SeaDog

Bonded Washer

$0.30

ColorChoose

SizeChoose

Select color & size to see price

Available in store. Online ordering is paused — call or stop by the shop and we'll set this aside for you.

Ships nationwide · or free in-store pickup

The small one. A #8 bonded washer seals the fastener size used by deck plates and the smaller deck fittings.

Where the #8 Bonded Washer Size Turns Up

Deck plates are the big one. The quarter-turn, screw-out and pop-out plates we stock all take #8 flat-head screws — six or more of them around a flange that sits right where water runs across the deck. Each of those holes is a potential leak, which makes this the size worth buying a pack of.

It also suits smaller pad eyes and any light fitting specified for a #8 screw. For general deck hardware step up to #10, and for foot braces and track hardware to 1/4".

Why a #8 bonded washer Matters on a Kayak

Every deck fitting you bolt on means a hole drilled through the hull. Without a seal, every wave that washes the deck feeds water down the threads into the boat, where it sits, adds weight you then have to pump out, and quietly corrodes the fastener from the inside.

A bonded washer is a stainless washer with a ring of rubber permanently bonded to one face. The metal takes the clamping load; the rubber squashes flat and fills the gap around the screw. Fit it rubber side down against the deck, under the screw head, and snug it until the rubber just bulges — no further. Over-tighten and you extrude the rubber out from under the washer and lose the seal entirely.

Where a #8 Bonded Washer Earns Its Keep

A deck plate flange is wide and flat and it sits in a puddle every time the deck gets wet. Bed the flange in marine sealant, then put a #8 bonded washer under every screw head. If you have ever pulled a deck plate off and found rust tracks running down the inside of the hull from each screw, this is why.

Do not be tempted to over-tighten a ring of small screws to "make sure". Snug each one until the rubber just bulges, working around the circle in stages the way you would a wheel, so the flange pulls down evenly.