Friday, March 28, 2014

Installing Skid Plates - 2

6. Now that you are ready to install the felts, there are two ways to proceed, but one rule about epoxy. If any epoxy fails to cure, it is almost always the failure to properly mix the two parts. Unlike polyester resin, which mixes easily, epoxy needs to be mixed until the molecules of the two parts are adjacent to each other. Whether hand or power mixing, that means at least three minutes of stirring. Here are the two ways to apply the Kevlar felts.
Resin roller.
A - The reason North West had you ready a large piece of cardboard with a plastic cover is for you to saturate the felts on the workbench. To begin with, if you don’t have a resin aerator roller, take scissors and cut off half the length of the paint brush bristles. This will make the bristles stiffer. Lay the felt adjacent to one side of your work surface. Pour a line of resin on the plastic the length of the felt. Lay the felt in the pool and pour another run of resin on top of the felt. Now work the resin over and through the felt to saturate it over its entire surface. If there are any voids, you can probably massage resin into the dry spots from the surrounding surface. Total saturation is essential. If there is any sign of air bubbles, stipple the felt to work the resin through. (Stippling is moving the resin about with short strokes and kneading it through the felt by poking with the end of the bristles. This is why we cut the bristles to half their length.) To avoid a mess, it is better to start with too little resin than too much. You can always brush on a bit more and stipple it through. Once the felt is fully saturated, lay it in place on the canoe and brush and stipple it in place, working from the center out toward the edges and ends. If you have a resin aerator roller, it replaces all of this brushing and stippling. The roller simplifies and improves on the job by making sure there is neither too much nor too little resin in the felt. You can also use an auto-body rubber squeegee to move resin about and into the felt. The greatest advantage of the roller, however, can be seen by examining the edges of the plates where they roll over the curvature of the stem. On Buddy, there is no sign of crumples along the edges of the felts as on the green canoe. This is due to the use of the roller, which works material into place and insures total saturation.

B - This is the method I have used the last 50 years. Brush resin on the area of the hull being covered. Lay the dry felt into the resin and brush a bit more on the top, and roll the resin in with the resin roller. Again, work from the center towards the ends and edges. The aerator blades of the roller insure 100% saturation, thus no bubbles or voids, and also regulate the ration of resin to felt. The roller is also best for working down any puckers in the felt, like around the radius of the stem. If this is the only glassing job you foresee, just brush stipple. If you plan on doing other fiberglass projects, get a resin aerator roller. If you can get one with a metal roller, so much the better. Any epoxy residue may then be burned off with a torch. I have one roller I’ve used for 40 years.

7. Shake some talcum powder on your hands and rub the gloves together. You can now handle other surfaces without spreading sticky resin all over the place. Take paper towel or toilet paper and wipe around the edge of the masking tape to remove any excess or runny residual resin. (Don’t use any paper product after the resin starts to get tacky.) Occasionally touch the resin to see when it is starting to cure. As soon as it reaches a point where it won’t run, remove the paper or plastic skirt we put around the work area to protect the hull. Then remove the masking tape. Never allow the resin to cure with the masking tape still in place. You’ll hate yourself forever. Then, wet a rag with acetone and wipe around the edge of the resin area. This will remove the Magic Marker we used, insure there is no excess resin waiting to run as soon as we turn our backs, and feather the edge so there’s no tape edge in the finished job. Clean all tools with acetone.

8. When the resin in set to a jelly-like state, cut off numerous 12-18” strips of cellophane strapping tape and hang them nearby, like on the edge of the gunwale. Turn under just enough of both ends of the tape to leave a tab you can grab to remove the tape later. Now, holding the tape centered over and perpendicular to the stem, make contact with the center of the tape, and then pull down on both sides while securing the tape to the hull. Continue adding the other strips of tape, overlapping half of the previous strip, and continue until the entire skid plate is covered. You’re done.

9. When the hull epoxy is completely cured, remove the tape. Epoxy will not adhere to the cellophane. The tape further insures total saturation, but more importantly, will cause the epoxy to cure with a gelcoat-smooth finish.



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