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I just finished installing a front float bag and shaping a Minicel foam slab into a rear bulkhead for my (poly) Dagger Blackwater 10.5. Before I glue the bulkhead in with 3M 5200, should I stick a small coffee stirrer straw through it to act as a small vent? Or how 'bout threading a thin cotton cord through the bulkhead?
My boat has an old style single density rubber "tupperware" rear hatch cover; I imagine the cover would either blow off or just suck in a bit with heat/pressure changes.
Push your tinyest drill bit through it about 2/3rds above the hull floor. This will create a vent for pressure relief but will also stay sealed fro average wetting of things.
Yes, vent it I stick a piece of wire through (typically a bicycle spoke), then insert a piece of the plastic tubing that comes with spray lube cans. That keeps the hole open, but it’s small enough that you’ll get no seepage.
May be overkill. I’d say seal up your bulkhead, and make sure it’s water tight. Then, take it out and swamp it. If the hatch leaks a little, venting the bulkhead’s a moot decision. Of the two rec yaks I’ve had, one sealed well enough to need burping in hot weather (older style). The dual density hatch on the other leaked pretty bad during rolling. If the hatch seals well, you can poke a straigtened coat hanger through the minicel and put a WD40 straw in the hole to keep it open just enough to vent. Like Pat said, try and center the hole up so it’s not underwater if you have to wet exit.
drain plug All 3 of my homemeade bulkheads have 3 in plastic drain plugs. About $4 at hardware store. Or 8 in diam top of plastic pail with top of pail to give you access. Never tried this.
Question I love 5200 sealent I’ve used it on all kinds of things. But how does it react to the poly material a kayak is made of? I know that once the stuff sets up it’s NOT coming off!! But I haven’t used it on a kayak. Most of the time we use aquaseal or a tube of stuff can’t think of the name we get right from Old Town.
3M 5200 I used fast set 5200 on the interior of my boat, but since it’s in a cool basement, it still took about 4 days to cure.
I scuffed up the plastic surface a bit before I applied the 5200 and the bond there is pretty good. In other places, the 5200 just peels right up.
I have the impression that the 5200 bonds to poly about as well as normal caulking does to other materials; sticks pretty good, but can be peeled up with some effort. Since I’m relying on the 5200 for it’s sealant properties rather than adhesive, it’s a good product for the job.
The application will determine what adhesive or sealant is best for the job. If you're worried about damaging the plastic, don't be. Nothing affects polyethylene other than heat.