white oak and epoxy ?

[byankee]

There is considerble controversy around the use of epoxy to glue white oak. Some say it's fine. Others say it's not. I have polled several epoxy manufacturers (West Systems, System Three, Raka, MAS, Progressive Epoxy Polymers and US Composites) and spoken to manfacuture's reps for System Three and MAS at the WoodenBoat show and none of them think there is any problem or issue. Yet, the argument persists among amateur boat builders.

What say you? Is epoxy suitable for gluing white oak laminations intended for structual applications (i.e. frames) in wooden boats?

Also: For only the folks out there that have had direct personal knowledge of or experience with white oak laminates glued with epoxy in real wooden boats, how many failures of the laminate do you know of? I'm not talking about test samples (although that information is certianly useful). I'm talking about actual applications in actual boats?

[PAR]

I have tested, restored and repaired with epoxy and it can work with two precautions. The laminates need to be thin and the oak well wiped with solvent of choice, just before epoxy application. I don't recommend laminates over 5/16", having found 3/8" pushing it. I use acetone, but alcohol, plus a few others can work, but may be product specific, so check with the brand manufacture.

[skpr44]

I had occasion to replace the fore and side decks on a 1968 42 Trojan Sea Voyager in 2004/2005. It was neccesary to replace all the frames which were made of 3/4 x 1 1/4 strips of white oak which were built up 4 high in order to create 3" frames. I used West System with 404 additive. The frames were topped with 1/2" marine plywood which was epoxyied and screwed to the frames and then covered with mahogany deck planks.

This boat is in the water 12 months a year as a liveaboard in Ontario and used regularly for cruising.

To date the deck is very solid with no signs or sounds to indicate any failures.

[skpr44]

With respect to Greg's question the deck frame laminations were done in march of 2005. the work was done in Ontario, therefore the temperatures were in the 0 to5 celcius range.
I did leave the frames clamped for approximately 10 days and applied heat with an infrared heat lamp.
Since that time the boat was launched into the Otanabee river from a trailer near Peterborough and travelled down the Trent system to Lake Ontario where it stays in the water year round.

[PAR]

Skpr44, you laminated frames haven't really stood much of a test of time yet. Load cycles in a wet condition will eventually determine if your laminate schedule has held up. Because your "strips" were 3/4", I suspect they'll hold up well, if the tannins were removed before the epoxy went on and a good tooth was on the oak.

[skpr44]

Only time will tell the ultimate result. As I live on the boat any changes will not be missed.
Perhaps an annual report is in order.

[wdnboatbuilder]

I have found that the grain is too tight to allow the epoxy to be drawn in the oak, so the bond is not all that great. Par is correct by wiping with some solvent it will open the grain but it will not allow the epoxy soak in the oak. WHAZZZZZ up PAR.
Bruce

[PAR]

Hey Bruce, same old S... (different fly's), the big rush to get things ready for the spring shows.

If you warm the oak to about 100 -120 degrees it will suck in the epoxy. This is how I laminate frames, hot sticks, hot goo, brought together in a cool place (prevents out gassing)

[wdnboatbuilder]

Interesting, Does that also work with Elm?

[PAR]

Works with any wood and many are religious about it. The wood expands slightly when warmed, so does the air and liquid in the cellular structure. Move the piece to a cooler location and add warmed epoxy, which has a much lower viscosity then usual and soaks well into the wood fibers. Since the wood (and epoxy) are cooling, as are the liquids and air in the cellular structure (of the wood) they are contracting, which tends to suck the goo further into the wood (filling the voids left by the contracting materials).

Of course some woods are particularly dense, have interlocking grains, etc. which limits penetration, but the warm on warm trick will get you the best you can get, especially if vacuum bagged.