Dry Strip Planking

[montero]

Water based glues for boats are a good idea? I see 3 types of glues here epoxy, pu, Titebond 3.Expanding pu sounds promising is it durable enough?

 

[skaraborgcraft]

2. Raptor nails. They have no shear strength so there must be enough epoxy between strips. The epoxy mix must be strong enough for that.

Not an issue if being glassed on both sides.

I recall Mark Bowdidge having a "gapped strip plank" on many of his designs, sheathed inside and out.

 

[peterbike]

Wrekin, paulownia is fairly new - so no long track record.
Gary Baigent an ex forum member built one of his trimarans out of it.
The boat failed big time after not a lot of time. On investigation he found he had "black mush between 2 skins of epoxy fibreglass"
You could troll back thru the forum, to find the entry yourself. (2/3 yrs ago ?)
To me paulownia falls into the same category as, balsa & radiata pine. Both last about 5 minutes on exposure to water.
How many people are cutting the balsa out of their hulls & replacing it with foam atm ?
Balsa boats are mostly not wanted, unless a good price.
If you want to work with timber - I would say go for a full timber interior
Selling a palown boat in future after you have sunk in a lot of time & money, could be heart wrenching.
If you want to be environmental - go PET foam.
Sorry to rain on your parade, but it had to be said.
ciao

 

[CarlosK2]

SurfBoard

Fish 6'4 ORIGINAL SERIES - Prism Surfboards https://www.prism-surfboards.com/en/fish/fish-64-paulownia-original-series/

 

[CarlosK2]

Suppose that Paulownia were a wood as wood as bad as Okumé.

In both cases I would put about 800-900 grams sqm of fiber in order to be able to pile up 1 kilo of Epoxy per square meter ensuring impermeability against the pressure of sea water, and on the deck 250-290 grams

Out of mahogany...

 

[CarlosK2]

Or Birch

I am very fond of birch, but the same thing: I would not leave it without waterproofing

 

[CarlosK2]

I want to say that I am very cautious and I do not take into account the wonders that people say about this wood.

 

[CarlosK2]

Copy and paste

"Salwater resistant
Probably the most interesting characteristic for making wood surfboards: if it resists salt water it means there is no need of fiberglass or any other chemical sealer!"

Why wood? - Flama Surf https://flamasurf.com/content/8-paulownia-wood

 

[skaraborgcraft]

On investigation he found he had "black mush between 2 skins of epoxy fibreglass"

To me paulownia falls into the same category as, balsa & radiata pine. Both last about 5 minutes on exposure to water.

Lots of balsa cored boats decades old still without issue, not all build quality is equal. How did the water get in?

 

[CarlosK2]

Apparently there are paulownia surfboards only with very light protection such as some type of oil

But I think/plan to follow some conservative numbers for the thickness of Epoxy

Farewell to one of boating’s giants https://maineboats.com/print/issue/farewell-one-boating%E2%80%99s-giants

Gougeon Brothers In Memoriam

 

[CarlosK2]

The Art of Resin Coating

The Art of Resin Coating https://woodensurfboard.com.au/blogs/bywater-surf-blog/the-art-of-resin-coating

"While paulownia timber absorbs less salt water than many other types of wood, the resin coating will make the board completely water-resistant."

 

[skaraborgcraft]

They home-build a lot in strip pine in Eastern Europe. I think even PET foam with the same density and crush resistance will be significantly more costly than the wood.

 

[fallguy]

I’ve had zero delam on my canoe related to glue. Actually, in 20 years, only one spot of delam from setting it down hard one day, and it was about the size of a dime. I never noticed it until water got in and turned it black.

Where did you read that epoxy won’t stick to cured and sanded yellow glue?

 

[CarlosK2]

I don't know where the trick is, I mean I don't want to get too excited; but the truth is that I am very excited because with this wood we get some very nice numbers for a light sailboat.

 

[CarlosK2]

28 Newtons / mm^2
0.30 Density

(?)