Dry Strip Planking

10mm 1.2 x 2.4 sheet £67 in UK.

Seems there are some specialst sellers, much as there used to be for "Siberian Larch"

 

Yes

67 in UK x 1.2 = 80 Euros

12 mm, 2.4 x 1.2

66 Euro + Tax = 80 Euros

►TABLERO ALISTONADO PAULOWNIA 12mm | iPaulownia https://www.ipaulownia.com/es/producto/tablero-alistonado-paulownia-12mm/

 

I built a canoe with wb glue and encapsulated all in epoxy.

No problem. I probably would not with a larger boat.

 

The calculation for my 1 Ton Surfboard (ISO Category A Hull) is 9.75 mm (14 Newtons / mm^2 = 0.5 x 28)

So with 12 mm + 800 g sqm of fiber + Epoxy...

Let's see, I don't want to get too excited but now that the doctors have released me and with a little luck if I recover on the money issue... I see a light at the end of the tunnel and let's hope it's not a locomotive, haha

It's totally funny: surfboards are made of paulownia (!)

Well, I don't bother you anymore in this thread,

a Big cordial greeting to all

 

Hi everyone, thanks for all your input. Much appreciated.

First off, Carlosk2, honestly am not sure what to make of your posts!!!!

RWatson - rather than going for a wide gap, im' thinking of a thin gap as in a post by Catmando2: "My favourite way at the moment is to dry stack the planks using a thick paint scraper as a spacer... Closer to the 1mm gap"

Ooh and I got an answer from the boat by the river guys about the raptor nails - they left them in....

Speed Strip tongue-and-groove strip planking https://www.boatdesign.net/threads/speed-strip-tongue-and-groove-strip-planking.624/page-2#post-116927

Rumars - test panels great idea! Thanks.

Russel Brown - lovely looking projects - thanks for sharing the photos!

DC and Fallguy - yes to wanting to avoid epoxy mess. I am certainly considering using polurethane glue to bond the strips together, however, I'm aware that the glue expands to fill in gaps, but this foaming has no strength, so it's got to be a better fit than if you were glueing with epoxy which of course adds time. Certainly the other benefits for me are cold weather application.

Fallguy - yep, am aware of the problem of dry seams - possibly prime with a thin water based epoxy first to avoid this?

Fallguy - yes was thinking of going for a thicker epoxy putty as lighter is good and from what I've read full strength is not necessary. Plus less sticky mess to end up on the floor! If using the female mold happy to only partially fill the gaps from the inside so when the hull is flipped the wood can be faired before the final filling of the gaps from the exterior.

Peterbike - it is a risk building with wood. I don't see that building with Paulownia is necessarily any riskier than building with balsa. Certainly I'm aware that a foam boat would probably have a higher resell value as being seen as less of a potential problem to a new buyer. I certainly wouldn't consider using PET foam as the shear strength values are too low for me....

 

The bulkheads can be installed on a male mold too. They are one of the building stations. Also, stringers and other structural members are installed. At least that is the way I have built many boats.

 

That is really heavy. Surfboards are usually less than 20 lbs (9 kg)

 

6:10
Does such milling have any significance in terms of strength?

 

This is glued wood. I would prefer integral wooden strips.

 

A very large boat built on male stations must be turned 90 degrees for bulkhead installation.

You asked, I answered, there is no debate my friend. I went down this road in 2016 on this forum and learned what I now share.

 

The point was it is machined to a thickness, you can just run it through a table saw to the size of the strip width you require. It looked more expensive to buy "machined on all 4 sides" lumber, which would require even more cutting.

 

"honestly am not sure what to make of your posts!!!!"

(?)

Well very simple

1) I have given you an important piece of information from a good scientific study: 28 Newtons / mm^2

2) I have defended this material

3) I have pointed out the importance that after many years of experience the founders of West System (who know something about Epoxy resin) gave to a good layer and

4) I have given you the address of a very good European plantation

 

The bulkheads are stations too. The stringers, chine logs, and other structural members are all marked and cut from the loft. I have built many boats like that. It is much easier than hovering over a female mold to install bulkheads and stringers.

 

Thanks Carlos!

Yes, I agree that on paper Paulownia looks very promising. I have already been in touch with ipaulownia asking for a price for rough cut planks, but currently have an interesting lead here in France with some older growth wood than the 9 year growth wood from Spain..

Gonzo - Of course both male and female molds have advantages and disadvantages. Ian Farrier used the male mold initially for the F27 prototype, but didn't get on with it for a foam build and so switched to a female mold. For him "Advantages over the old male mold method of foam core construction are all the screws are on the outside and stiffening bulkheads are added before the hull is removed from the mold. Anyone who has had to climb inside a male mold to remove the screws will appreciate the external screws, and once the hull is removed, one is not presented with a huge flexible hard to handle ″whale″."

As a newbie, I have no dog in the fight, and will use the female mold as that's what is in the plans....

 

When strip planking was common in Aus (I was supplying epoxy to 30 builders of cats over 30' long within 30 kms of my shop and was only the third largest supplier), at least one builder planked dry, then glassed. Cut outs showed the resin had wicked all the way through the join. PU foaming glue had only just appeared and was a better option than applying epoxy to the planks.
We built a boat (Riverside Oaks, 8m Grainger tri, 1987) in female moulds. It is truly painful. Set up fairing requires pushing the batten onto the frames rather than draping them over. Stepping over the frames was tedoius and easy to miss and possibly knock things out of fair. Working on your knees for the shaped planks along the bottom was painful and slow. Ian used female moulds because they suited his sheet foam technique foam. Not many strip boats were built after he realised the benefits of foam, possibly not worth his time changing the plans? I strongly recommend a male set up for strip. If you are unsure, build the floats first, using female, then decide for the main hull.

AFAIK, I built the first Paulonia (kiri) strip planked boat in Aus. Had to wait for the trees to be harvested. 35' proa, 8mm planks, 200 gsm uni either side. Washed up on the beach by big waves in a storm, no damage. It is nicer to work than cedar, lighter, not as toxic, rot resistant and does not soak up water like balsa does. Does not look as good clear finished.

Riverside Oaks had 6mm glass uni across the planks. 400 double bias around the dagger case. It is still going strong, despite a pretty hard life. The first large strip plank boats were built in NZ. 30' tris with similar laminate over 10mm planks. Also still going strong, afaik.

Truly rough cut is hard to work with, needs to be cleaned up. Resawn (big bandsaw) is fine.

Use bulkheads where possible instead of frames and/or leave frames in when turning. You only need a couple to keep everything rigid.

In humid conditions glass the other side as soon as you can, or it may move.