Or How to stick things to canoes
Using glue (Adhesive) is probably the most versatile way of attaching things to your canoe hull. It allows you to position things where you want them, even below water line, does not harm the structural integrity of the hull and with care it is usually possible to remove them in the future. When things go wrong it is often because the wrong adhesive was used in the first place. To form an effective bond you need to use one that can overcome the surface tension of the two materials that you are trying to stick together: some materials, notably plastics, have a high surface tension so some care is required in choosing the right one. The other reasons that bonding fails are poor preparation and not following the instructions. It is no good reading them AFTER you have stuck your D-Rings in!
For canoeists this probably means kneeling pads. Although we don’t want these to fall out they don’t experience an excessive load and mostly the force is sideways, known as a shearing motion which gives the glue the easiest life as the whole of the stuck surface gets a chance to resist the force being applied. From a practical point of view we may also want to replace the pads at some point if they wear out. The best glue to use for this is a contact adhesive, one that bonds as the two pieces are brought together. This removes the need to hold the flat pads on to the curved canoe while the glue sets. Good old Evo-Stik is still probably the best, in the red or green tin, solvent based so you will need to take the little card up to the counter in the store.
Once you have decided where you want your pads mark round them with a pencil and gently sand inside this line. I generally use wet or dry paper though the new Brillo pad style sheets are good. Next wipe the area with some meths to remove any dirt or grease and allow to evaporate off. Apply the glue thinly to both pad and canoe with a ridged spreader. This will make a pretty pattern and is supposed to help adhesion. Next comes the tricky bit. Wait. Go and have a cup of tea. Check your emails. Talk to your partner. Just wait. You need to let the glue dry and all the nasty solvent escape. If not the bond may not work and the solvent could work its way through into the hull and make it delaminate or go wobbly.
When the glue is touch dry, probably about 10 minutes, carefully position the pad over the marked area. Then, bend the pad so you can roll it down onto the canoe. Start at one corner, applying pressure as you go. As contact adhesive sets immediately you need to get it right first time but at least with knee pads there is no need to be millimetre perfect.
Things become much more critical where structural bonds are concerned. If you have a Discovery or one of the other polythene based boats then you will need to take additional measures to ensure that your work doesn’t come adrift.
Although the canoe dealers tend to sell stuff like Vynabond for sticking in D-Rings by far the best glues are the family of viscous polyurethanes that have come onto the market in the past few years. These also work well for items such as pedestal saddles and can also be used for filling gouges in the hull. Although once the preserve of professional users they are now marketed by Evode for DIY use. I have mostly used Loctite professional range (£8 ish for a cartridge) but I can foresee me switching to the new “Serious Stuff” or “Wet Grab” in the next boat I outfit. At around a £5 for a cartridge this is better value especially when you consider that you only need part of a tube and the rest goes to waste. These adhesives bond well to almost all plastics provided you take time to prepare the surface before sticking things down. Roughen the surface and clean thoroughly with meths or another similar degreaser before applying the glue. Adhesive is only needed for one surface and again should be applied thinly with a corrugated spreader. To improve adhesion Old Town recommend reducing surface tension by flaming the surface of their PE canoes with a blow torch set to yellow flame before applying the adhesive. An alternative to this is a primer such as the ones made for the professional adhesives. These are however pretty nasty so make sure you work in a well ventilated space or better still use a respirator. Polyurethanes do require time to set so should be left overnight before applying any load.
If you have a composite or wooden canoe then things get so much easier. Adhesives hold much more easily than with other plastics and there is no need to buy expensive D-Rings. A piece of 50mm webbing with a D-ring sewn on and saturated with boat-building epoxy will stick perfectly well to the hull and forms a strong attachment point. Webbing can also be used on Royalex hulls if you saturate the underside with thin polyurethane such as Aquasure or Seamgrip to create a surface for the polyurethane to adhere to. Leave this to cure for a couple of days then stick down as you would a vinyl pad.
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