Sand, like water, is a fluid material that kids will configure as their imaginations dictate. But if castle walls, riverside piers, or Matchbox-car garages are to be much more than shapeless humps, young builders need something rigid to form or reinforce walls, platforms, and roofs. Plus, the children need mobile sand toys to carry their imaginations through the formed media.
Long, narrow wooden blocks are better for reinforcing sand castles than conventional squares and rectangles. Wooden wheeled excavators and trucks are good to move the sand around. Plus, they will float to serve as boats, barges, bridges, and rafts on the water table.
I made sand blocks and toy sand movers from wood scraps: hardwood left over from furniture projects and softwood from building-materials cutoffs. If you make a water table (See "Build a Water Table for Kids") you'll have a few feet of 2" x 3" and plywood left over you can use. If you don't have a shop of your own, see if you can salvage leftovers from a local lumber finisher, a commercial furniture maker, or a neighborhood woodworker. Check building sites for ends of 2-by framing lumber and other scrap. You might see if local hardware stores, supermarkets, outdoor sports, or camping goods outlets, or roadside stands sell wood stove or vacation camp fire kindling. Stores near me sell plastic-wrapped packages of assorted factory scrap hardwood for $3.00—expensive to start a fire, but far less than you'd pay for the equivalent board-footage of raw building stock.
Or, buy a few lengths of good clear 2" x 3" or 2" x 2" lumber, some 4/5" x 4" decking-board stock, and several feet of square, round, slat, and L-shaped hard pine or poplar trim stock, and saw it to length. I have an electric cutoff/miter saw that produces square ends automatically and quickly. You can get the same result at less cost with an inexpensive plastic miter box and muscle-powered backsaw.
Sand Building Blocks
To prevent splinters, choose close-grained, well-dried wood that is hard enough your thumbnail can't make much of a dent in it. For sand pit or sandbox play, cut any size board from a 2" x 4" stud to 1/2" x 2" wood lath or 1 1/2"- or 2"-diameter dowel into 4", 6", and 8" lengths. Much smaller blocks disappear in sand. Larger blocks are out of sand-castle scale and too easily become kid weapons when the inevitable squabbles erupt. Sand all blocks well, especially ends rough-cut across the grain. At minimum, seal with a coat or two of deck sealer. For more elaborate finish options, see below.
Strips of plywood will be used to make roads, roofs of buildings, and walls. Make up a bunch—4" wide and 6", 8", and 10" long. Raw plywood will warp and delaminate in the weather, so soak it well in a hard finish.
I made up a bunch of simple earth movers. Each represents a different combination of construction options that you or your kids can mix and matc.
Bodies were made from 2" x 4" or 2" x 3" softwood or by gluing and clamping strips of hardwood or plywood scrap and sanding so joints largely disappear. I used Titebond waterproof glue, a "space-age" indoor/outdoor wood adhesive that requires no mixing as does epoxy.
Using a Forstner bit that produces straight-sided, flat-bottomed holes, I drilled bodies to accept those little round "peoples" that come with several brands of wheeled toys ...or you can turn your own if you have a lathe.
You can also make your own wheels on a lathe, or using a circle cutter on a drill press or a hole saw on your portable drill. Ready-made wheels in several designs and sizes are available at craft and hobby stores or from the mail-order catalogs that advertise in woodworking magazines.
Between painted or varnished bodies and wheels, I inserted enough fiber washers to prevent rubbing.
The following are brief explanations of how to piece together a few models, but there's room for versatility of design, so feel free.
Pusher The body of this minidozer is made from a block of 2" x 3" building stud, the blade from 1/2"-thick hardwood. Three sets of wood wheels are fastened with waterproof wood glue to 3/8 dowel axles. Axles are set into grooves carved into under-body and held on by a hardwood strip fastened with rustproof wood screws. No drilling (or drill) required, and easy to make and repair. Finish is minimal and intentionally rough: two coats of deck-sealer (sanding between), to accept a child's crayons or marker, yet clean off reasonably well.
