scarf joints

Submitted by Michael Moberly on Tue, 04/28/2020 - 10:00

Ok, I have a question. How many scarf joints are to many? I cut up a piece of Red Cedar 2x4x15 and out of that whole board I got maybe five  3/4 X3/16 strips. The board had a couple of nots that fractured during the milling process. I can forget about any type of grain pattern and spend a day or two Scarfing joints or should I just scrap that piece and start over.  Did I mention I am building the 18 ft guillemot L

JohnAbercrombie

Tue, 04/28/2020 - 12:00

Except for the strips at the sheer, which I like to be full-length (so usually scarfed) , I use shorter strips and butt-join them.

But on a clear finished, 'work of art' kayak, that probably wouldn't be acceptable.

It's a good idea to break strips at knots and weak points, like you did. 

Whether to 'make do with what you have' or get a new board and consign the lesser quality strips to the stir stick and kindling box is really a personal decision, I think.

Michael Moberly

Tue, 04/28/2020 - 14:27

In reply to by JohnAbercrombie

John,

Thanks for the fast reply and the input. I am not going for a work of art on my first attempt. I am leaning toward more  of just a working Kayak. I’ll bust out my artist on the next one. my budget tells me that short strips are the way to go.Thanks  

Allan Newhouse

Tue, 04/28/2020 - 17:35

Prefer short strips. I built a 16 foot kayak from 6 foot strips.

That was about ten years ago and I have never had anyone ask why it has so many joins in the strips.

I very rarely use strips over 12 feet.

I use the belt sander scarfing method described in Nick's book and I join them in place. Joining them before fitting negates some of the big advantages of short strips.

Michael,

To clarify, when you write that you got only 5 strips, do you mean 5 full length strips and that the rest of the wood, due to knots, yielded only shorts?  In other words, if you are willing to use scarfs, you yielded more usable material, correct?  I ask because I am about to buy wood and am struggling to figure out how much to buy.

Thanks, Steve

Nick Schade has a table to determine the amount of strips needed for selected kayak builds. As far as Cedar quality, you can buy mill run boards, that are only really expensive, and reject 75% of it. Or, you can buy "small, tight knots" boards for a kings ransom and reject 10% of it. Or, you can buy "clear" boards, that you might be able to trade your oldest son for, and use 100% of it. (A kayak built using small, tight knots is really quite unique looking)

I went through the "search the big box stores" for useable wood. Spent way longer looking for wood than building the boat :(

I live in a very small town, no stop lights or signs, straight through at 40 mph. We have a very small lumber yard that I can order Cedar anytime. If I can order it here anyone should be able to get Cedar ordered locally. There are saw mills that will sell direct, good quality and cheaper price, the shipping cost will raise your hair !!

One last thought. I know of no one that builds "just one" kayak so don't try to buy just enough material. Buy more than you think you will need. You will build another boat and - - - - material will be more expensive then :( :(

Allan Newhouse

Thu, 04/30/2020 - 17:39

There are other sources of WRC that might be available to you.

I built my first stripper, a Night Heron, from a timber yard scrap heap. They were the thin reject strips cut from the sides of the huge boards which they ripped into smaller boards.

I built my Night Heron Double from second hand skirting boards and  have used WRC lining boards retrieved from various bathroom walls or kitchens on several other kayaks.

So first, I am in Los Angeles and am jealous that you are in a small town.  Second, I have spent more time watching Nick's videos and pestering him with emails than I care to admit. And yes, the cedar is expensive here.  I'm building a Petrel Play and the 25 board feet that Nick suggests will be about $400 bucks from the two lumber yards I've found so far.

My wife and I spend a lot of time at the islands off the So Cal coast, so yes, there will be a second kayak coming soon.

Thanks and stay safe.

JohnAbercrombie

Fri, 05/01/2020 - 02:02

You could investigate the possibilities for Pawlonia or Basswood as alternatives to WRC. 

