharp edges. Allow patched area to fully cool before moving or disturbing.