PDA

View Full Version : Need advice on finishing



hoffy
04-16-2007, 01:56 PM
At stage of completion where I need advice as to "best"/ "most economical"/ "easy to apply" finish to an Elver that will be sailed in fresh H2O. Bottom is marine ply; sides are cedar strips;decking is marine ply. What is suggested for interior finish? For various reasons I'd like to stay away from e-poxy. Any thoughts on using Deks Olje#1 on the interior . If I want a clear finish on the cedar what's best ? Varnish? Polyurethane? Other?

Looking forward to your replys, Don H

Thorne
04-16-2007, 02:39 PM
Interior meaning inside the cabin and belowdeck, or the cockpit also? In other words, exposed to the sun and elements or not?

Well worth the $8 to pick up last month's copy of _Classic Boat_ from the UK -- they have results from a 3.5 year test of various finishes -- the oil ones didn't do too well, with Le Tonk doing best.

Most economical? Probably an inexpensive varnish, thinned for the first coat and thick for the rest. Least amount of work three years from now? Probably CPES with varnish over it...or paint.

Brian Palmer
04-16-2007, 03:09 PM
Mine is at least 20 years old and was purchsed used. It was sealed inside and out with epoxy, and I am not convinced that it has helped prolong it's longevity.

I've just spent another weekend digging rot out of various solid wood and plywood members and gluing in dutchmen with thickened epoxy. Not very satisfying. It would be much nicer replacing cedar and oak fastened with bronze screws and bolts and caulked with cotton.

My theory, based on my empirical observations, is that if the epoxy coating is ever penetrated, water will enter the penetration, no matter how small, and slowly soak through the wood with nowhere to go.

I've pulled off several members from the cockpit area that have a nice firm epoxy coating. But, you can poke your finger through the epoxy and pull out soggy rotten wood fibers from inside the crispy epoxy coating. Henceforth this should be formally known in boat repair circles as the "crunchy outside, chewy inside" disease.

This has happened to what appear to be fir plywood bottom panels, a solid yellow pine inner keel (maybe even pressure treated), solid white pine floor boards, and solid fir frames.

Fortunately, the cedar planking is in good shape. Other parts that are made of white oak also appear to be in good shape.

I'd be tempted to finish the outside of the planking, decks, and cabin with epoxy for abrasion resistance, if they are not already covered in glass, and then coat the inside with traditional paint and varnish. Some folks here think that the traditional coatings allow the wood to "breath" and allow moisture to escape so it doesn't build up over time.

Also, I would install garboard drain plugs in the bottom of your boat. Put one in each corner and on each side of the inner keel at the forward end of the cockpit (four total). That way, any rain water that gets in the boat can drain out if the bow is tilted down a bit, even if the boat is not level side-to-side. Part of the problem with my boat is that it was neglected for several years and may have had standing water in the cockpit for a while.

Finally, make sure the area behind the after bulkhead is well ventilated and can drain to the cockpit, since rainwater can get in through the mizzen mast hole. This last weekend's excavations focussed on rotten wood in this area in particular.

Good luck with your Elver. I really enjoy sailing mine.

-- Brian

hoffy
04-18-2007, 07:07 PM
Brian,

Thanks for your info. I agree on the epoxy. Any other ideas, keep them coming.
Don

hoffy
04-18-2007, 07:13 PM
Thorne,
Thanks for your reply.I'm thinking below deck[cabin] and cockpit. Where would one pick up "Classic Boat"? Web site? Don

Audioten
04-19-2007, 04:01 PM
I'm just about to start building Ken Bassett's Rascal. And i've been told not to use epoxy on the inside. What shoud i do. Paint og epoxy seal the inside of the boat?

capt jake
04-19-2007, 05:55 PM
I'm just about to start building Ken Bassett's Rascal. And i've been told not to use epoxy on the inside. What shoud i do. Paint og epoxy seal the inside of the boat?

I think that is all wrong. I would seal it with epoxy and then paint or varnish to your liking. Why would one seal the outside and not the inside of a modern constructed boat?

Thorne
04-19-2007, 06:32 PM
So that water that gets into the wood can get back out again?

Some boats are sealed on the outside with epoxy or many layers of sealer and paint, but left painted or just stained on the inside.

A lot depends on whether the boat will live in the water or not, or if you expect water to be standing inside the bilge for long periods of time.

Think of it this way - take a damp sock to represent the wet wood. It can get wet due to a crack in the seal coat (paint or epoxy) or just from being in the water for long periods of time.

1. Put it in a plastic baggie and seal it -- watch the water gather on the inside of the plastic. Leave for a week and PHEW!

2. Put it ON a plastic baggie -- the water will gather underneath but will wick into the air gradually, more or less.

Not saying that this applies to all boats under all conditions. But some boats seem to operate best with a waterproof seal on the outside, and a coating that breathes a bit on the inside.

capt jake
04-19-2007, 06:41 PM
So that water that gets into the wood can get back out again?

Some boats are sealed on the outside with epoxy or many layers of sealer and paint, but left painted or just stained on the inside.

A lot depends on whether the boat will live in the water or not, or if you expect water to be standing inside the bilge for long periods of time.

Think of it this way - take a damp sock to represent the wet wood. It can get wet due to a crack in the seal coat (paint or epoxy) or just from being in the water for long periods of time.

1. Put it in a plastic baggie and seal it -- watch the water gather on the inside of the plastic. Leave for a week and PHEW!

2. Put it ON a plastic baggie -- the water will gather underneath but will wick into the air gradually, more or less.

Not saying that this applies to all boats under all conditions. But some boats seem to operate best with a waterproof seal on the outside, and a coating that breathes a bit on the inside.

I disagree in this instance, but what ever. ;) There is no need to even let water into the wood on modern construction. For instance, I just visited Devlin's shop today to take a look at a Sockeye 45. It is obviously going to live in the water. Modern construction and it is sealed inside and out to prevent water intrusion.

Todd Bradshaw
04-19-2007, 07:41 PM
Sealing the outside and leaving the inside "breathable" (or whatever term you want to use for soaking up water) on many modern wood/epoxy constructions is also contrary to the research, teachings and real-world experience of most of the professional builders who developed the techniques - like Gougeon Brothers. Sorry Thorne, but the wet sock example doesn't fly and assuming that the moisture is just going to back-up and exit through the non-sealed side without doing damage is a mistake.

It should be noted however, that builders like Gougeon are very careful about not generally incorporating big hunks of solid wood into their constructions. There is a limit to the ability of an epoxy coating to stabilize solid timber pieces, so structural members are usually laminates of some sort and the biggest bits of solid, non-laminated timber in the boat may well be a few 3/4"x3/4" stringers, or similar. Frames, bulkheads and such are usually multi-piece constructions which have been assembled and epoxy sealed on the bench and then installed to make sure the construction and sealing are high-quality workmanship, rather than somebody working upside down with a paint brush and resin, jammed down inside the hull somewhere.

So far, these boats and their construction have a track record that's up to around 25-30 years at the moment, and for the most part doing well. However, if you start incorporating hunks of solid wood the size of 2x4's or building-in nooks and crannies that you can't properly seal, you may eventually have serious problems caused by expanding/contracting/moving wood, broken seals, leakage and rot.

Whether or not you ever intend to build an epoxy-sealed hull, the Gougeon Brothers book is worth reading if you're using epoxy. You'll find that one of the main themes throughout the book is to start with dry wood in managable, sealable thickness, seal it properly and design and build with the intention of making sure that it stays that way.