Malahini Lumber Joining

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theGreek
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Malahini Lumber Joining

Post by theGreek » Fri Sep 06, 2013 3:25 am

Hi there,

I am new to this forum and in the boat building community. I have recently purchased the Malahini designs and two books on how-to.
I have been researching on the lumber that I will need in order to build this boat. I 've ended up in White Oak. May I mention that I live in Athens, Greece.
My problem is that the White Oak does not come in more that 10 feet long boards (nor mahogany). Do I make joins? Should I use a different type of wood? I have asked many lumber suppliers and they told me that the maximum length is approx 13 feet.
I haven't started building the boat yet, but I would like to start in the right direction.
At the moment I have the space the tools and the excitement to build.
I am looking forward to read your suggestions.

Thank you very much

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rbrandenstein
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Re: Malahini Lumber Joining

Post by rbrandenstein » Fri Sep 06, 2013 7:11 am

I also used white oak and 10 feet is common. My hardwood shop stocked 9 and 10 footers, but I had to special order a 13' piece for the keel.

Since the chines and sheer are almost 20' you need to join the two pieces with a scarf joint. I made a jig for my circular saw to cut the angle and then epoxied them together.
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Bob
Completed Malahini (launched 6/24/2012)
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theGreek
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Re: Malahini Lumber Joining

Post by theGreek » Fri Sep 06, 2013 9:11 am

Thank you very much for the information! I now feel more confident about my project.

By the way you did an AMAZING job on your boat. Congratulations! I hope I get as close to your result as possible!

I do though have another question. At what point did you choose to join the woods? I am trying to understand where it would be better to make the join i.e. towards the aft or sheer? Did you also use plywood lamination for extra reinforcement?

Sorry for all the questions. You know how newbies are these days.....

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rbrandenstein
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Re: Malahini Lumber Joining

Post by rbrandenstein » Sat Sep 07, 2013 8:33 pm

There is much less curve to the chine and sheer from the mid point to the stern. So, you should make the joint as far back as you can. I joined two 10' pieces and used the full 10' from the stem and trimmed it at the stern.

The purpose of the scarf joint is to provide enough surface area to not require reinforcement. Adding plywood is not necessary. If you added extra wood it would not curve into a smooth curve, possibly creating a flat spot.
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Bob
Completed Malahini (launched 6/24/2012)
http://bobsboatbuild.blogspot.com/

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ttownshaw
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Re: Malahini Lumber Joining

Post by ttownshaw » Mon Sep 09, 2013 7:27 am

Also, for your chines you might consider doing them in laminations (just like the sheer)...best of luck and share lots of pictures. We will be here when you have questions.
Bill

I told my wife we needed a three-car garage for my projects...she told me to ask her for permission next time before I buy a house.
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theGreek
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Re: Malahini Lumber Joining

Post by theGreek » Fri Sep 20, 2013 6:42 am

Sorry for the late reply. I ve been away. Thank you for all the info. Really helpful.

Could you also tell me the type of join you make on the side and bottom planking? The plywood comes in 250cm (8.2 feet) length so I will have to join them. I read in the boatbuilders notebook that I can make a butt join with inner lamination join. What I was thinking was

a) The lamination will make the plywood stiff so it will not bend smoothly around the frames
b) The lamination will overlap on the chine and sheer. Am I supposed to trim it there? (sounds a bit stupid, but I thought to ask)
c) Since the side planking is 18 feet long, I will have to join 3 pieces together. Isn't that a bit too much? Is it ok?

Again thank you for all the information.


Regards

Konstantinos

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ttownshaw
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Re: Malahini Lumber Joining

Post by ttownshaw » Fri Sep 20, 2013 9:10 am

You really have two options for the side and bottom planking. You can either scarf the plywood together (which is what I did) or you can butt join them in place (which most people do). If done properly the butt joint is just as strong, will maintain the proper curve, and is (in my opinion) easier than the scarf joint. Which ever method you choose will work. Just look at some other builder's photos for reference. Here are a couple links to some high resolution pics of mine...you can see I scarf joined in about 2' of plywood in the center section. If you look closely you can see the angle of the scarf joint on the plywood.

http://unitybuild.net/data/storage/atta ... 806f0a.jpg
http://unitybuild.net/data/storage/atta ... b30309.jpg

Hope this helps some.
Bill

I told my wife we needed a three-car garage for my projects...she told me to ask her for permission next time before I buy a house.
http://www.unitybuild.net

theGreek
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Re: Malahini Lumber Joining

Post by theGreek » Sat Sep 21, 2013 1:28 pm

Thanks Bill for the photos. Very useful. Problem is, that the side plywood is 3/8 thick, so a scarf join will be very difficult. Is yours that thin?

Konstantinos

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ttownshaw
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Re: Malahini Lumber Joining

Post by ttownshaw » Sat Sep 21, 2013 2:09 pm

Side planking should be 1/4" and the bottom can be 1/4 or 3/8". In my opinion the curve at the transom would be impossible to do with 3/8".
Bill

I told my wife we needed a three-car garage for my projects...she told me to ask her for permission next time before I buy a house.
http://www.unitybuild.net

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galamb
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Re: Malahini Lumber Joining

Post by galamb » Sat Sep 21, 2013 2:25 pm

West System has a scarfing jig that fits on a circular saw and cuts the perfect scarf angle on plywood up to 3/8" thick, and with a bit of finishing with a plane, up to 1/2" thick.

I used it on the side panels of my build and used a mix of scarf joints and butt joints on the bottom (forward section 2 layers of 1/4" - scarfed, and back when it flattens out, butt joints on the 1/2" panels).

The butt joints work fine in a flatter section since you block between the panels. But anywhere that the joined panels have to bend/curve (as you get closer to the bow), the scarf joints just flow so much nicer.

The scarfing jig is not cheap, currently listing at 75 bucks, but it's pretty much a "attach it and scarf" with next to no messing around.

I figured it's worth it because no matter what you think, you ARE going to build another boat at some point (maybe 2 or 3 more) :)
Graham

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

theGreek
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Re: Malahini Lumber Joining

Post by theGreek » Sun Sep 22, 2013 4:22 am

Sorry for the error in the thickness. Yes what I meant to say was 1/4 " (I am still adjusting to the imperial system).

Thank you for the jig info. I will look it up.

Regards

Konstantinos

Jim Hohn
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Re: Malahini Lumber Joining

Post by Jim Hohn » Sun Sep 22, 2013 9:25 am

Graham, I checked West System for scarfing jig and saw nothing. How long ago did you acquire this jig ? I would really like to get this tool.
Jim

hdunk
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Re: Malahini Lumber Joining

Post by hdunk » Sun Sep 22, 2013 9:54 am

Here is a link to build one with good documentation for scarfing jig.

http://forum.woodenboat.com/showthread. ... -Jig-Ideas

http://forum.woodenboat.com/showthread. ... -Jig-Ideas

Be sure to use the entire link. This is the one I am going to use.
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galamb
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Re: Malahini Lumber Joining

Post by galamb » Sun Sep 22, 2013 11:48 am

It's West System product number 875.

Here's a link showing it in use http://www.duckworksmagazine.com/05/rev ... /index.cfm

And here's the link at West - http://www.westsystem.com/ss/special-tools
Graham

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

Jim Hohn
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Joined: Tue Aug 27, 2013 1:46 pm

Re: Malahini Lumber Joining

Post by Jim Hohn » Wed Oct 09, 2013 12:17 pm

galamb & hdunk, Thank you !!!

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