Carpentry/Power Tools/Sanders< Carpentry
The following entries apply initially to a single flapdisc system used to sand relatively small blocks for children.
Kids' block toys-- best construction and engineering educationEdit
Wood block toys are widely recognized to be the most versatile and most educational of all toys, yet they are surprisingly underrepresented in the armarium of toys and education devices available to children worldwide, with unfortunate results. Children are steered to toys from which one can learn little about how to do anything (music, math, engineering) but much about image, status and bogus conceptions of personal identity (dolls, similated weapons and other symbolic possessions, passive entertainment audio and video, etc. focused on the endless quarrel over who has the upper hand).
A recent Beckley-Cardy "education" toy catalog devoted less than 5% of its pages to wood block toy products—most of the rest consisting of plastic, paper, media etc. The block toy section offered, among other things similarly priced, a set of 500 blocks for $700($1.40 per block), guaranteeing that they are made of only the very best special New England maple and that every block is an exact precise multiple of the length or width of every other. (What does a 2-year-old care about wood pedigree?)
Forget spending all that money; buy a second-hand table-saw and a 7-1/4" carbide-tipped sawblade (which will last through hundreds of nailhits) and you can transform editable old scrapwood cutoffs from crates, pallets, construction and demolition leftovers, etc., into clean gorgeous blocks in surprisingly little time. Try to use what you find discarded in your neighborhood, or deadwood trunks and branches edited from local garden and street trees—the main priority is to trim and sand away dirt, pollution and splinters, leaving exposed the beautiful, infinitely instructive grain pattern, and round off sharp edges and corners.
There is no limit to sizes or shapes of blocks worth making for children, nor is exact geometry of importance prior to age 3 ("Irregular Blocks Teach Adaptive Engineering"). (Next to maybe writing symphonies for large orchestra, saw-trimming scrapwood into blockshapes for children is the most intellectually challenging and creative work on the planet.)
(Diagrams and pictures of representative products are in preparation to be added to the article, Wikiversity: Essential Preschool Part I. If you have a product idea with picture don't hesitate to add it there.)Tokerdesigner 22:29, 15 February 2008 (UTC)
Disc sanding systemEdit
Many sides and edges will have to be sanded to eliminate all chance of splinters, and round all sharp edges and corners on blocks destined for use by children. Attach a regular 1725-rpm motor to a table with the shaft pointing out over the table's edge. Onto the shaft, with an arbor/converter which can be obtained for less than $US10, attach a 7-inch flapsander disc (the #24-Grit "Tiger-Disc" for $18 from Weiler Abrasives is recommended, and other discs, from Grit #36 up, are often cheaper). This disc will survive tens of thousands of wood sandings.
As you face the sander with the block firmly held in both hands, the disc will be revolving counter-clockwise so that the direction is down on the left side, up on the right. Do all your sanding on the left side of the disc so that the dust flies downward into a sack, box or vacuum contrivance. Protective eyeware and woodman's muzzle (Muzzlewoodmanism) advised.
Instead of just holding the block still while pushing it against the disc, you want to keep the block moving so as to reduce heat-buildup (and clogging).
- Movement left and right distributes abrasion heat among different areas of the sandpaper and of the wood.
- Movement up and down varies the direction of cut (see below).
Develop a sequence of movements for sanding all sides and turning edges and corners. Mentally count numbers as needed to keep track of where you are in your system. Sanding a typical block from totally rough may take two minutes. (With hardwoods, you can save time by skinning the sides with a table saw or chop saw, leaving only sharp corners and edges to be sanded with higher grit paper.)
When rounding an end-edge, sand out of the sidegrain into the endgrain so you won't rip anything off (such as the bark on rustic pieces). Sanding blocks is analogous to conducting that symphony which someone else (maybe you earlier) wrote. It brings out the glorious artistry of the artist (tree), and will help you develop a systematic mind and sense of rhythm so that you are more effective demonstrating a Zooky (see Wikiversity: Essential Preschool Part I).
Some notes on strokesEdit
From much practice with the benchmounted disc system described above, the writer has learned to distinguish three types of strokes:
- Hyphen-stroke—left-right—used for low-pressure rounding of edges (usually four side grain and four side-to-end grain).
- C-stroke—a double stroke with the wood continuously in contact with the flapdisc 180 degrees around the left side of the disc and alternatively a little further toward the right at the top of the disc and a little further to the right at the bottom of the disc (illustration is in preparation and will be added to article). This is used for high-pressure sanding of flat sidegrain.
