Wood Treatment Whitewater Raft?

[riverrafter]

I've built a wood floor in the cockpit, wood side-walking platform, and back wood cargo platform for a inflatable river raft. I used marine AB plywood (Fir). I'm seeking some suggestions on what to treat/coat the wood with:


The wood will be getting wet all the time being a whitewater rig.
I'm more interested in something that will encapsulate & strengthen the wood and prevent wood splinters, because it's near Hypalon Rubber. This is the most important!
Wood will be flexing constantly being in a rough whitewater environment, so something flexible.
The wood will be exposed to a lot of sun.

Also, I have a few small voids that need to be filled in. Would you use a wood putty or something else?

Thanks!

[Thorne]

Fir ply will require epoxy over fiberglass or other fabric like Xynole. Some epoxies are rated as being more flexible than others, but I'm not familiar with that type.

Once covered with epoxy and cloth, the flexibility of the panels will have to be created mechanically if the solid pieces don't flex enough -- meaning cut into sections joined by hinges or fabric/rubber panels.

Cover the edges with thickened epoxy (cabosil is a good thickener) over the cloth to minimize potential abrasion, and add carbon powder if possible for additional slickness. This mix will also work for filling the voids or gaps you mention above.

Use either a very high UV-rated varnish or good paint over the epoxy. Do yourself a favor and get a non-blushing epoxy, and let it cure fully before painting or varnishing.

[riverrafter]

What are my options if I don't want to use fabric?

[Thorne]

None. The epoxy will crack and fall off if the ply flexes very much, plus the coating of epoxy won't be very thick. Water gets in through the cracks and under the epoxy coating.

You could treat some of the floorboards as replaceable, and just paint the top and bottom. For the edges seal and coat with thickened epoxy. But marine ply will check and you'll have to keep a very sharp eye out for splinters and abrasion of the raft material.

Other options include using thinner marine ply and just using tape (fabric strips) on the edges, or using some artificial material for floorboards.

Others may know more, this is just my opinion!

[Gary E]

Make sure it has a real big radius where it could poke the raft.

Any of the Deck Coatings that you'd use on the deck at home..
Slather it on, spray it on, mop it on.. soak it... soak it good.

[Bob Smalser]

What are my options if I don't want to use fabric?

I've done a couple utility decks on rafts similar to yours. Without fabric your plywood won't last very long in hard use. It'll eventually splinter and puncture your tubes. The trick is to use an easy-to-use fabric.

1) Round the corners and radius the edges to a bullnose using a router. Predill all the mounting holes oversize so you can coat the insides with epoxy.

2) Fill the voids with epoxy and fairing compound like West System #105 resin with #209 summer hardener and #407 low density filler. Follow the instructions. Sands easily.

3) Coat with epoxy and cover on both sides and the edges with a lightweight, 4oz fiberglass fabric. It's cheap, feathers nicely, is very easy to smooth around corners, and unlike some heavier fabrics, is easy to repair when the time comes. Insure the epoxy fills the weave.

4) Sand lightly after curing and paint both sides with primer followed by the exterior paint of your choice. If you skip the primer, sand with coarse paper.

5) Sand or Scotchbrite the top lightly and apply a second coat of paint thickly.

6) Sprinkle a heavy coat of table salt into the wet paint. After the paint dries, hose it off and you have a nonskid surface that'll last a long time.

[ShagRock]

Posted by Bob Smalser:
Sprinkle a heavy coat of table salt into the wet paint. After the paint dries, hose it off and you have a nonskid surface that'll last a long time.That's a neat solution! Will the NaCl deteriorate at the same rate as the paint?

[Bob Smalser]

That's a neat solution! Will the NaCl deteriorate at the same rate as the paint?

The table salt will disappear completely under the hose, leaving a pock-marked surface. Salt doesn't affect the paint.

Rock salt leaves too coarse a surface.

You can also use sugar, but when the ants find it you'll regret that choice.

[Chip-skiff]

Next time, try this stuff:

http://farm4.static.flickr.com/3322/3262048996_9e919f33fb.jpg?v=0

PolyMax kennel/brooder floor from <www.TekSupply.com>. Recycled plastic, made in Canada. Non-skid, drains instantly, doesn't absorb water, doesn't rot, UV resistant. Attached to the frame with hoseclamps sheathed in 3/8" id/1/2 od plastic tubing for safety, and foam pipe insulation cable-tied along the leading edge.

http://farm4.static.flickr.com/3450/3254923510_8162dd320f.jpg?v=0

This is a split deck for a dog (passenger sits on the cooler), with aluminum tubing support on the inner edges.

http://farm4.static.flickr.com/3377/3421831876_2c35d7f48b.jpg?v=0

Here's a playcat with a PolyMax floor, supported with aluminum angle and straps. I (225 lb) can stand on it, no sweat. The cat tubes are from Jack's Plastic Welding. I build the frames.

My sailing skiff is wood, but I don't use wood decks on whitewater boats anymore.

[riverrafter]

Chip,

You're a man of many talents, I was thinking about sending you a PM on the MB about this. I thought I would see what the wood boat experts had to say on this forum. I'm mostly concerned with the cockpit floor and rear beaver tail. Both will be loaded with gear, groovers, and water jugs. I'm try to prevent any possible wood splinters with the edges of the boards near the side tubes.

I'll probably go to poly for my side decks eventually, but not sure if hanging from straps the poly for a larger floor area in a regular raft would be strong enough.

For the time being I need to use my marine plywood that is cut/router and fitted. What are your suggestions?

FYI, I like your new dog platform on the new frame. My dog just gets to use the old Paco on the cooler.

[Chip-skiff]

As usual, Smalser's advice seems pretty good: marine epoxy with a 'coating' hardener, de-blush and let cure, then apply a few coats of decent spar varnish and some non-skid stuff. I used coarse sand on my old oartower platforms and the result was flesh-ripping. Horrible to kneel on, so use a fine grit or table salt. (What about sprinkling micro-balloon filler?)

On my sole remaining wood deckboard (mostly covered by a cushion or pad) I use peel & stick 3M tape (the grey sort, which is rubbery rather than the black sort which is sandpapery). For refinishing, it comes off pretty easily with a heat gun (or hairdryer).

[Simmons18]

A good solution would be to coat all surfaces with poly "truck bed liner" after the epoxy sealer. The top of the line do it yourself concoctions are good enough if you get it thick. Cabellas sells some for decks available in several colors.
Good luck controlling that raft.
Simmons 18