Handyman will find aluminium easy to use

Press, 12 February 1986, Page 36

Handyman will find aluminium easy to use

Aluminium offers the home handyman a light, strong alternative to wood and other traditional materials. It comes in pre-shaped forms such as angles, channels, tubes and bars, as well as in sheet form.

Sheet may be successfully cut with tin snips, shears and fine-toothed saws, or even heavy scissors will tackle fine sheeting.

When cutting an outside corner, the trick is not to try to turn the comer with the cutting implement. Make the first straight cut slightly longer than required, then make the second cut meet the first. Inside corners are cut simply by making the two cuts meet at the corner point.

An electric jigsaw can be used to cut shapes out of a sheet. Alternatively, score the aluminium sheet repeatedly with a utility knife.

The sheeting may be sawed and drilled as easily as wood. Sawing is much easier when the aluminium is held by a vice. Protect it from jaw

damage with a piece of scrap aluminium or hardboard, and avoid overtightening of the jaws. Saw with light, fast strokes, especially when cutting tubing. Lubricating the saw blade with kerosene or candle wax will eliminate drag. When using a power saw, the feed should be slow and even. This will prevent the saw blade tip heating up and partially welding to the particles of aluminium. Lubricate the blade periodically with kerosene or wax when it is switched off.

Aluminium may be drilled with either hand or power tools, but use metal-working twist drills. Use a centre punch or nail to indent the exact spot (securing the work in a clamp or vice first). Lubricate the drill bit with kerosene or light oil, to prevent overheating. Use a moderate feed pressure and back out the bit occasionally in order to clear loose metal. Aluminium sheet may be bent without any special tools. Draw a line where the bend is re-

quired, then sandwich and clamp the sheet between two straight boards, keeping their edges close to the bend line. The boards should run the whole length of the sheet. Clamp them together with G-clamps, then bend the boards upward while pressing down on the work surface until it is bent to the desired angle. To obtain a sharp, 90degree turn, clamp the aluminium “sandwich” to the edge of the work bench and hammer the crease with a rubber mallet and a block of wood.

To form a curve, use a piece of shaped wood as the inside block of the sandwich. Bend by hand or by hammer, using a rubber mallet or wooden block to protect the surface.

To form corners, in angles of 3mm thickness, mark two 45-degree angles from the point of the bend out to the edge of the material. Mark the centres of two 6mm holes along the angle lines 3mm from the inside flange surface. Drill these holes.

Cut out the notch and bend the material until the joint is closed. The drilled holes give clearance for a tighter bend. Use the same technique to make a comer bend in I.6mm angle, but drill 3mm diameter holes. Aluminium sheet or light-gauge extrusions may be quickly and easily joined by pop rivets. Make sure that only aluminium pop rivets are used and drill minimum allowance holes. These rivets may also be used to join aluminium and wood. Self-tapping screws are another means of fastening aluminium. The screw passes through a clearance hole drilled in the first piece and then cuts its own thread in a smaller hole drilled in the second piece. Tightening the screw pulls the two pieces firmly together. In order to join aluminium sheet and angle for instance, line up the materials and clamp them together. Make a punch mark and drill a small pilot hole through both the sheet and angle. Make the pilot hole about half the diameter of the screw. Separate the materials and enlarge the hole in the top piece (the one next to the screw head). The screw should be able to pass through this hole without binding. Join the pieces together again and drive the screw through the second hole. It will thread into the angle and draw it up tightly against the sheet. For most projects, aluminium requires no surface finishing, other than the smooth finishing of cut edges. It can be bought in pre-anodised colours, however, or clear and colour finishes can be applied to the completed article. It is recommended that any aluminium surface to be exposed to highly corrosive conditions, such as saltwater spray, be protected with a paint coating.