Thread: varnish

I would use a few coats of epoxy as a "primer" and use UV resistant Yacht varnish on top of that.
Epoxy has a much better bondage with wood than original varnish. It also gives a great waterproof barrier. On top of that you can use traditional varnish ( that will last longer since the base coat is better quality ) or a high-tech 2-pot varnish ( that will last even longer, but is more difficult to use ) .
Both wil still give that traditional look.

This is not a proffesional advice, just my personal experience.

I would not give an under coat of epoxy, it's just wasting the stuff and making a lot more work for you in the future. Epoxy is only effective as a coating, if you encapsulate the piece. If you are not encapsulating, then you might as well skip the whole step and more straight to finish, which could be varnish or polyurethane.

a high-tech 2-pot varnish

I also would not use a two part polyurethane (which is what he was describing, it's not a varnish) as it's too rigid for you application and will likely crack along obvious locations. This type of finish, though very durable, just doesn't have the flexibility necessary for your application.

What you want is real alkyd spar varnish, preferably with the highest UV inhibitors available. I don't know what that is in your country, so hopefully Mik or some one will bounce in and offer up the local specialties.

You could use a single part polyurethane, which isn't as rigid as two part types, but is more so then regular varnish. This boat can tolerate a single part poly.

There's no easy way around natural finishes on wood in the marine environment. Without question, it's the hardest type of finish to keep, so be ready for the work if you make this decision.

That sounds OK to me too.

PAR rocks.

MIK

Thank you all.If i can upload a photo of my FD i will,just to show you the job i've got..Looks like i'm using spar varnish.

PAR rocks? Well, sometimes, but I'm more of a jazz guy.

Please post a picture of your Dutchman. Spar varnish is a good choice, though as mentioned a good quality single part spar urethane will also work and speed things up too (faster drying times). On either clear coat, if going over raw wood for the first time, thin the varnish or urthane with mineral spirits about 15% - 20%. This will help it "grab" the wood fibers and form a good base for subsequent coats. Raw wood to a reasonably protected finish is at least 6 coats and better if there are more.

Quite interesting discussion about varnishing, but if you want to have less "sanding and varnishing every year" you really need to consider using epoxy on bare wood and use a high-tech UV resistant 2-pot system on top of that.

Thousends of wooden boats have been restored wordwide using this system. Especially on a laminated ply (cold-molded) dinghy ( like your flying dutchman ) it could work very well if you take care of a proper preparation and have a well dried hull.
I remember the latest build "Heine" FD's ( 80-ies) were even build in laminated ply/epoxy
a 2pot PU really works very well on epoxy-coated wood. I agree it does not work wel on bare wood.

Watermaat, you've apparently missed the point of my first post or don't understand the idea of epoxy encapsulation to stabilize wood.

In a nut shell, epoxy is an effective wood sealer, but only if if can completely surround (encapsulate) the part in question. If there is sufficient epoxy film thickness, the current moisture content of the piece is locked down and the wood becomes dimensionally stable (for the first time). As this dimensionally stable part, is glued and fastened to it's neighbors in a similar way, they you're correct, a 2 part urethane is a good choice.

Unfortunately, in this case each separate piece, fastener hole, notch and cut out can not be coated with sufficiently thick amounts of epoxy, to insure complete encapsulation. Given this fact, the separate elements of the structure, will not be moisture stable and they will naturally move to environmental changes. This movement will crack and tear both epoxy and urethane coatings.

This isn't supposition, but well tested fact and the reason I recommend the "softer" approach of varnish or single part urethane on this boat. As a rule epoxy coatings on repairs and restorations is misunderstood, often over used. The reason is as I stated, the part has to be embalmed, entoombed, completely coated, including fastener holes, dings, nicks, etc. other wise moisture will find a way into the wood, have limited exit points and movement continues, not to mention the promotion of rot.