Scooper Joints are screwed and glued except for the scoop, which is made from thin, oak box-making stock (or plywood) and joined with dovetails made by eye with a coping saw with fine blade and a 1/4"blade hand chisel (easier than you think—try it; just keep the chisel razor sharp). For strength, hardwood fillets (from the flying model or doll-making section of a craft supplies store) are glued at inside corners of scoop. The wheels are held on by 3/8" wheel pegs glued into 3/8 holes drilled in the body. Gives the best-finished look, but the peg axle is relatively fragile and difficult to repair. To show off the joinery, parts are stained with contrasting colors, glued sparingly, filled, and spray-varnished to a craft-store shine.
Hauler Made with a 2"-3" softwood body with plywood base/bed. Wood wheels of this flatbed truck are held on with short 1/8"-shanked brass wood screws set into pilot holes drilled into hard dowel plugs that have been glued into holes into the softwood truck body. Be sure to use screws with round heads, as tops of flathead screws have sharp edges. Parts were filled and painted before final assembly, then, were given a several coats of clear.
Roller Body is made of three strips cut from a 9/6" x 2" strip of white oak scrap, notched to accept wheels, and laminated together with glue and brass wood screws. The fat, turned-maple wheels are attached with 3/8" wooden wheel pegs. The example pictured was left natural, filled, sanded, and sprayed with several coats of clear acrylic to produce a craft-store finish.
Decorating and Sealing
Most children have to be discouraged from marking or coloring on toys—especially on smooth, carefully varnished, inside-use wood blocks and rolling toys. Our blocks are for outdoors, however, and I find that kids adore being allowed, even encouraged, to use crayons, markers, or paints to turn the building blocks into girders (or magic wands) ...and to draw spokes and mufflers (or a flowered border) on the wheeled earth-moving toys.
Probably most satisfactory to most young children is for you to soak the wood in a colorless outdoor sealer (made for decks), and let the children do a quick finish sanding and then decorate with water paints, crayons, or washable markers. The colors will wear off quickly, and I've found that the kids will get the urge to redecorate several times over a summer.
Some kids—mainly boys aged 6 to 8 who are future high school Wheelheads—love vehicles with wheels that leave aggressive-looking tread marks in moist sand. You can give your tread-maker a narrow-edged wood file and let him make grooves or notches or crosses in the wheels of his favorite sand vehicle to leave personalized "treads." Black marker will give tires a satisfying color.
Exposed to a summer of sun and rain, unfinished wood will weather to a mottled gray that isn't very attractive to an adult eye, but doesn't seem to reduce play value to the kids. Bring the blocks and toys in come fall, hose off the sand, bleach with diluted Clorox or a wood bleach, and store till next winter—when you and the children can refurbish them.
Refinishing or rebuilding the sand toys can be a powerful hint of warm weather to come and become a late-winter family ritual much like carving pumpkins on Halloween. Our kids would get all excited, bundle up in snowsuits and boots, take the wooden toys out to the sandpit (still buried under a yard of snow), play with them in the snow for a while, and—of course—leave them buried there. So long as we kept the dogs from carrying the good-chewing wood blocks off, building blocks and sand movers would sink as snow melted and be in place and ready to excavate when the weather warmed in the spring.
A few fastidious young ones and many older kids who are developing a precocious sense of order will resist marking on toys or having toys that look "dirty." For them—or to satisfy your own sense of order—you can give the blocks and toys a better finish. Easiest is to assemble toys, then preserve the wood in one step with several coats of outdoor wood preserving sealer/stain. For a better job, before assembling, sand the wood smooth—slightly, rounding only those sharp corners that will be exposed after assembly. Treat exposed faces with several coats of a good sanding sealer (sanding lightly between coats). Spray parts with several coats of nontoxic exterior-grade enamel, truck bodies in bright colors, and wheels in black or bright with black tires. Assemble and then, for a toy-store finish, spray with thin coats of clear outdoor acrylic finish.