Terry Newcombe wrote:
Phew, I'm glad you told me to apply the release fabric after you had peeled off the tape/newspaper, Mike, as I would have done it before. But doesn't pressing or rolling over the release fabric squish the expanded Dynel (good) and push surplus epoxy out onto my Kevlar canoe surface (bad)? I'm using G/flex 650.
Other people do it the other way, I’m just not sure how they manage it?
If I leave the perimeter tape on, lay and roller compress the peel ply over the dripping epoxied saturated Dynel, won’t I epoxy the tape to the hull? Does that tape pull cleanly, or do I have to slice pieces of it out with a razor blade the next morning?
Maybe this is done using “green pull” (nylon) peel ply, peeled off (you hope) a few hours after the epoxy goes on? I am not fond of that just in time green pull guessing game. “HELP, somebody come hold the canoe, I need both hands!”
I love release treated peel ply; after some shop hours of cleaning, prep work and taping/papering I’m ready to lay some epoxy, cloth and peel ply and then walk away ‘’til the big reveal the next morning.
I dunno what I dunno; my way works for me and I have become seriously fast and proficient at taping and papering prep work, so efficient that I don’t mind doing it twice, once for epoxy and once for paint. Skillled enough with tape that I probably get a job with Earl Scheib.
https://www.youtube.com/watch?v=PtjdHaMeiiQTape pullled off and peel ply compressed it does leave the epoxy edge a little fuzzy, but if the epoxy/graphite powder has stopped dripping before the peel ply is compressed it won’t smush out that far, even rolling down the edges.
I just wait a week, clean it, retape it and paint it with cheap black Rustoleum enamel for some UV protection and nice, neat straight lines.
Terry Newcombe wrote:
Thanks for the link to your well-photo'ed skid plate report, Mike. I see why you suggested my 2" width be widened; your skid plate is triangular but I was thinking it should be a replacement for the retail kevlar skid plates, which are strips only 1.5" wide at the bow and maybe 3" at the 'under the seat' end. Is your base width (8"?) because this is a whitewater canoe?
Once the stems are scratched up a bit I have a target area to overlap in length/width/shape. I have installed some skid plates on minor/early scratches, kinda knowing where the stem shapes and typical use will merit protection.
I have a half dozen differently shaped skid plates on different use and stem-shape canoes. Great broad triangles on wide boats that get bow driven onto sandy beaches and shallows. Two inch wide skid plates on some sharp stemmed wetfoot lake boats.
Vee bottoms and decked hulls tend to be longer ands skinnier; I would pay the price for seamed-edge 2 or 3 inch wide Dynel tape. Someday.
Some DIY skid plates match the size and shape of Old Town (and others) kevlar felt skid plate kits. OT’s, which were neatly rounded on both ends, were 3” wide at the narrow end, 8” wide at the fat end and 36” long. Too much felt for most applications; even when I regrettably used them I often cut them down to more appropriate lengths. Lengths plural; bow and stern are sometimes wear-area different.
Terry Newcombe wrote:
Your example also surprised me because it doesn't run up the front 'bumper' of the bow to just above the water line, as I thought most Kevlar skid plates do. I agree with the easier taping, but don't you need that front bumper?
The taping, and especially the worse results complex-curve form fitting of a woven material along a curve is a PITA. Making a keel line slice for an inch or two down the narrow end of the Dynel helps accommodate some recurve without puckering. Rolled down (repeatedly) under peel ply even the wrinklepuckerfolds mostly disappear. But you don’t need a 3 foot long bulbous teardrop skid plate on every stem.
I have some canoes with the skid plate a few inches above the cutwater. And yeah, I have mistimed some rocky eddy and smacked a RX bow into a vertical rock. Oops, I try not to do that, even in canoes appropriate to WW.
Some of the old kevlar felt skid plate instructions read something like “Measure down five inches from the tip of the deck plate and begin the skid plate there”. On some rec canoes with classic re-curved stems that put a comical lotta fugly kev felt sticking up out of the water.
One thing with a single layer rolled-compressed Dynel and peel ply skid plate – It turns out so hull-flush and smooth that, if you mis-guessed the size, you could (years later) install a bigger/wider skid plate overtop and it would still be flush. And double Dynel layered in the center.
Terry Newcombe wrote:
Hah, I didn't even know West System sold a graphite powder. I had been thinking of just using a bit of some 10 year old graphite powder meant as a lock lubricant. Do you think a half-teaspoon of that is better than not using any at all?
I have zero idea how 10 year old graphite powder lock lubricant would work with epoxy. I do like the graphite black; if that stuff is a fly-away dry powder maybe lay out a test patch of Dynel scrap, epoxy and that graphite powder and see how it turns out.
About “just a bit”, that depends on the amount of epoxy mixed in each batch. I’m in the “Can-always-pump-another” party, and mix couple or three ounces at a time on something like skid plates. I hate wasting epoxy left in the pot, and try to have some secondary use prepped and waiting, even if that if just sealing wood sawhorse feet
I put a teeny dab of black color agent pigment in the epoxy, just ‘cause I have some, and something under 10% by volume graphite powder. The graphite powder adds far more and deeper dark than the dab of pigment, and closer to 10% gets thickened less G/flex wasteful drippy down the tape and paper, and graphite slippery as hell, which can’t hurt for sliding over unseen oops.
Blahblahblahblahblah. A thoughtful material, well executed and well designed skid plate can be a thing of beauty instead of an ugly pimple plastered on the stem