Rubbing alcohol has oil in - keep it away from epoxy unless you want to clean it later. Call CLC or email your epoxy manufacturer and ask about a solvent or use denatured alcohol (virgin, not reprocessed). Also ask about how to thin the epoxy so it will flow into your crack better. A solvent in the epoxy has to evaporate; if it does so in the crack, what replaces it? Air? Maybe heating the epoxy slightly before pouring it in. Vibrating the hull to help the epoxy displace air. Heating the hull to thin the epoxy once it is inside the hull. Or maybe someone can suggest another gap-filling fluid to seal your crack. For example, one of the various cyanoacrylates used in building model aircraft and in some of the CLC classes to speed hull assembly.
If you use a CA, please read the safety instructions. Pour a small amount of medium CA into the upturned hull. Use a screwdriver on the end of a stick to herd the CA toward the crack (don't get the screwdriver stuck). Watch for the CA to come out the bow hole - means you have good penetration. If you still have a crack after it cures, repeat. The CA might attack your finish so be careful.
Again, a call to CLC or one of the Schade brothers might provide more insight or options for your repair. Good luck.
Since I can now see the source of the leak I don't think i need to use any solvent to trace it any further. I think I will try and plug it from both ends. CA or thinned epoxy thru the hatch and then fill the hull hole and redrill.
Now I'm starting to ponder why this happened. Could it be heat build up in the sealed compartment? I have been leaving the boat on my patio which can get quite warm during the day...and it's still early in the season.
It probably wasn't exposure to the elements that caused the crack. Check the aft end pour. If no crack, the bow crack probably occured when the epoxy heated, then cooled, during cure. You did the two pours at different times, so the bow might have gotten hotter than the stern, or it was cooler outside for the stern pour, or ...
If you are worried about heat cycling on the patio, loosen the hatches some when stored. Just remember to retighten before you travel or paddle. The worst heat cycling occurs when you take your yak off your car, where it's been heating up in the sun, then pop it into some cold water. The air inside the compartments cools quickly and shrinks slightly, pulling a small vacuum if the hatches seal real good. Most people don't think or worry about it, just wonder why their hatches are harder to open every once in a while.
There is a trick I've used several times to get glue through small cracks in wood. Apply the glue, epoxy, or whatever else you're trying in a small space, put the nozzle of your shop vacuum on the opposite side and turn it on. It sure beats depending on gravity, capillary action or blowing it in with compressed
Sorry to hear about your kayak Daniel. I would be careful about using CA (super glue) it usually is not compatible with epoxy. Give MAS a call 856-303-9245 Toll-free: 888-627-3769 or 800 398-7556. MAS are great you always get a person or they will call you back. Depending on access you could try a long aircraft drill bit to make a few holes in the cracked area to help get the epoxy to flow in.
When I did my end pours I did two or three pours with micro balloons and a cardboard dam to minimize heat build up. The only problem with that is I did not get a cool photo of my kayak leaning on my house.
I'm just starting my build, so the following is NOT based on experience. However, the crack sure doesn't seem to be a structural issue, so why bother with trying to fill it with epoxy or CA? It seems like good old marine goop, aquaseal or similar silicon-based sealant/adhesive would do the trick. If you go the CA route, you can get a small tube of "thick" CA from any hobby shop that sells RC Airplane kits. CA (unlike boat building) is something I have a lot of experience with, and given a long enough cure time, I've never had bonding issues against an eopxy substrate, and you can always use accelerator. By the way, you can thicken CA with carbosil if necessary. Anyhow, just some random thoughts - best of luck, and you sure made a beautiful boat.
-Zach
Geez, Dana, even your end pours are gorgeous! I may give MAS a call later. I sent Nick S a note on Facebook. I'll see what he has to say too.
C.Dubois, I like the vacuum idea. I just bought a vac/dust collector with variable suction and that might be just the thing. I just have to be careful not to get epoxy in the hose.
Thanks to everyone for all your comments and advice. This forum is great!
Dan
Solution, I hope...
I propped the boat on a step ladder in my basement as high as possible. Since the crack is towards the sheer clamp I put the deck down. I sanded the grab loop hole with 80 grit to remove the varnish and clean it up a bit. I then took some clear packing tape and covered one side of the hole. The other side I covered except for a small hole near the top. Instead of a vacuum cleaner I brought home my handheld vacuum pump from work. I used this with a small suction cup adapter. When I did a trial suck it was obvious by the sound that the crack went all the way thru. I then mixed about 4 oz of epoxy, reached in the hatch and dumped it as close to the bow as possible. I waited a few minutes and started to see some epoxy flowing into the hole. I applied a small amount of vacuum to speed it up a bit. As the epoxy reached the top of the hole I tapped the tape on both sides to get a few bubbles out. Then when the epoxy started to ooze from the small hole in the tape I applied more tape and sealed it up.
Now time for a drink. Cheers all!
Tomorrow I'll redrill the grab loop hole and I'll be back on the water Friday (I hope).
Dan
Congrats, Dan! And thanks for posting your solution. Happy paddling, soon.