How Can Hand or Garden Tools be De-Rusted?

Remove excess rust with steel (wire) wool soaked in lemon juice or vinegar which are mild acids. Rinse the tools and allow them to dry. You could soak the tools for a period to remove excess rust.
Another alternative which definitely works is phosphoric acid. This is often a constituent of rust removing chemicals and can also be bought in gallon containers from companies which supply cleaning chemicals. It is a powerful acid and can also be used for removing limescale from surfaces. Usually it is diluted with water before use. The objects being cleaned are submerged in the solution and should only be left in the acid for the bare minimum of time to dissolve the rust, otherwise the acid will start to dissolve the underlying metal! I have cleaned an old vice pillar drill vice belonging to my grandfather which developed a thick layer of rust after being exposed to dampness in a shed for over thirty years and the acid completely removed the rust.
Once you remove the rust, rub some oil into them and wipe off any excess. This will help to prevent future corrosion.
Sand can also be used as an abrasive for removing rust from tools.
If you wipe tools with light oil after use, it helps to prevent condensation and subsequent corrosion. Guns and tools were traditionally given (and probably still are) a coating of oil after manufacture and before packing to protect them from dampness and rust.

What Does the Voltage Rating of a Fuse Mean?

Image Courtesy, mtself CC BY SA 3.0 via Wikimedia Commons

The current rating of a fuse specifies the current which the fuse will carry without blowing. Once the current exceeds this value, the fuse will eventually blow. The characteristic of a fuse is such that if the current in a circuit is moderately higher than the fuse rating due to an overload, the fuse will take some time to blow, possibly seconds, minutes or tens of minutes, depending on the magnitude of the overload. If the current is a lot higher e.g. in the case of a short circuit, the fuse will blow in a few tens of milliseconds. While a low voltage or high voltage fuse will blow when the current exceeds the current rating, the current flow in a mains powered circuit can be extremely high (possibly thousands of amps) in a short circuit scenario because the current is coming from a large transformer outside the home. The breaking capacity of a fuse is specified in joules or kiloamps and a mains fuse could have a rating of 10000 amps or more. This is the maximum current the fuse can carry without rupturing. Usually fuses for mains equipment or distribution circuits have a ceramic body to withstand the heat and shock when the fuse blows. The fuse is also filled with quartz sand to absorb the heat and shock and quench the arc when the fuse blows. A glass fuse could simply rupture and possibly cause a fire if it carried such a heavy current. Glass/low voltage fuses may be used on the secondary side of the transformer in the power supply of equipment because the current output of the transformer in a short circuit situation is limited.

Good DIY Gifts For Men?

I better be diplomatic about this and suggest that DIY gifts for men needn't be any different than those which would be suitable for all the ladies amongst us (and even "non-ladies"!) Speaking as a serious male DIYer, I would like a cordless drill with two lithium batteries. The advantage of this battery technology is that the batteries don't lose their charge as quickly, and the drill is always ready for use.
A mitre(miter) saw is useful for making square cuts on timber, dado rail etc. An 8inch version is fine.
Jigsaws are useful for making curved and straight cuts in sheet timber. Go for one with variable speed on the trigger.
Angle grinders are useful for cutting metal and masonry.
A socket wrench set or ratchet wrenches(spanners) are always handy for tightening and undoing nuts and bolts.
Personally I would prefer to buy my own hand tools. While power tools are somewhat similar, the shape and size of hand tools are such that it is better to try them in your hand before buying. I mean how would a woman feel if their partner bought them shoes?

How to Reduce or Prevent Condensation in Your Home

Condensation occurs when air hits a cold surface. Air has a limit to the amount of water it can hold in suspension and the amount of water in the air is known as the relative humidity (measured as a percentage). Once air becomes saturated, the relativity humidity has reached 100%. Now as the temperature becomes lower, air can hold less and less water. Condensation occurs when water laden air hits a cold surface, reducing the temperature of the air. This could be glass in windows, cold tiles or metal surfaces. These surfaces are either colder than other surfaces in a room or are of high thermal conductivity so that heat is sucked out of the air. In any case, the air temperature drops to the extent that it can't hold moisture any more and it is deposited on the surface.
To avoid condensation you have several options. Firstly you can vent moisture laden air (e.g from cooking in the kitchen) so that it doesn't end up in rooms. You can do this by using extractor fans or simply opening windows. Portable gas heaters produce lots of water vapour and should be avoided. Another option is to raise the temperature in the room. This makes surfaces warmer so that moisture doesn't condense out. Double or triple glazing also helps because the external surface of inner panes of glass is not in contact with air outside the house. Removing sources of moisture also helps. This includes house plants and damp clothing. Clothes in the washer should be kept there with the door closed until they are transferred to a drier, or hung outside. Drying clothes in rooms or on radiators transfers water to the air where it inevitably condenses out if windows are closed and the room temperature drops. Yet another way of reducing condensation is to use a dehumidifier. This appliance works by circulating air over chilled coils. This causes moisture to drop out of the air (just like it does on your windows) and collect in a reservoir tank.

