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Adam Harrington
6 years ago
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by Cliff Jacobson photo PFBC file photo Many years ago, I watched what appeared to be a new fiberglass canoe scrape its way down a rapid I portaged around.

His bright green canoe looked like new. He said he learned how to repair it by attending a seminar sponsored by the U.S. Canoe Association.

1 by Cliff Jacobson photo PFBC file photo Many years ago, I watched what appeared to be a new fiberglass canoe scrape its way down a rapid I portaged around. I hailed the man and asked him how he could subject a beautiful canoe to such abuse. "I just hope I live long enough to wear it out," he grinned. Later that summer I saw the man at a canoe event. His bright green canoe looked like new. He said he learned how to repair it by attending a seminar sponsored by the U.S. Canoe Association. I joined the organization that day and soon became a canoe fanatic just like him. You don't need special skills to fix fiberglass canoes. It's easy work and there are lots of second chances if you mess up. Once you get the hang of it, you can usually mend minor gel coat damage in an hour and major breaks in half a day. And what works for canoes works for any boat. For example, in 1977, I bought a 14 foot sailboat, trailer and all, for $700. The previous owner had run over a wing dam and seriously holed the hull. A marina quoted $300 for repairs. I bought some fiberglass and resin and spent a sunny Saturday mending the tears. Three years later I sold the boat for $900. Field repairs Generally, it's best to stick with duct tape for field repairs of any boat and save serious patching for the controlled conditions at home. Fiberglassing along a river bank without the proper tools like sharp scissors and power sander may later complicate a proper job. Permanent repairs First, some terms: Fiberglass cloth is composed of twisted strands of fiberglass that are woven at right angles to one another. Cloth has the highest glass to resin ratio (about 1:1) of all fiberglass materials, and also the greatest strength. Six or 7.5 ounce per square yard cloth is the most practical weight for mending canoes. E glass and S glass. E glass is the common boat building fabric and the one you should use for most canoe repairs. S glass a patterned material is much more abrasion resistant and expensive. Episizetm biaxial tape: Two layers of 15 ounce per square yard non woven E glass are lightly stitched together at 45 degrees. Biaxial tape comes in 4 inch wide, 10 and 20 yard rolls. The material is bound at the edges so it's easy to apply along a keel line. For invisible

2 repairs, cover biaxial tape with one layer of 6 ounce E glass. Kevlar cloth. This incredibly strong, very expensive "aramid" is used in police flak vests and as a tire cord fiber. All the best fiberglass canoes use some Kevlar to reinforce delicate areas. Kevlar is much stronger and more abrasion resistant than fiberglass cloth. Mat: Chopped, cross linked glass fibers that are held together with a dried resin binder. Glass to resin ratio is about 1:3, which makes mat one third as strong as cloth. Mat becomes very stiff as it absorbs resin, so it's often used in canoe bilges to improve rigidity. Many layers of fiberglass cloth will stiffen an area as well as mat. And the resulting repair will be lighter and stronger. Gel coat is a micro thin waterproof resin on the outside of most fiberglass and Kevlar canoes. It resists light abrasion, but it breaks when the canoe hits rocks. You can replace broken gel coat, but not without a fight. Gel coat is difficult to apply and almost impossible to obtain a perfect color match to most boats. The section on mending gel coat shows how to make cosmetic repairs without using gel coat. Colloidal silica is used to thicken epoxy resin. I use it to fill deep cuts and gouges. Colloidal silica is very strong and it sands easily. Resins: There are polyester, vinylester, and epoxy resins. Epoxy is the strongest and best for repairing canoes. Special boat building epoxies like Ad Techtm, System Threetm, and West Systemtm are worth their high price of over $80 a gallon. They come with accurate measuring pumps so you won't waste resin by pouring more than you need. MEKP. Methyl ethyl ketone peroxide. The hardening agent used for polyester resin. Comes in small plastic tubes and smells awful. Dangerous stuff it'll blind you if you get it in your eyes! You don't need MEKP if you use epoxy. Essential tools Very sharp, long bladed scissors, orbital and rotary power sanders, saber saw, cheap paint brushes and plastic squeegees, like those used for body work on cars. You'll also need clean tin cans, paper cups, and glass or polyethylene containers for mixing resins. Never mix resins in a container that holds uncured resin! Safety Goggles, gloves, and dust masks: Laboratory safety goggles, plastic gloves and dust masks are essential. You'll use lots of gloves and masks, so you might as well buy 'em by the box. Be sure to take all appropriate safety measures. Always mix and apply resins in a well ventilated (outside!) area, and wear a good dust mask when you sand fiberglass. Use a new mask for each sanding project. Protective skin cream (barrier cream): Helps protect your skin from contamination by resin or solvents that get through gloves. Solvents: You'll need special solvents to remove resin from tools. Acetone is the standard for polyester; epoxy thinner for epoxy. Always wear barrier cream and gloves if you use these dangerous solvents! Some waterless hand creams will remove some resins from skin. Household vinegar is fine for cleaning tools, but not skin! Vinegar dissolves epoxy just enough to allow it to go deep inside the subdermal tissues of your skin. This increases the chance of an allergic action and who knows what later on? In your hair and on your skin! Washing with soap and water seldom removes the tiny fiberglass fibers that cause your skin to itch. In fact, washing may drive the glass particles deeper! Try using a vacuum cleaner to swoop up abrasive dust. If discomfort persists, apply masking tape to the affected area and then gently pull the tape off like you're removing lint from clothes. This usually works. You may also wash the affected area with a good hair conditioner. The conditioner seems to lubricate and smooth the fibers. Rinse your skin thoroughly after you've applied the conditioner, as you would for hair.

