THIS IS PAGE FOUR       The Methods, making a slate aquarium decor by slotting slate.

PAGE ONE  Where to find slate suitable for aquarium decor.

PAGE TWO      Is all slate safe in aquariums?

PAGE THREE     Tools needed to make slotted slate aquarium decorations.

PAGE FIVE       The Designs. Some basic structures for building with slate in an aquarium.

Nipping, knapping, breaking and snapping. Shaping the slate pieces for an aquarium display should be the fun part.

Hitting a slate tile with a hammer will allow the forces of accident into your design process. In other words, You will be presented with shapes that might trigger ideas for an exciting arrangement. If you are searching out your slate pieces at a quarry or roadside excavation, the array of shapes and sizes or one particular shape might stimulate your imagination and ideas for how to arrange the slate in your aquarium.

On the other hand, you may have a pretty clear idea of what you want and where in the tank you want it. If you do know the size and configuration of the aquarium decoration or sculpture you hope to build, the most sensible and ultimately time saving thing you can do is to take the time to find pieces that are close to the shape and size you want in the first place. This may sound obvious but locations that offer a huge selection can be overwhelming. The tendency is to take more than you need and select later but this can lead to more work in the long run if your selection is missing one or two pieces of a particular size and thickness. Taking the time to choose slate pieces that are equal in thickness will give you a lot more choice and flexibility when you get to the fitting together stage. If you try to work with slate pieces of varying thickness you will have to custom cut each slot and if one piece should break, the piece it was intended to fit with may also be useless. 

Tips on Splitting Slate for an Aquarium

It should be noted that most slates have a grain that is in many ways similar to the grain in wood. In many types of slate the grain is easily detected by ripples, specks of colour etc. flowing in one direction. If the grain is very evident , most likely, the slate will break very easily along the grain and be impossible to break across it. Other slate types have less clear signals, are brittle and much less predictable. Anybody who has split some firewood with an axe will understand the effect of the grain. An axe that easily divides the wood along the grain simply makes dents when hit across the grain.

There are two purposes for splitting aquarium slate pieces. One is to split the slate piece entirely so as to produce two or more useable pieces. The other is to split away a particular section so that it is thin enough to be nipped into shape. Both involve using the same tools, a sturdy bench or block, a blade and a hammer  But the hand actions differ.

Splitting pieces entirely requires carefully tapping a groove along a substantial amount of the perimeter edge. The groove needs to be parallel with the layers of the slate in the center of the edge. In other words, thick pieces can be split into two sections of equal thickness. If the resulting pieces are thick enough, they can be split again into another two equally thick sections. Attempting to split a thin piece off the surface of a thick chunk will almost certainly fail. If one or more of the edges are sharp, you will need to either break the sharp edge off with a hammer or make a preliminary cut with a saw so that you can position your splitting groove along the center of the edge without having the blade slip off.

When you have tapped a groove around the edge of the slate, you can attempt to split it open with harder blows from the hammer. Some slate types split very easily, others much less so. Don't hammer the blade into any one part of the groove, you need to equalize the depth of the groove, moving the blade from one part to another. When you see that the slate piece is starting to split, you can hit harder. Your hardest final blows need to be along the grain of the stone.

The splitting technique that thins the stone for shaping requires sharp hits without making a preliminary groove. Position the plane blade on the edge to be thinned. It needs to be parallel with the layers and slightly less than halfway into the edge. The bevel on the blade should facing away from you towards the center of the edge. A sharp blow should shear off some layers along that section of the edge. Move along the edge of the area you want to thin with repeated sharp blows. This method can also be used to add interest to the surface of your slate by splitting back sections further than the finished edge.

Tips on Shaping Slate for use in an Aquarium
(Nipping and Knapping)

So what is the difference between nipping and knapping? Nipping needs little explanation. The shape of the slate piece can be altered by taking small bites from the edge of the stone with, what else, nippers. Nipping away the edges of a slate rock is about as far from rocket science as you can get. There is not much that can go wrong. The only thing to remember is not to attempt too large a bite. Always position the nippers so that one end of the nipping blades is very close to the existing edge. If you attempt a large bite with the nipper blades in line with the grain of the slate it is possible for the nip to extend and travel across the entire piece of slate. If the slate is too thick to nip, try splitting it away as described in the previous section.

