Scarfing, oh the joys of joining two long pieces of wood into an even longer piece of wood. There are many methods to scarfing plywood; The traditional, hand plane method, the Belt Sander method, the circular-saw-on-a-jig method, and the Router Jig method. We’ve tried them all. With the wood layers as a guide, all work, though some more labor intensive than others. We’ve just recently acquired a new Shaper Origin, which is a Hand Held CNC router and when it comes to our next scarf, we’ll try that method. The goal of a good scarf is a nice, even slope that will match the other piece of wood you intend to join. The more gradual the slope, the more contact area for a theoretically stronger joint. It’s recommended to have your scarf taper at at least an 8 to 1 ratio of wood thickness and sometimes even a 12 to 1. We use the 8 to 1 ratio and haven’t had any issues.

The faint line is a guide for what we want the scarf to end as.

This is an example of an 8 to 1 ratio laid out on two ½” sheets of Hydrotek Meranti plywood we’ll be using for the bottom panel of the boat we’re working on now.

As mentioned previously, the Hand Plane method yields good result. Just use the plywood layers as a guide and keep everything nice and even. Once you’re just about to your mark, switch to a sander to help even things up.

Hand Planing Plywood for a Scarf Joint

All done. the layers are nice and even, and a little sanding with the block sander evened it out nice.

The Edges are set together with thickened epoxy
Clamped and weighted for the night
A nice, tight, joint, ready for sanding and any light fairing that may be needed.

With the Hand Router Scarfing Sled from Woodhaven we’re now able to scarf all the sheets for one boat. Set up with an 8 to 1 ration and a 2 ½” Planer Bit the scarfing jig makes nice scarfs. There is still some cleanup work to be done with a sander, but it sure is a time saver.

Here we are set up for two ⅜” sheets for the side panels and two ½” sheets for the bottom panel of one boat.

So, there you have it. While we can achieve outstanding results using the Hand Plane or the Scarfing jig, we are anxiously awaiting our next scarf and using the Shaper Origin for a precise CNC Lap joint and smooth finish.

Keep checking back for more of our journey building our Drift Boat company.

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