I have a Loon 138 and just ordered the rear hatch cover. After i get it cut-out and installed, i’d like to add a bulkhead. Was wondering if anyone has taken on this kind of project. My thoughts are to make a pattern and then use 1/4" Luan and glass it in. My question would be, can glass resin bond to the plastic hull (polylink3, and how would i prep it to do so?
The answer is no
Plastic boats typically use Minicel foam or plastic bulkheads glued in with Lexel or something similar. GOOP adhesives work well for this, though you may need to thin them with toluene or MEK.
I've heard of people having some success using epoxy on polyethylene after cleaning, sanding and "activating" the surface with a torch. However, with the amount of flex that a bulkhead joint will see - such as when you slide over an underwater object - I would go with a more flexible adhesive.
Polyester resin (common fiberglass resin) will not work. I use polyethylene as a release film when making fiberglass panels with polyester resin (or epoxy for that matter) specifically because it doesn't stick.
Some companies weld their plastic bulkheads in place. This can be done at home if you're willing to purchase a plastic welder ($30-$100) and use bulkhead material that's compatible with the hull material.
If you email me, I'll send you some instructions I've written on adding bulkheads.
Minicell Foam. 2 inches thick
From CLC.com worked for me. It’s not the bulkhead flexing that will get you. It’s the floor flexing from you getting in and out of the boat.
Goop and Lexel are both good products but the thing to remember is that your final pattern and bulkhead needs to be a bit proud of the bottom deminsion PLUS you need to cut out “wedges” of the mini-cell about 2 inches off the floor in the fore and aft sidewalls of the material lengthwise across the wall so that the actual thickness of the bulkhead after those wedges have been cut out is less than an inch. This allows the mini-cell bulkhead to “stretch” up and down in that thin area when you step into the boat or any load bearing that causes the floor to flex down and away from the bulkhead.
I learned this from experience with our Loon 138 and after having seen some production mini-cell bulkheads done this way.
BTW, 12 gauge solid wire works well for shaping a pattern to conform to the boats inner demensions. Also, the bulkhead fits extremely well (if you use this size minicell) just aft of the cockpit coaming, in that ridge formed into the deck. It gives you a nice little storage area behind the seat too when the seat is slid all the way back for down-wind performance or just scooting around.