Pour coarse, polished stones or gravel into a clear glass vase. You want the gravel to fill the lower 2 inches of the vase. Glass beads also work well for this step.
Fill a sink or plastic tub with cool water. Place the orchids in the water so that the tips of their stems are completely submerged.
Use a pair of sharp pruning clippers to cut the stems of the orchids 3 to 5 inches shorter than the height of your vase (3 inches shorter if you want the orchids to float on the water surface and 5 or more inches shorter if you want them to float within the water).
Let the orchids soak in the water for 15 minutes.
Remove the orchids from the water and slip a metal washer onto the stems. The washer should hold the stems together but not cut into or damage the stems. Slide the washer up to about 1 inch from the base of the stems.
Wrap a rubber band loosely around the stems, just below the washer. The rubber band should hold the washer in place without constricting the stems.
Place the orchids in the vase so that the stems penetrate the layer of stones, gravel or glass beads and the washer rests on top of the layer.
Add an additional 1 or 2 inches of coarse gravel, fine gravel, polished stones, glass beads or sand on top of the washer. You can even use seashells as long as the shells are heavy enough to keep the washer in place.
Fill the vase with distilled water. Fill the vase to just below the orchid blooms if you want the orchid blossoms to float on the surface of the water or fill the vase to 1 or 2 inches above the orchid blossoms if you want the orchid blossoms to float within the water.