$16 USD/bdft for WRC seems overpriced to me, but I guess you are a fair way from the nearest WRC forest.

JayBabina

Fri, 05/01/2020 - 08:15

SSpencer - you might want to try looking for Redwood. W Coast is Redwood. You might find some used or cheap? One time along my building paths I ran into a guy taking down a redwood deck. He gave me a bunch of long boards. Can you imaging a redwood deck these days. And I'm in CT. Never be afraid to advertise for used wood. You'd be surprised whats around in peoples garages and back yards.

JohnAbercrombie

Fri, 05/01/2020 - 12:20

I notice that Bonhoff Lumber has WRC, Basswood and also Spanish cedar listed. I built my Njord using 4mm Spanish cedar strips and it came out well. so if the price is right that might be another possibility.

 

But, really - you didn't think that building a strip kayak would be a cheap way to get a boat, did you?

:)

One way to rationalize the materials cost is to price your labour. If you think of it that way, it's a $5000+ kayak and the wood is only a few hundred dollars of that.

 

SSpencer

Fri, 05/01/2020 - 13:06

In reply to by JohnAbercrombie

John, I am a sailor and have spent ten years rebuilding a 41 footer.  I know better than to use "boat" and "cheap" in the same sentence.  I don't mind spending the money on the WRC.  The value of the distraction these days offsets the cost of therapy I might need otherwise.  BUT, I am very interested in alternative wood varieties and will keep exploring.  Setting up the forms this weekend...

daviddewitt

Sat, 05/02/2020 - 07:37

Has anyone every tried an alternative to wood such as diviniycell or any of the other foam core materials that are used in the boat building business (e.g. https://www.jamestowndistributors.com/userportal/show_product.do?pid=15…)?   Obviously the boat would need to be painted and would almost certainly need a second layer of glass to have a reasonable amount of impact resistance.   

daviddewitt

Sat, 05/02/2020 - 07:45

To clarify my previous comment.   My idea was to rip the foam (which is sold in 1/4” thick sheets) into 3/4”  wide strips and then plank the boat in the normal fashion.   While fairing the hull one would almost certainly have to sand very, very carefully

JohnAbercrombie

Sat, 05/02/2020 - 18:26

Point65 was one manufacturer that used 'Coremat' in their glass boats. It's like thick blotter material with perforations. Any damage to the outer glass layer and the core was in trouble. I wonder if the same problem would exist with foam?

If the foam is compressible at all, I think sliding the boat over a rock would dent the foam and break the adhesion to the glass layers.

I've thought of using foam core but I think it would be tricky to work with. Gluing the edges of the planks? Fastening to the forms?

Wood is actually a really good material - even at 1/8" thickness, I think it would beat foam core.

One application for foam core might be to replace plywood in a stitch and glue boat (or a strip design adapted to S&G - like the Black Pearl?)

I am using yellow cedar.

2 pieces 2x8 rough sawn tight knot 18' long (I had to have them cut to 4 x 9' long to fit in my truck) total cost Can$109.00,

My yeild was only enough to build the 1 kayak after trimming, planing, discards due to erratic grain etc. (and it was a lot of work to do the milling) but it was cheap.

There are good alternatives to WRC.

Yellow cedar has higher density and is heavier than WRC, but is almost as strong as fir and weighs less than that option. Also yellow cedar has higher modulus of elasticity (less brittle than WRC), mills beautifully, and bends quite well.

I used scarf jointed pieces for the hull (painting the hull), but I have enough clear straight grain quarter and/or rift sawn strips to to do the deck.

Well, after a lot of exploring, I was able to find wood at a small yard in the central coast (about 3 hours north of Los Angeles).  Fortunately, I had a meeting up there and it all worked out - prices were 1/2 of what I found in LA.  $8.20 for WRC and $6.20 for Alaksan Yellow.   I found 14 footers and also had to have them cut to fit on my roof rack without bouncing around for the 3 hour drive back.  The boards are all 2x6 and rough.  Interested to see what the yield is when I get to that point next.