How I built my Greek aspis (hoplite shield) - step by step photos

[PygmyHippo]

   

I bought 1/2 inch, 4x8 feet sanded birch plywood, and cut it to 36.25 inches while I was still at the lumber store to make it easier to handle, since I knew no piece would be needed larger than 36 inches, but still giving me an extra 0.25 inch to allow for kerf and sanding.

   

I measured the ring widths in the cross sectional paper diagram I made, transferred those rings over to the plywood, and cut them out. Obviously several rings can be cut out of a single piece of plywood if you draw additional rings within each other. Drawing a cross section helps to immediately identify which rings nest inside each other. Once I drew each ring I labeled the ring so I would know in what order it would fall in the glued stack (though it's pretty obvious when you're stacking them). I ended up with 11 layers.

Here is Matt Amt's diagram he used. I used a slightly different curve for mine, as well as 0.5 inch wood rather than the 0.75 inch he used. 
Matt Amt - Cross section of aspis
http://www.larp.com/hoplite/aspis5section.jpg 

My drawing has a bunch of scribbling on it, and dimensions changed as I was transferring the measurements, so it might not be overly helpful to you, but I'm including it for the sake of completeness. I started by just drawing a freehand curve of what I wanted for the dome (the red pencil), measured 0.5 inch (12mm) slices (purple marker), and then estimated how wide each ring needed to be based on where the red and purple lines intersected, and took my measurements from that.

   
   

There's alot of waste left over after cutting out the rings. Most of it went in the kindling pile.

   
   

I tested the stack to see if it was looking the way I planned in my cross section. All looked well so I started glueing.

   

I glued the layers in 3 batches: the 2 pieces for the rim, the first 4 layers, and the top 5 layers. I used wood glue with a reasonable working time to reposition if needed. I used Titebond wood glue. There were faster-drying options that had better ratings for outdoor use, but there were 2 reasons I didn't choose that. The first was because I knew that regular wood glue will bond fabric perfectly well from previous experience, and I knew I had to do alot of fabric glueing. The second reason is because I knew I would be coating the shield with many layers of paint, and the wood would be very well protected from moisture.

I used a combination of wood clamps and weights to hold the rings tight while they dried.

   

I let the 3 batches of rings dry for 24 hours, then glued the 2 sets of rings for the bowl together, and let those dry for 24 hours. I kept the rim ring separate at this point since it would be much easier to sand the exterior of the bowl and to bevel the rim if those pieces are separate until the exterior sanding is complete. Chris B.'s videos on YouTube help to demonstrate all of the sanding inside and out for the aspis and the rationale for handling the rim seperately. Be sure to check them out. 

Chris B. - Aspis Construction - Sanding Outside Bowl
https://www.youtube.com/watch?v=CDVqg2KEyag

I stacked alot of bricks and weights on them, and let this next group of rings dry for 24 hours.

   

Once the glue was cured, I started sanding the outside of the aspis with an electric belt sander using a 3"x18" 36-grit belt. Again, refer to Chris B.'s videos on YouTube. Keep the sander moving with the curve of the shield, and in slight side to side movements. That way you avoid gouging with the edge of the sanding belt. A 36-grit belt is best for this task. 36 takes off material the fastest, and since the bowl will be sanded, then puttied, then sanded again, then glued, then covered in fabric, then given a couple coats of paint, you will not see any difference using finer grit sanding belts. All that will happen is you'll sweat more, expend more time and go through many more belts.

This is definitely an outdoor job. It was 93° F (33.8° C) and 100% humidity when I did the sanding. Yuck! I always wear eye protection when using power tools (and you should, too) but it was really hard to see what I was doing through all the sweat collecting in the goggles. Even with a dust bag and vacuum attachment this process creates a ton of dust. Wear a mask and sand outside. If you attempt this indoors I'm not responsible for your inevitable divorce.

It took around 2 hours to sand the convex side of the shield.

   

Using some bricks or blocks to elevate the shield off the ground or work surface is important so that your sander can reach all the way to the edge for a smooth transition. Yep, Chris B.'s videos cover this perfectly.