Scratches Shallow scratches can often be polished out with auto buffing compounds. Use a light touch on the buffer bear down hard and you may cut into the glass or Kevlar below!

3 Scratches Shallow scratches can often be polished out with auto buffing compounds. Use a light touch on the buffer bear down hard and you may cut into the glass or Kevlar below! Deep scratches are best left alone, unless they are so deep that they abrade the glass or Kevlar beneath. If fiberglass or gold furry stuff (damaged Kevlar) protrudes from the scratch, you'll want to make repairs. If the damage is light, simply flow epoxy resin into the cut. When it has hardened, polish it out and paint it. Heavily scored or broken Kevlar should be covered with a fiberglass patch. Fair the edges of the hardened patch into the surrounding hull, and then paint it. Use fiberglass for cosmetic patches. Kevlar cannot be sanded! Mending gel coat One trip down a rocky river and you'll need to repair the gel coat on the nose of your canoe. Gel coat repair kits do a good job if you're very patient. The book procedure calls for filling the break with color matched liquid gel coat (which is runny and hard to contain), and then sanding and polishing to blend the repair. This is slow, frustrating work, and it's almost impossible to get a perfect color match. This procedure is easier and faster, and the finished repair is invisible. Materials Procedure White polyester putty (available at marinas) or gray auto body putty. Use epoxy if you want a stronger repair. Thicken the epoxy with colloidal silica, as suggested in number 2 below. Sixty and 100 grit dry sandpaper, and 200 and 400 grit wet dry finishing paper. Matching auto acrylic or epoxy paint. Fiberglass boat wax (it contains a mild abrasive) or paste wax and pumice. 1. Pick out the shards of damaged gel coat. 2. Catalyze the polyester putty (use extra MEKP for a hot mix) and work it into the break to overflowing. If you're using epoxy, stir in colloidal silica until you get a peanut butter thick mix that won't run. 3. When the resin has cured, sand it level. Finish to silky smoothness with 400 grit wet sandpaper. 4. Paint the patch. Later, use a mixture of paste wax and pumice to blend the paint to the hull. If you have a natural gold Kevlar canoe, or one whose color you can't match, repair the gelcoat as described above then mask a short, artificial waterline along the bow and stern (see Figure 1). Paint the masked area an attractive color. The paint will hide your repair.

