Disclaimer: Regarding the tools and equipment I used in this process: I have used them in a manner inconsistent with the manufacturer's intended use. As a result, naturally, the risk of injury involved in their use is increased. If you choose to follow this process, please understand that you do so at your own risk.

Feather rock (FR) is a type of lava rock. Kind of like a volcanic glass. It can be very sharp. While working with this rock, it is possible to get a "splinter" from it. While using power tools w/ it, some of the material may go flying through the air. The use of safety glasses is strongly recomended. $10 spent on safety glasses is cheaper than having a splinter pulled out of you eye at the ER, I know this from personal experience. Gloves will protect your hands from cuts, scrapes and the general sharpness of the rock while handling it.

FR can be bought at most landscaping stores or at stores like Lowes or Home Depot. Most rock is sold by the pound. FR comes in a couple of different colors, as leaset that I have seen. Some of it might also have a vein of a different type of rock in it as well. It would probably be a good idea to test a piece of the rock before putting it in your tank. FR can probably hold a pound or two of water, so buy it when it has been dry for a few days.

Some of the tools that you will need are: A saw of some sort. I have used a bow saw (tree trimming type), a used 1 1/2" band saw blade about 18" long or a long saw blade of some kind. A drill with carbide tipped concrete bits, I have even used old wood "spade" type bits. Optional tools can include an ice pick, scratch awl or possibly even a long nail, a flat or round file, large and small diameter bolts (used to open up and shape holes). Gloves will protect your hands. Wear old clothes and work outside. Please keep in mind that some of these tools were not meant for cutting or cutting into rock. Using them in this manner will either dull them significantly or possibly even ruin them.

Put on your safety glasses. Look at the rock a decide which is going to be the top and then turn it on its side. Whenever you try to start a cut, push the saw blade so that the tips of the blade are not digging in to the rock at first. When a line has been started, just keep pushing and pulling the blade until that part of the FR has been cut off. Photos #'s 1 & 2. If you want to fit it into a corner like the one here, set the FR on its bottom and saw off the left and back sides to create a 90 degree angle so it'll fit into the corner. Photo # 3. Keep the pieces that you have just cut off. They can be used to make in the tank backgrounds. If the FR doesn't sit they way you want it to, rub it on some concrete to take down some of the rock to make it sit how you want it to.

Once you have the FR the way you like it, turn it over on to the top so the bottom is up. Put a fairly large concrete drill bit into your drill and start to drill some holes along the perimeter. Start fairly close to the edge, about 3/4" away. Drill holes all the way around the rock, as close together as you can. Try not to go all the way through. Keep in mind how thick the FR is where you are drilling (it might be thicker or thinner at other parts). When that is done, try to connect the holes that you just drilled. Insert the drill bit about 1/4" into a hole and then lean the drill at an angle so that you will drill into the hole next to it. Do this all the way around at one angle and then again (if necessary) at the opposite angle. The purpose of this is to cut away as much material as possible so that the piece in the middle will break out easily. Keep drilling material out until you can get the middle piece out. Photo's #'s 4, 5 & 6. If you happen to go through the FR all the way, you can use this hole as your first entrance to the cave.

The way that I smoothed out the inside of the cave is by using a spade bit in the drill. I wedged the FR between a couple of things that will hold it in place. Pull the trigger on the drill and use the side of the bit up against any part of the inside of the FR that you don't want there. Rub it along the inside walls untill it is as smooth as you want it. Go slowly. The bit will probably bounce off the walls some. Go slowly until you get the feel for this. Photo # 8. Don't take off too much in one area or you might go through the rock, like I did in photo # 9. Photos 10 and 11 are the same rock. The pictures were taken one in the sun and one in the shade.

Once you have the inside the way you like it, turn it over and lay it flat and figure out where you want your first entrance. Turn it over and drill a hole in that spot all the way through. Photo # 9 shows where I went through the rock by accident. This is where my first hole will be. I opened the hole up using a large and small bolt (use the threads like you would a file) and scratch awl down to the point at where the pointer is. File the hole into the basic shape that you want. Take off any really sharp, pointy areas that might hurt a fish. Use a large bolt to make larger openings and a smaller bolt to make smaller ones. Use a scratch awl or nail and scratch away at the rock and create an opening. Make a few more entrances into the cave if you want. Get some sand paper, about 60 or 80 grit, and sand down the rock. This will make it so that the rock is a little less sharp.

The next step is to prepare the cave for the tank. If is just washed and put into the tank. the FR might float somewhat. You can attach a piece of slate to the bottom to keep it on the bottom of the tank. One other thing that you can do is to boil the FR. Boil the rock for a few minutes. Using tongs or oven mitts or something to protect your hands, get the rock out of the water and put it directly into cold water. Let it soak there for a few minutes. It should now sink to the bottom of the tank. I am not positive, but I think that this process forces out the air bubbles that are trapped in the rock. Not only that, but boiling it should also kill any organisims that are living in the rock. That's it. There really isn't much to it. It is fairly easy to do. Just make sure that you are wearing safety glasses. □