Attachment of Plywood floor in Aluminium boat

[Matteo]

I'm intending to put an epoxied marine plywood floor (12-15mm) in my 3.95 tinny. Does anyone have any ideas on fitting the floor without having to use stainless screws? I know there are compounds for dissimilar metals but I'd like to avoid the worry. Would a floor of this type have enough weight to stay down, presumings it is tightly fitted with gussets preventing fore, aft movement?

Your thoughts much appreciated.

[raymond]

You may use PU adhesive to glue the marine plywood direct onto aluminium / steel deck.

raymond

[Buckle]

Due to the natural bending of your hull during operation, for long term reliability I would say you need to secure your floor mechanically. I had a very similar situation a few years ago. In the end, I glued the underfloor to the plywood stingers, with a single skin of glass. Prior to this, I glassed the underside of the marine ply floor and top coated the surface. Then I bonded the floor in (laminated a single strip to the underside of the floor - whilst wet, stuck the floor down), and finally laminated the upper surface of the floor into the hull.

Remember epoxy is a great adhesive. Keep you to be surfaces grease free. Use a little bit of mechanical abrasion before laminating, and you will have a floor which would not delaminate from the hull in rough seas.

Email me if you need further advice.

Buckle

[Thunderhead19]

There are some fantastic products out there for doing just what you want. I personally like a product called Loctite H800, but it's an industrial product, and you might not be able to get ahold of any. Sikaflex 292 is designed for light bonding, and there are various urethane adhesives available that will do just fine.

[Eric Sponberg]

You can try 3M-5200 which has impressive bonding properties, and it remains flexible after cure. 5200 is used to bond hulls and decks together, as well as keels on sailboat hulls. Admittedly, you will also find fasterners in these joints, but it is a universal product in boat building that bonds really well. You could perhaps also use aluminum fasteners in addition to the bonding glue. Aluminum screws can be found in hardware stores.

There is also Plexus adhesive which is used frequently in boat building, without fasteners. It is used in hull-deck joints, as well as bonding bulkheads and floor pans into hulls.

Eric

[J Ralph]

I don't know what you have for stringers, but I had an aluminium skiff that we replaced the floor in,and we used aluminum rivets and they worked surpriseingly well.We epoxied the plywood and bedded it with 5200 fast cure and it's still going strong....good luck

[Arrowmarine]

Sikaflex has NEVER failed for me, no matter what the application. I think the thing that matters most tho, no matter what the adhesive, is that your boards sit down tight to the floor supports. If you are only touching in a few small spots, failure is likely no matter what you use. Hope this helps.
Peace, Joey