4 graphic Ted Walke Skid plates Some paddlers glue thick Kevlar "skid plates" on the ends of their canoe to protect them from damage. Here's why this may not be a very good idea: 1. Kevlar skid pads may absorb a pint or more of epoxy resin, which increases the weight of the canoe by several pounds. This weight is added at the extreme ends of the canoe, which affects its "swing weight," or ability to carve and check turns. If you want to turn a highperformance canoe into a barking dog, just add some weight to its ends. You'll notice the flywheel effect immediately. 2. You can't sand Kevlar, so the harsh edges of the thick felt pads won't fair in to match the contours of the hull. The result is increased wetted surface and noise. Here's a better plan: Lightly sand the area to be patched and cover it with one layer of biaxial tape. Saturate the fabric with resin (a plastic squeegee works better than a brush). Then lay an oversized "cover piece" of 6 ounce E glass or S glass on top. Work resin into the material until the "cover patch" is saturated. When the resin is dry, fair the edges and lightly sand the surface of the fiberglass until it is smooth to the touch. Spray paint to match the hull. Two essential patches These two patches can repair most any boat: 1. Double sided patch. The damaged area is accessible from both sides of the hull. Cut out the splintered glass with a fine toothed saw. Feather the inside edges of the hole with a rotary sander. Place plastic wrap, wax paper or aluminum foil over a flexible piece of cardboard and tape the cardboard wrap side against the hull to the canoe (Figure 2a). Cut several fiberglass cloth patches to fit into the hole from the inside of the hull. Cut each patch slightly larger than the previous one to accommodate the increased taper (feather) of the hole (Figure 2b). Wet out the patches on a board and place them into the hole smallest one first, then the next largest, until the patches are flush with the hull. Cut a large "cover patch" to seal the smaller patches. It should extend beyond the last patch, at least an inch all around. Be sure the area around the hole has been sanded so the patch will stick. When the repair is dry, remove the cardboard form and sand off the gel coat about two inches back, all around the repaired area. Apply an oversize fiberglass cloth patch to the outside of the hull. When dry, sand and feather both cover patches until they blend with the hull. Finish to silky smoothness with 400 grit wet sandpaper. Paint the mended area with matching auto acrylic or epoxy enamel. When the paint has dried, polish out the patch as in step 4 of "mending gel coat," above. Tip: You can increase the strength of your repair by substituting one or more layers of Kevlar for fiberglass. Remember, Kevlar can't be sanded, so always use a fiberglass "cover patch."

graphic Ted Walke 2. Single sided patch. The damaged area is accessible from one side only. Use this method when flotation foam prevents you from getting to the break.

Cut two fiberglass cloth patches (substitute Kevlar if you want more strength) the size of the cardboard. Place the patches on the cardboard, and wet them out with resin.

Force the wet glass/cardboard form into the hole (you'll have to bend the cardboard slightly) and align it so the cloth butts against and overlaps the inside edges of the hole.

This will keep the patch tight until it dries.

5 graphic Ted Walke 2. Single sided patch. The damaged area is accessible from one side only. Use this method when flotation foam prevents you from getting to the break. Cut out the bad glass and feather the outside edge of the hole. Cut a piece of cardboard to the approximate shape of the hole, only slightly larger and more oval in shape. Cut two fiberglass cloth patches (substitute Kevlar if you want more strength) the size of the cardboard. Place the patches on the cardboard, and wet them out with resin. Run a small copper wire through the center of the cloth and cardboard, around the popsicle stick, and back through the glass covered cardboard (see Figure 3). Force the wet glass/cardboard form into the hole (you'll have to bend the cardboard slightly) and align it so the cloth butts against and overlaps the inside edges of the hole. Pull on the wire to tighten the form against the inside hull. Then, wrap the wire around a wood stick and block the stick at the ends. This will keep the patch tight until it dries. When the patch is dry, snip off the wire and complete the repair from the outside hull like the single sided patch described above. Note that the cardboard form and popsicle stick remain inside the boat (hidden from view ). Tip: Fiberglass patches will adhere better to tightly curved areas if you cut them diagonally across the weave, as illustrated in Figure 4. graphic Ted Walke

I am indebted to Bob Brown, past building chairman for the

sailboats. Remove the chards of broken gel coat.

If you use epoxy, thicken it with colloidal silica to a peanut

6 I am indebted to Bob Brown, past building chairman for the Minnesota Canoe Association, for these unique ways to repair fiberglass/kevlar canoes. Bob has designed and built dozens of canoes, kayaks, and sailboats. Remove the chards of broken gel coat. Catalyze the polyester resin and apply it to the break. If you use epoxy, thicken it with colloidal silica to a peanut butterlike thickness. Paint, polish and wax. sequence photos Cliff Jacobson Sand the hardened resin flush with the surrounding gel coat.

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