- I-stroke—up-down—used for sanding flat endgrain surfaces.
A stroke sequence found practicalEdit
1. Side grain: start with the block lying laterally with your right hand gripping the block strongly and ready to do turns, and your left fingers pressing the block against the left edge of the sanding disc, at a slight angle so that most of the pressure is against the outer edge of the disc. Sand about half the block with two high-pressure C-strokes (right-left-right-left), then turning the block "away" from you up to 45 degrees, two low-pressure hyphen-strokes, then again two high-pressure C-strokes on the original side, then turning the block "toward" you, two low-pressure hyphen-strokes. Do the complete operation four times in one smoothly continuous non-stop sequence. Then turn the block around and repeat the above for the opposite half of the block.
2. Turn the block so that it is slanting downward about 45 degrees toward the disc and rotate it so that each side-to-end edge is rounded; then turn the block end (crossgrain) flat against the outer part of the disc and do one or two I-strokes (see above); turn to 45-degree angle and rotate one 90-degree turn; again flatten endface against disc for one or two I-strokes, etc. (do the above four times).
3. With block lying laterally, this time about parallel to the whole flapdisc, grip strongly (for turning) with your left hand and with your right fingers press the block against the inner lip of the flapseries (at this position, nearer the center of the disc, the sandpaper is moving almost twice as slow as during the above sequences). Sand about half the block with two high-pressure C-strokes, turn it "toward" you for two low-pressure hyphen-strokes, and so on around (usually four times). Turn the block and do the other end-half similarly. This sequence is a little shorter than #1 above, and you are sanding in the opposite direction from #1.
4. Repeat #2 above with I-strokes on the endface, but this time against the inner lip of the flaps instead of the outer edge.
Depending on the size of the block, the above four-step sequence may take 1–4 minutes. In most cases, a softwood block handled this way is ready for varnish or paint, and a hardwood block for the next finer disc (with a shorter sequence). By turning and alternating you avoid overheating and use the disc most efficiently.
Varnishing is advisable to protect some softwoods which soil or stain easily, and it will make some pines, etc., more dramatic by bringing out the color contrast between hard (dark) and soft (light) rings. Select the boringest softwood pieces to be painted: first a coat of paint, then let dry; resand, possibly partly eroding the paint in an interesting grainy/drainy/trainy pattern; second coat may be varnish. Or paint the blocks with a light color, sand just enough for smoothness, give to children to draw or paint illustrations on, then final varnish.
An option with hardwood blocks is to resand with a higher grit (and at a slower wheel speed, which may require belt and pulley): Grit #36, #50, #60, #80, #100 etc. requiring 2/3, 1/2, 1/3 wheel speeds etc. The crossgrain thus revealed (detailed view of many years of treegrowth) is the #1 most educational view seen anywhere on the planet. Some pieces of especial beauty will need no varnish at all; others may be painted and/or varnished only on the side grain, leaving the final fine sanding of endgrain for after the varnish has dried.
Further learning bonus: sandman trainingEdit
Compared to saws, which scare parents, the sander is a relatively safe machine for relatively young children to use, making blocks for relatively younger children. Consult experts on how to set up a workspace in which some children can participate safely in this profoundly educating and productive performance art.)
Other small sanded-wood productsEdit
The above cited suggestions for sanding with the flapdisc system are applicable to a wide range of office equipment, tool handles, etc. where scrapwood-based product can substitute for presently available product made with new wood, petroleum plastics, metal and other less eco-friendly materials.
Most boards under 4'/1.3m are about as easily, and more cheaply, prepared with the disc sander system above, compared with a pricey handheld disc sander or belt sander, good as they are.
1. Stand facing the table- or bench-height 24-grit flapdisc and keep moving the board in a systematic way while pressing the board against the left side of the disc, mostly sanding crossgrain because though this may make the board slightly less flat the main thing is to kill splinters.
a. When sanding sides and edges at the left (your left) end of the board, hold most of the board securely under your right armpit and press with your left hand from behind the board.
b. When sanding sides and edges at the right (your right) end, hold board securely under your left armpit and press with your right hand from behind the board.
c. Sand at a 45 degree angle all the way around each end (holding the board pointing down 45 degrees toward where it contacts the sandpaper) before sanding the flat end. Rounding all edges will solve at least 90% of all splinter problems.