Poly Repair

Found a crack in my cockpit combing. Poly CD Sirocco. Any advice on cheap repair?

can you talk to the mfg?
Plastic welding should be done by an experienced welder, but may not cost much.

If I were on my own, I might try West G-flex and a bit of cloth reinforcement on the upper side of the flange. Nylon or polyester or even Kevlar. Not glass, which might tend to cut or abrade skirts. You’d need a propane torch to flame the plastic for better adhesion.

West Systems G-Flex epoxy
Jack L

I used G-Flex and fiberglass

– Last Updated: Sep-14-11 9:23 AM EST –

I have a Dagger Cascade C-1 in which about 1/3 the circumference of the cockpit coaming was broken completely through. I repaired that using G-Flex and E-glass.

The break was at the base of the coaming where it joined the deck. To repair a crack with epoxy you need to enlarge and "gutter out" the crack sufficiently to get epoxy into the void. I used a hacksaw blade passed through the crack where necessary to enlarge it, then smoothed the crack and rounded off the squared edges (as recommended in the instructions from West Systems) with folded pieces of sandpaper. The poly then needs to be thoroughly cleaned out with denatured or isopropyl alcohol. After it is dry pass the tip of the flame of a propane torch over the crack and adjacent poly several times to oxidize the surface. The color should not change and the plastic should not become hot. This is a necessary step to get G-Flex to adhere well to poly.

I backed up the crack on the inside of the coaming with clear plastic packing tape to restrain the epoxy, then propped the boat at various angles and filled in the crack piecemeal allowing gravity to distribute the epoxy fully in the crack. I thickened the epoxy with silica powder for this step. I also applied a thin gusset of thickened epoxy along the concavity of the outside of the cockpit coaming over the cracked area, but not so much as to interfere with the fit of a skirt.

Once the crack was filled in, I reinforced the repaired area with a single layer of 8 oz/yd E-glass tape on the inside using unthickened epoxy to wet out the 'glass and a couple of additional applications to fully fill the weave.

G-Flex can be quickly and easily mixed by eye without the need for metering pumps so it can be made up in very small batches which is very convenient for a repair of this type. You can buy a kit which includes 4 oz of resin, 4 oz of hardener, silica powder, mixing cups, gloves and a couple of plastic spatulas for around $25-30. Look at Jamestown Outfitters or NRS.

Although the 'glass I applied was on the inside of the coaming, if you sand the 'glass and thoroughly feather the edges, then completely fill the weave of the 'glass with epoxy, it would be quite smooth.

An alternative to this type of repair is plastic welding. This has become popular with whitewater boaters repairing poly kayaks, C-1s and canoes. A weld will be at most as strong as the original boat, however. I believe that a repair of the type I described will be stronger than the original.

Thanks! will check on the supplies. Appreciate the answers.

have used one of these
poly welders with good results. as long as you have a steady hand and keep the welding iron moving smoothly so as to not burn a hole in the hull, it’s easy to use.