Scarfing Ply

[mojounwin]

G'day Everyone,
I'm building a 8m strip plank trailer sailer. The decks are fibreglassed plywood. I'm just wondering what would be the best way to scarf the ply wood?

Any ideas?

Cheers
Mike

Also check out my website
http://www.geocities.com/mojounwin/colson.html

[markharrison]

There was a great scarfing jig in a Wooden Boat magazine a while ago that could scarf a whole sheet in one pass using a circular saw. It's the best I've seen yet.

Unfortunately, I don't have the magazine (borrowed it from the library) but a quick search on their site (http://www.woodenboat.com) suggests to me that this the issue you are after is number 175. Try your local library.

[bitingmidge]

Mike.

Mark is correct, I've just looked it up, it's pretty scary to my way of thinking, but I'm happy to scan a copy for you. Send me a pm with your email address if you like. Just don't tell anyone so we don't get caught up in copyright issues!

The boat looks terrific by the way: I'm guessing you are going to paint the deck and cabin liner? In that case by the time you've built the jig you could have cut the scarfs (scarves?) with a planer, or even hand plane.

Mark the length of the scarf on both sheets, clamp one on top of the other on the line of the scarf, then plane from the outside bottom of one sheet to the scarf line of the other- :confused: :confused: I can't understand that so I don't know how you will!

Basically if you plane both together the angle will match, any minor undulations will be taken up with bog when you glue.

cheers,

P (Nice to see someone else using Woodenboat as a resource Mark!)

[Paul B]

I stacked the sheets when I built my boat (ok so it was a kayak). Put a piece of scrap ply underneath and another on top so that there are four layers, then just use a hand plane and clean up with a flat sanding block. The two sheets in the middle will turn out nice while the scrap pieces will be less than perfect. Hope this makes sense.

[Daddles]

I've scarphed quite a few sheets while at TAFE and it's not hard with a hand plane ... though having a sharp no7 is verrrrry nice. You can even stack a few on top of each other and do the lot in one hit. If you've got an electric plane, you can use that to get it close and then the hand plane to finish off.

The joints don't have be perfect - remember, epoxy likes a gap rather than a voidless joint.

Unless you have a lot of sheets to do, don't bother with a jig.

Richard

[sinjin1111]

Ok, well the way i used to do it was place the sheets you needed one on top of the other.
I used a router as super sharp hand plane. The problem i see with a Circular saw is things like the sideways float in the blade. For a really nice scarf you want the edges wafer thin.
Anyway a really simple jig is the use a router to knock off 99.99% of the stock then use your super sharp hand plane for a final pass.
The way i used a router was two pieces of 6 x 1 timber or ply doesn't matter so long as its dead straight as guides one on top of the sheets and one in front of the sheets. If you draw it to scale side elevation you can see where the pieces of timber need to be placed to get the right angle (scarf angle). Mount your router on the piece of ply rounghly the width of the router and about 400mm long make it about 25thick if you have any you don't want it to flex in any way.
The idea is the the router mounted on the ply slided up and down the edges of the timber as guides. Its very simple, really accurate and quick.

[bloggs1968]

Mike,

Just use a hand plane to cut an 8 to 1 bevel in the ply. If you keep the glue lines parallel when planing it is an easy task. Ensure the edge of the ply you are scarfing is well supported by the edge of a bench or on the edge of some saw horses as the feather edge will be delicate.

be aware though that due to deck camber, the scarf edge will not be straight but rather a clightly curved line. Ususally not enough to worry about but if camber is really strong it may be. easy fix, just plane a curved scarf.

regards,

AD.

[mojounwin]

Cheers Guys for the suggestions.

As people have said I might just try it by hand as there isn't too much scarfing to do.

Mike

[The Live Wire]

If you want the best advise contact: [email protected]
He has decades of timber catamaran construction experience and has designed a number of boats himself. He was designer of the Blade F16, which is currently receiving great reviews in the US and Europe. It has shown enormous promise in it's racing results.

He has a web site dedicated to ammateur boat building, but I can't quite find it right now. Good luck.

Cheers The Live Wire.

[Salty]

Again relying on the fantastic resources of Woodenboat on page 128 of the December 2005 Issue is an advert from John Henry Inc. I have seen the ad appearing for the last 5 years at least so they must sell some units from the ad and it always looked like a good solution to scarfing a whole sheet. Email address for JH is [email protected]
Snail address P.O.Box 7473-WB Spanish Fort, AL 36577 Ph 251-626-2288
I have relyed on the Lie Neilsen low angle jack plane and a keen blade and eye for the small amount of scarfing needed to build my 18' Oughtred John Dory.

[Drifter]

have a look at the One Ocean Kayaks site, I think they have details of making a scarfing jig , although I agree with others that it is quite easy to do with a sharp plane.
Robert

[Tony Hunt]

This jig (or some variation on it) is also really worth considering for anyone scarfing big sheets of ply.

http://www.boat-links.com/Scarfing.html

[catbuilder]

That my friend is a nice looking bit of gear, thats something I could see myself building one day. Its looks a fairly modern design, how old would it be? Are their others that you know of? I hope it serves you well, looks great.

Matt