I have a Mohawk Probe 12 II that has a spot (3-4" diam.) that has delaminated . It is right under my saddle. No water has reached the inner core.
Now several years ago I did a similar repair on a Whitesell. My problem was the Kevlar cloth I used seemed to be too "coarse" to work with, i.e. the weave count (or whatever term one would use for that spec) appeared to be too low.
Any suggstions on which Kevlar specs to use for this repair and where to get it. Thanks for any help.
I have had very good luck using the kevlar felt that comes with crunch pad kits. There are two sizes available--"whitewater" and "expedition". The expedition size is almost twice as long as the standard size. Both kits come with 2 part epoxy . Follow the directions. One additional thing is to stretch(and tape to the boat)clear handiwrap over the repair.Work out the air bubbles very carefully. This will make the repair smooth . The kevlar felt can be used on the inside or the outside of the boat--or both sides if necessary. You can also add color pigment to the epoxy to match the color of the royalex.
Nantahala Outdoor center and most mail order catalogs list the crunch pad kits for sale.
Roger, you can reach Sweet Composites from this board. I don't think your problem was the cloth you used. More likely, how you used it. You need at least three layers, concentric, with the LARGEST layer going on first. You must either prepare the vinyl thoroughly, or scrape down to the ABS. The biggest patch layer should extend past the fault by at least an inch. The smaller layers should be, successively, about 1/4 inch smaller.
If you have delamination, then consider trying to find a dental syringe, the kind used to rinse out gum holes after a tooth extraction. With such a syringe, you can make up a mixture of epoxy and microbubbles, and after drilling a small hole, inject it under the delaminated portion. You should consider alternatives such as injecting Seamgrip, which is a polyurethane.
Layers of Kevlar cloth, or layers of S-glass, also available from johnrsweet.com, are FAR superior to Kevlar felt. NO felt can match woven cloth, or alternating layers of straight fibers, for strength in a laminate.
If I understand your problem correctly, the core has delamated and a void of air is inside your royalex. If this is true, adding glass/kevlar etc to the out side of the boat will not hold up. The max shear is in the middle of the royalex and your problem is going to get worse. This is the hardest repair to make I believe.. The only thing Ive had work is to drill a small hole in one side (inside if possible) half way through to the delaminated area, and use a syringe available form Sweet, and inject epoxy into the delamited area.
try dissolving abs pipe in acetone, then painting it onto exposed foam in very thin coats. let it dry and harden between coats. bombproof stuff and cheap too!
note:very toxic fumes!
What about using in acetone dissolved polyvinyl chloride (PVC)? Should be the same Material as the outer layer of the boat and it is more UV stable, isn't it?
I'm going to try to dissolve some PVC plastic film today and use it as soon as it's ready. I'm curious if it'll work.
I've had good results (good enough to run the Middle Fork Salmon with it) by injecting a polyurethane glue such as "Gorilla Glue". Sometimes I cut away the ABS over the worst of the delam and fill with the polyurethane. Top it off (after the glue cures) with Shoe Goo or one of the other Goop products such as Marine Goop from the Eclectics folks. One beauty of the polyurethane glues is that they cure by taking up moisture so it is not necessary to go to heroics in drying the area to be repaired beforehand.
Update on the repair: I carefully cut out the delaminated part(turned out to be about 4'x5" in size) leaving a slightly beveled edge going out to in. I filled this with JB weld to level even with the outside. I then cut two oval shaped patches (first to cover the JB plus extra and second larger than first) making sure I had enough overlap.
As I applied the patches, I used saran wrap and a brayer to insure saturation of the fabric with liquid, effectively squegeeing (sp?) out any excessive adhesive. I wiped away the excess with acetone. After 24 hours, I took a Dremel and slightly beveled the edges (very light touch here) and then dabbed a bit of adhesive on the areas that were abraided.
Two days later, I had it on the rivers. Took several shots in the area but the patch seems to have held rather well!
In the process of doing the repair, I found one more smaller delaminated area. Will probably drill small hole into center of area and inject one of the adhesives suggested above.
Many thanks for the suggestions to my request. Got some idea about an ole Whitesell that needs to make-over!
BTW, headed back east on the 22nd of this month to the Ocoee/Nanty area. If you see a red Cherokee with a purple Mohawk on top, it'll be me.
bushpaddler wrote:What about using in acetone dissolved polyvinyl chloride (PVC)? Should be the same Material as the outer layer of the boat and it is more UV stable, isn't it?
I'm going to try to dissolve some PVC plastic film today and use it as soon as it's ready. I'm curious if it'll work.
Florian
update:
Tried to dissolve PVC in acetone. I thought Vinyl should be dissolvable in ketones (which acetone is) but my PVC doesn't know that and only gets flimsy and wobbly but not solved. Seems like I slept in my chemistry class. Got some uncoloured ABS Granulate now from a an injection-molding guy and start solving this.
So much for that...
I definitely wouldn't recommend this but when you're desperate anything is possible.
Earlier this month my canoe was being transported to the put-in of the Grand Canyon when the front of the canoe broke loose and it was dragged behind the trailer for a mile or more. The bottom of the canoe was worn almost through the entire thickness of the foam. The best that we were able to do is buy some polyester resin and glass mat to repair the bottom. I didn't give it much of a chance of holding up for the entire 18 days but I had no other choice. The Grand Canyon doesn't have very many rocks to bang into so the patch held up just fine. The patch worked so well that I'm going to use the same canoe for another Grand Canyon trip in September.
Sorry, I don't have any Grand Canyon open boat videos except for a few that were taken during the early 90s.
I've been using the Outrage-X that I have stashed in Flagstaff. It's a great Grand Canyon boat due to the soft chines and rocker. I've paddled a Caption a few times but the swirlies and whirpools would catch the edges and flip me over every once in awhile. I moved the Caption to Boise and I'm sticking with the Outrage-X or an Outrage for the Grand.
. It is right under my saddle. No water has reached the inner core. 
. I'm sure you can guess what it looked like 20 seconds later 
I moved the Caption to Boise and I'm sticking with the Outrage-X or an Outrage for the Grand.