Ok,folks i guess i'd better explain things a little better,as i think it would help.The FD has fibreglass hull with ply decking and cockpit floor.The original ply was not marine grade and has ALL delaminated.My idea was to remove all ply and replace it.Encapsulating it.The deck will be painted,but the floor will be left varnish.

Anything you can get at all sides of can be sealed with three coats epoxy wet on wet. So the decks are a good candidate.

See my FAQ if you haven't already ... FAQ - Boat Building and Repair Methods - Plywood Epoxy Fibreglass Cedar Strip - Michael Storer Wooden Boat Plans

If you have any areas where the timber looks a bit dodgy in the main part of the hull it can be worth consolidating problems areas with epoxy - or if there are cracks use epoxy and very light glass (2oz - 75gsm) to go over those local areas. The light glass just about disappears completely so you can still keep the interior clear finished.

Put any pics up of localised problem areas and PAR and I can help.

MIK

Originally Posted by PAR

Watermaat, you've apparently missed the point of my first post or don't understand the idea of epoxy encapsulation to stabilize wood.

In a nut shell, epoxy is an effective wood sealer, but only if if can completely surround (encapsulate) the part in question. If there is sufficient epoxy film thickness, the current moisture content of the piece is locked down and the wood becomes dimensionally stable (for the first time). As this dimensionally stable part, is glued and fastened to it's neighbors in a similar way, they you're correct, a 2 part urethane is a good choice.

Unfortunately, in this case each separate piece, fastener hole, notch and cut out can not be coated with sufficiently thick amounts of epoxy, to insure complete encapsulation. Given this fact, the separate elements of the structure, will not be moisture stable and they will naturally move to environmental changes. This movement will crack and tear both epoxy and urethane coatings.

This isn't supposition, but well tested fact and the reason I recommend the "softer" approach of varnish or single part urethane on this boat. As a rule epoxy coatings on repairs and restorations is misunderstood, often over used. The reason is as I stated, the part has to be embalmed, entoombed, completely coated, including fastener holes, dings, nicks, etc. other wise moisture will find a way into the wood, have limited exit points and movement continues, not to mention the promotion of rot.

I was aware of this and totally agree with your statements. The only point I am trying to make is: if you want less regular maintenance you should go for a well done epoxy system, otherwise you will still have to varnish on a more regular base. I hope you agree on this?

Originally Posted by HELLICONIA54

Ok,folks i guess i'd better explain things a little better,as i think it would help.The FD has fibreglass hull with ply decking and cockpit floor.The original ply was not marine grade and has ALL delaminated.My idea was to remove all ply and replace it.Encapsulating it.The deck will be painted,but the floor will be left varnish.

I think your approach is right.
If you are replacing the ply I personally would go for a varnished deck too, that makes it an absolute beauty.
Sailing a F.D. is GREAT, so every effort to get it back on the water will make this worthwhile.

I think we all are in general agreement. Since this project will be working with new sheets of plywood, rather then fixing what was there, encapsulation is possible, so Helliconia54 has the option of using all the usual suspects for a finish. If given the opportunity (like here), I'd use two part urethane over epoxy for the durability and longevity it can provide. Also I'll second sailing one of these as great fun.

Hi Ralph, MIK and PAR are on the money.

However, I am in awe of the size of this job and our friend HELLICONIA54 is to be congratulated for considering it! The FD is sailing history now and there are very few examples of this Olympic thoroughbred around these days and the good ones are mostly in museums.

I had the privilege of sailing a cold-molded wooden FD, just the once in what was something like only 5 knots and on a fresh water lake in South Africa. The memory of that sail has been brought back, and I can remember the awesome power of the thing going upwind. It was quite light wind but I was a teenager and with my girl crew we could not have weighed more than 220kg between us, and she was out on the trapeze. Just an awesome boat.

This will be a rewarding project for you!

We did have this restoration in one of the other sections. Not a lot of detail I am afraid.

https://www.woodworkforums.com/f32/fl...oration-41658/

MIK