Finishing Plywood Drop Boards

[Rich6705]

Good afternoon. I just purchased an O'Day sailboat and the companionway hatch boards are rotting. They are made of plywood and look like they have been stained first then sealed with epoxy.

What is the proper way to finish the plywood? I was thinking about using a penetrating epoxy sealer first then covering with Cetol or Varnish. Will that keep the water from getting in through the ends of the plywood? Are there other options?

 

[jssailem]

Rich. Good idea. Choice of plywood is important. Marine grade will be more expensive but tighter glued, fewer glue pockets. Rather than a "sealer" I have used straight epoxy. Soaked the edges of the boards. Have to work fast applying the product while it is in its liquid state. Once it kicks it is all over with that batch. Working quickly you can apply a fair amount to the wood as it soaks the epoxy up. Then I epoxy the surface front and back. Let dry. Remember to clean the Amine Blush before sanding. -- thoroughly washing the cured epoxy with clean warm water, all-purpose soap, and a stiff brush or Scotch-Brite™ pad. The amine blush is water soluble therefore the only way to completely remove this is by following the instructions above. You will want to clean the amine blush off of the epoxy before sanding as well. If you begin to sand before removing the amine blush, you may sand the blush deeper into the surface making it much harder to remove. Then sand and apply a second coat. Once the epoxy is cured. Clean and apply varnish.
You'll have a nice set of boards. But they will not be a do and forget project. You'll need to annually inspect and freshen the varnish from time to time.

The epoxy method makes the project last much longer than straight varnish/cetol to bare wood. The Varnish gives the epoxy/plywood a needed UV protector.

 

[rgranger]

Plywood would not be my first choice unless the ends are free of voids. A good piece of oak or pine would be my first choice. You can buy 4" wide oak or pine boards at Lowes. They are usually found in the area with the trim strips and dowel rods. Cut to length, and bevel the edges that will touch when in place. You want the bevel to be angling in at the top of each board so rain water would have to crawl "up-hill" and can't get in at the cracks. Sand very smooth and then put six to eight coats of marine varnish on them. Do not use polyurethane on any wood exposed to sunshine. Epoxy is also not a great choice since it is very easily oxidized by UV exposure.

 

[KD3PC]

key with plywood is to get marine grade, exterior glued, or epoxy/seal it your self.

I like the hardwood option or even darkened lexan. much longer wear with less maintenance.

 

[rgranger]

I guess Trex would also be a good option. It would look 90% as nice as real wood with 100% less maintenance. You can also get really wide deck planks in Trex so you could make your companionway with fewer boards. On my Hunter I have alternating hardwood and lexan. It looks nice and it lets a little sun in. I've never cut lexan before. I'm guessing you would need a really sharp blade to get the edges to look correct.

 

[Charlie Jones s/v Tehani]

I guess Trex would also be a good option. It would look 90% as nice as real wood with 100% less maintenance. You can also get really wide deck planks in Trex so you could make your companionway with fewer boards. On my Hunter I have alternating hardwood and lexan. It looks nice and it lets a little sun in. I've never cut lexan before. I'm guessing you would need a really sharp blade to get the edges to look correct.
View attachment 132202

Lexan cuts quite easily with an table saw, band saw or circular saw

 

[jssailem]

Couple of ways I understand. Clean sharp blade - Band saw. (be sure to tape the lexan first). Saber saw, or fine toothed table saw. The tape helps to reduce chipping and maintains a clean line to cut.

 

[rgranger]

Lexan cuts quite easily with an table saw, band saw or circular saw

That is good to know. Thnx.

 

[Ralph Johnstone]

I can only speak for System Three with which I have had outstanding success, although I suspect all epoxies are the same formula today. Take a look at their bible:

https://cdn.shopify.com/s/files/1/1000/1906/files/The_Epoxy_Book.pdf?1285685231865784556

........ and you'll see that such things as amine blush are from a previous generation of epoxies. System Three can be thinned with up to 10% lacquer thinner for a primer which makes it like water and takes hours to cure. It still cures to a hard consistency. I usually apply about five coats. Just remember to finish with varnish (2-3 coats) for UV protection and it will last many years. Follow the book religiously and you'll get something like this:

The stairs are covered with glass cloth for wear resistance and the rail seat has not been revarnished for many years.

 

[jssailem]

Ralph. Nice stairs. Who made them. Like there design.

 

[Ralph Johnstone]

Nice stairs. Who made them.

The treads are the original varnished (about 1/2 coat) teak stock (1") that came with the new boat. They were starting to look pretty shopworn after a few thousand gritty little feet pounding up and down over five years. I took them off and dadoed out the original grooves they used for non slip and filled them with black epoxy. I've always looked back and thought I should have made them holly in colour. I have 20/20 hindsight. Glassed them for wear resistance and covered with five coats of epoxy resin. Still look like wet varnish today and the gritty little feet are now teenage girls so not quite as much wear and tear as before.

 

[capta]

You might want to consider Starboard. Zero maintenance and plenty strong. It comes in a variety of colors, as well. Personally, I prefer a door, as below, but that might not work on a 25 footer.

 

[jssailem]

Nice Capta.
Do you have pictures of your door from other angles so I can see how it was constructed?

 

[capta]

Nice Capta.
Do you have pictures of your door from other angles so I can see how it was constructed?

Soon. A bit busy, sorry.

 

[jssailem]

No problem. Looking forward when you get the time.

 

[agprice22]

Do not bother with plywood. Make them from King Starboard, or make nice plexi opening doors:

 

[capta]

Soon. A bit busy, sorry.

Finally got you a couple of pics. Sorry for the wait. If they don't give you what you need, let me know.

Sorry, can't figure out why it duplicated a picture.

 

[jssailem]

can't figure out why it duplicated a picture

You were just a bit quick with the mouse trigger. I heard it happens when one is excited or it is the first time.

 

[capta]

You were just a bit quick with the mouse trigger. I heard it happens when one is excited or it is the first time.

Rats

 

[rgranger]

I like how you did the latches. Is it lockable?