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- For lid: slab approx. 3" x 5"
- 2 slabs each for sides and ends cut same as lid
- 2 slabs for bottom and inside lid, cut 3/8" smaller than lid
- Permanent marker
- Trim saw
- Flat lap with grits or diamond compound
- Tri-square
- Wood or aluminum block cut with a 45° angle
- 330 epoxy
- Water soluble wood glue
- Plastic wrap
- Single-edged razor blade
For information on supplies, please see the Annual Buyers' Directory.
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STEP 1.
Select your material. Material that has an even all-over design doesn't need to have the corners mitered, but materials with a definite light/dark design, e.g. "chicken track," picture rock, jasper/agates with dramatic color changes and stones with attractive lines will be enhanced by mitering the corners and matching the patterns. Stones such as labradorite, for which orientation is necessary, will also benefit from mitered corners. Banded agate or onyx and 3-D intarsia patterns make beautiful boxes.
STEP 2.
Cut 3-5 slabs back-to-back from the same rough, making your slabs 3/16" thick. You could also "butterfly" 2 slabs and double the side of your lid.
You will also need 2 slabs of same or different material for bottom of box and inside lid.
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STEP 3.
Lay out your slabs. First select the slab that you intend to use for your top. This will determine the size of the box. It is important to select slabs of the same thickness for the sides and the ends of the box. Uneven thickness will cause gaps on the inside of the box at the mitered corners.
Use the trim saw to cut slabs to size. If available, an overhead drop saw is preferable - especially for larger boxes - in order to rough out the pieces, cutting close to the lines.
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STEP 4.
Identify the outside and inside of each piece. Match the pattern on the lid to the sides and ends, and mark the inside and outside of each piece with permanent marker.
(Note: Arrows shown = bottom of box) |
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STEP 5.
Lap the outsides of each piece so that they are flat and can
be placed back-to-back perfectly. Using water-soluble wood glue, glue the outside faces of sides together. Lap the ends and sides to fit the size of the lid (if a little smaller, you can adjust the size of the lid, but watch your pattern), making sure they are square. |
STEP 6.
Lay out the material for the bottom of the box and the inside
of the lid. As you did in STEP 5, lap one side of each and glue together. Lap to size, squaring carefully. The bottom needs to be squared with vertical sides, but the inside lid should be beveled to soften the edges. |
STEP 7.
Lap through the grits, then polish all exposed faces (these will all be inside faces of the box). Be careful to rotate the pieces during lapping to prevent wedging (especially if you are cutting a soft stone, such as onyx, marble or chalcopyrite). |
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STEP 8.
Separate the glued sides and ends by soaking in hot water for 12 to 24 hours. I usually soak the pieces in a covered Pyrex bowl in an oven set to about 150°F. Sometimes it is necessary to raise the temperature to 180° or 200° for half an hour or so. Slide the pieces off of each other. Do not try to pry them apart. If necessary, raise the oven temperature again. (Leave the bottom and inside lid together at this time.)
STEP 9.
Now for the tricky part: mitering. I do it all by eye, first marking the miter angle with permanent marker using the 45° angle of the tri-square. Then glue all 4 pieces, with polished surfaces facing in the same direction, lining up the miter lines. Lap until you have a 45° angle, checking with the tri-square. The only jig that I have is a wood or aluminum block carefully cut to a 45° angle. (I'm sure there is someone out there who could make a much more reliable jig.) The block is to help with the final adjustments.
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STEP 10.
Adjust the sides and ends to fit the bottom and the inside lid (which are still glued together). Hold the sides and ends in place around the bottom and the inside of the lid. If the sides hold and lift the bottom, you have a good fit. If not, minor adjustments may be needed to either the bottom or the ends and sides. This is where the wood or aluminum angled block comes in handy -- you can place it on the lap and use it as a jig.
STEP 11.
Separate the inside lid and bottom. Use a suitably sized block to support the inside lid just below the rim of the box. Rough up the bottom 3/16" of the sides and ends, using the masking tape to protect the rest of the polished surface. Using 330 epoxy, mix equal parts very well and smooth a small amount on all surfaces to be glued. (Excess glue is very hard to remove from the inside.) Carefully assemble into place. Wrap plastic wrap around the polished face of the inside lid and insert, supported by the block to prevent the sides from leaning in and to hold shape. (This also ensures that the inside of the lid will fit.) Secure tightly with rubber bands and let site for at least 24 hours for the epoxy to set.
STEP 12.
Polish the inside of the lid. Rough up the center surface, leaving apporx. 1/4" polished surface around the edge. This creates a better bond. Glue the inside lid to the lid and place inside the box for position. Again, use the block for support and wrap with plastic wrap to prevent the epoxy from gluing the lid closed. Hold with rubber bands. When the epoxy is dry, remove excess with a single-edged razor blade. Holding the lid in place with water soluble glue, lap and polish all surfaces.
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