Bent Wood or Curved Shield Making

by Thermopocles

Introduction

So you want to build a bent wood (or curved) shield. Well, cheer up, it's not as hard as you have heard! It is more time consuming than you might imagine, but there is no magic involved, just some patience and a good helper. Just what is a curved or bent wood shield anyway? Usually, it is two pieces of wood (plywood) glued together to from a curve, usually around a vertical axis.

You will need to get your tools and materials together ahead of time. Then you can proceed. There are many steps to producing a curved shield: pattern making; lay-out and rough cut; preparation and set up for gluing; glue application and actual lamination; curving and curing; take down and finishing.

Tools and Materials

You will need the following "tools": a rubber mallett; a stout tree at least 20 or so inches in diameter (or an appropriate barrel or other object); rope enough for three to five times (with lots of slack) around separately; a good sized friendly helper; several small "C" clamps (I've worked with as few as 3, but the more the better!); a handful of wood and spring clothes pins; a work surface (and old newspapers for glue up time); a saber saw or band saw; scissors, pencil, masking tape (or duct tape); and a cheap paint brush. You will also need the following materials: A/C-X quarter inch plywood or luan-- enough for two shield shapes with plenty of margin on all sides; glue-- "Titebond" works best, but "Elmers Carpenters Glue" (yellow) will do; rags; poster board.

Pattern Making

This may seem a trivial step to some. It is a time saver though, even if you only make one shield to this shape and size. You have to cut two mirror images from the wood; with a pattern, you only have to do your layout once. If this shape and size shield work well for you, then you have saved even more layout time on future shields. Gather two or three sheets of poster board, scissors, and tape. Don't be afraid to tape two pieces of board together to make a long kite or heater. In fact, using the tape and scrap board eradicates the tragic loss of cutting too much from an almost finished pattern. Just tape a few scraps back on, redraw the pattern and cut. This allows you to experiment and change your design. You will also find that your shield can be a good deal smaller than you thought. I have found that a width of 22 or so inches is a large shield for even someone of my girth. You can get both parts of a quite large war shield (read "door") from one piece of 4x4 plywood.

Draw and cut your pattern to the final shape you want your shield to be. The rough cutting of the plywood will require lots of margin.

Rough Cut of Both Shield Pieces

After you've finished your pattern, examine your plywood, not all plywood is alike. Most plywood and luan bends or flexes easiest in parallel with the grain direction of the outer plys. Use your knee or a tree or door facing and flex your material both with and against that grain direction. You want to lay out your cut lines so that the shield will be bent in the "easy" direction. This is actually the stronger and longer lasting method. Lay your pattern on the plywood at least 3/4" from any edge, leaving plenty for a duplicate. When you get the pattern oriented correctly to the grain, then tape it down in a couple of places. Now here comes the critical part: neither piece will be traced off directly! Margins must be included! Lay out the outer piece first, as it requires the largest margin. The outer piece requires at least a 3/4 inch margin on each side and 1/2 inches on top and bottom. Those are minimum measure margins and are geared to a 3/8 inch all around margin for the inner piece. If your inner piece margins are larger (I would suggest at least 1/2 inches for your first effort) 1 inch for each side and 3/4 inches for top and bottom of the outer piece on your first is not at all too much.

With the pattern taped down, mark the wood every few inches at the appropriate "MARGIN" distance. Do this for both pieces and be sure to label them inner and outer. One trick of the trade is to "flip" the pattern over to get mirror images on the two mating surfaces. This must be done if your design is not symetical. I have found it best to use the two "c" sides as mating surfaces and keep the two best sides out. Another hint: If you are using a saber saw, lay the patterns out on the "c" side; if you use a band saw, lay them out on the "a" side. This is not critical but makes for nice cuts. Now remove the pattern and with a soft pencil or marker, connect the margin marks. Cut on these lines; if you are a little fast and sloppy, that's ok; just so you are close to the lines. Be sure the two pieces are labeled inner and outer. Now comes that time! You are ready to glue up.

Lamination

Now pray for two to three days of no rain or light rain, over 45 degrees F overnight low temperatures, and a large patient friend. Now select exactly where on the tree you will tie the shield lamination when you are ready to do so. I am lucky to have a tree with several nice radiuses and a convenient indentation in the back side. This indentation comes in handy for tightening and re-tightening the ropes. You can tack a couple of 2x2's the length of the shield to be about 10 to 12 inches apart on the back side of the tree (1x2's will probably work just as well.) These allow you to work with the rope when retightening.

When your prayers have been answered, and the time is right, the actual laminating process won't take over forty five minutes. First, your ropes should have a loop in one end and be long enough to reach 1 and 1/2 times around your "tree". You'll need at least three; enough to space them about every 8 or 10 inches. Lay the shield pieces glue ("c") side up on newspapers (or just use a couple of milk crates or garbage cans). Pour on the glue and spread with the brush on both pieces. Put a good solid coat on. Now take the "outer piece", flip it over (glue to glue) and position on the "inner piece". Pick up the entire unit and position on the tree (sometimes a third friend here helps). Holding the pieces on their sides, push in to the tree and you get some curve to the shield. HOLD this position till your helpers get a couple of ropes around. Everybody has their own favorite knots, but I'm lazy; I just run the loose end through the loop and secure with a simple half hitch. However you tie it, remember that for the next few minutes you will be loosening and retightening each of the ropes. Use the loop like a pulley to take up the SLACK (not to tighten the shield). Using the rubber hammer, tape the sides of the outer piece and keep it over-lapping the inner piece. Get all of your ropes on, and evenly spaced. Now its time for the biggest one present to earn their keep. Repeat the following sequence until you get the desired curvature. Have the largest or strongest person push on the sides of the shield against the tree; cinch down the ropes in an even manner starting with the lower ones. Rest and repeat as necessary. Don't forget to keep the outer piece overlapping the inner piece, using the rubber mallet.

Now, take the "C" clamps and secure any gaps in the edges. Use what clamps you have on the worst gaps first. Take the clothes pins and space them around the edges, as needed. If there is any chance of rain, take some plastic and tuck into the top with a couple of extra clothes pins. Loosely secure the bottom.

Now It's Miller Time!

With an appropriate refreshment in one hand and a wet rag in the other, wipe off any excess glue from the front of the shield. Then let the glue dry at least 24 hours in dry weather, more in humid conditions.

When you are sure the glue is completely dry, take it down. Lay your pattern on the shield lamination, (inside yields another 1/4 inch in width; outside is easier); tape it down in a couple of places and trace off around the edges. Cut your shield out: Go slow and use a fine blade for the least splintering. You will probably find a few gaps in the edges. Fear not! This is the time consuming part. Just pour some glue in the gap and close it with "C" clamps. Let it set for another 24 hours. If you have only a few "C" clamps like I did, the above will repeat over several days. This is the time to begin block sanding the edges (slightly rounded corners); handle and strap making and mounting; etc.

You are now on your way to having and using a nice but strong curved shield. Those of you who prefer metal edging on their shields should try aluminum "Paldsters" (shelving aids) from a building supply store. In the distant future, I will write a short article on finishing and painting shields.