Knapping is the process of altering the shape of slate or other flat stones by hitting them along the edge with a hammer so close to the edge that the underneath surface is broken back. Turning the stone over and repeating the hits breaks back the other surface. This was the process used by stone age man to shape and put sharp edges on axes and arrowheads. Of course, in an aquarium you don't want to have sharp edges so be sure to dull them by dragging a metal blade across the edges at right angle to the edge if you use the knapping technique to alter the shape of your slate pieces. Breaking back edges by knapping works best if the slate piece is held with the slate at a 45 degree angle with the edge that is to be broken away resting on the hitting surface. Accuracy is called for. Hitting the slate an inch or even less away from the edge is likely to result in the slate being broken entirely. This is a fast and efficient way to shape slate pieces once the technique is mastered.

Tips on Sawing Slate for an Aquarium

You can use specialized handsaws to saw slate. They are called Rod Saws. The blades are made from a thin steel rod coated with abrasive material. There are no teeth as such so they cut with both the forward and backward movements. The blades fit into hacksaw style frames so usually there is a method of tightening the blade. This is needed occasionally as the rods stretch with use. The blades need to be tightly stretched but it is possible to over tighten them and so cause them to snap. They can also snap quite easily if they are worked too fast and get hot from the friction. These blades do not rust so they could be used under a trickle of water to keep them cool.

You will find sawing slate with a handsaw much easier if you hold the slate very securely. A clamp or grip with rubber jaws will really help especially when making cuts for slots. Clamp the slate with the section into which you want to cut your slot overhanging a table and make cuts towards the table. When you are making cuts to produce a slot you will need to make two parallel cuts close together. Always make the cut closest to the edge of the stone first. Otherwise you will be making your second cut along a narrow section of stone that is very liable to break as you make your cut.

Clamping the slate securely is even more important if you intend to use a handheld circular saw to make your cuts. Unfortunately, when working with small scale pieces of stone such as you would use in an aquarium, positioning a clamp that holds the slate firmly but does not get in the way of the saw is difficult. A piece of slate may feel firmly clamped. However the blades on these saws turn very vigorously at up to 1200 revolutions per minute. In a hand held situation the blade can easily grab in the slot which in turn can cause the slate to break with unpredictable consequences. For this reason I do not recommend using circular saws to cut slots in small aquarium sized slate pieces. 

The power saw I do recommend is no less powerful and no more expensive. It's a small table saw designed to cut ceramic and natural stone tiles. These saws have a tray of water beneath the tablesaw surface which keeps the diamond coated blade cool. This type of saw gives you a lot more control. Instead of having to clamp your slate piece, you hold it in your hand on the table saw table surface and push it into the fixed revolving blade. Try to get a blade that does not have indentations. A smooth blade without holes or cuts will not hurt your hands if you touch it while it is turning. Keep the water tray topped up, you can pour water into the tray past the blade at the saw table surface. The saw has a blade cover that directs the water that is spun up by the blade back down onto the cut. However there is probably going to be water spray and dust if the water runs out so it is work that should be done outside rather than in the kitchen. I find it easier to stand at the side of the saw and slide the slate piece sideways into the blade. In that way I can avoid getting sprayed, and the vision is better.

To make slots you need to make two parallel cuts. Always make the cut closest to the edge of the stone first. Otherwise you will be making your second cut down a narrow tongue of stone that is very liable to break when you make the second cut. Keep the saw blade running straight in the cut. Twisting the slate on the blade while the saw is running will cause the blade to grab and probably break the stone. Cutting slots in the slate requires that you push the slate into the blade and then pull it back again. This return movement has to be done carefully, straight back with no twisting. It's a good idea to practice cutting slots into some scrap slate. You can switch off the saw and let the blade stop before pulling back if you really have difficulty. Once you have the two parallel cuts you can break out the central tongue by inserting a flat screwdriver into the slot close to the end of the cut. A slight twist of the screwdriver should break out the center.

Use a brush to wash your freshly cut slate pieces in clean water as soon as possible. Cleaning the slate will be more difficult later If you leave the sediment from the sawing to dry on the stone.


PAGE ONE  Where to find slate suitable for aquarium decor.

PAGE TWO      Is all slate safe in aquariums?

PAGE THREE     Tools needed to make slotted slate aquarium decorations.

THIS IS PAGE FOUR       The Methods, making a slate aquarium decor by slotting slate.

PAGE FIVE       The Designs. Some basic structures for building with slate in an aquarium.



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