How Can a Freezer be Defrosted Quickly?

You can wipe over the ice with a cloth or towel soaked in hot water. This will soften the ice enough so that it can be scraped off. A plastic lifter like the type which is used with non stick frying is useful for getting in under the ice and prying it off. Don't use metal scrapers if the inner surface of your freezer has a foil coating as it can lead to damage. A basin of boiling water placed at the bottom of a chest freezer also helps to accelerate the melting of ice (After having pulled the plug and removing all food)

Why Do Computers Make Noises?

Several things in a computer make noises. First of all, the head in a disk drive makes some noise as it moves in and out over the aluminium platters in the drive during disk access. The head is actuated by devices called stepper motors which can rapidly move the head towards the center or edge of the disk. The motor which drives the platter/platters in a hard disk may also make some noise.
There may be one or more fans in a computer for cooling the electronics. The microprocessor (CPU) is likely to have a fan and there will also be a general purpose fan for drawing air through the machine to cool it. Usually there is a temperature sensor, and the fan cuts in and out as the temperature rises above and falls below threshold levels (just like the way an electric cooling fan for the radiator may turn on when a vehicle with the engine running is stationary for any length of time). Alternatively the speed of the fan may be varied, depending on the amount of processing of data which is taking place. It occasionally happens also on desktop computers when a fan gets old, the bearings can wear and the fan becomes noisy.
The power supply may also make some noise. When a current passes through electronic components, sometimes, electric or magnetic fields can cause movement (e,g, if you hold an older style, non switched mode, power adapter up to your ear, you can hear it humming). A sudden demand for power from the supply could cause clicking sounds.
Other clicking sounds can be caused by thermal expansion/contraction as the computer warms/cools (like the way gutters or roofs can creak when the sun comes out).
The old style dial up modem sounds were due to the "tones" which were sent down the line. Digital bits can't be sent directly down a phone line. Instead, various tones or sound frequencies were used to represent "ones" and "zeros".
As regards cooling fans, there is no harm installing a utility on your computer which displays the core temperature of the CPU or (CPUs if the machine is dual core or quad core). I have a utility called core temp installed which displays the temperature on the taskbar. It will power down the machine or display a warning if the temperature exceeds a set value. If you have a laptop, leaving it on a sofa can cause it to overheat, because the air intake may be under the machine and can get blocked. Another tip is to setup a laptop running on battery power so that it goes to sleep after a few minutes of inactivity.

What is a Neon Glow or "Phase" Tester?

A neon glow tester, sometimes called a "phase" tester is a device used to detect mains voltages. The neon capsule in the device is usually sensitive to voltages from 90 volts upwards. Contact must be made with a live terminal for the neon bulb to glow. When doing electrical maintenance work, a neon tester can be used to double check power is turned off after switching off a breaker. Neon testers are commonly available in the form of a flat screwdriver whose blade is sized to suit the screws in electrical fittings.
Newer type hand held electrical testers such as the Fluke VoltAlert use an electronic detection circuit which activates an LED when the tip of the tester is in close proximity to a live terminal or power cable, actual contact is not necessary. These testers are useful for detecting presence of voltage e.g in a power flex or on the output of a breaker. However if the tip is too far away, the LED may not light up, giving the false impression that a circuit is not live. So they should never be used to test for absence of voltage. A neon tester should be used for absolute certainty when testing (and the tester should be pre-checked by touching it against a live terminal , e.g. the outlet of a socket to ensure it is working properly).

How Can a Pinhole Leak be Temporarily Fixed Until a More Permanent Repair Can be Done?

Ordinary 2-part epoxy resin also works well for sealing leaks. I have used it successfully for repairing a long crack in the polystyrene spray nozzle of a hose. Make sure you get the quick setting stuff which hardens in about 10 minutes. Try and dry the joint thoroughly, and if possible, rub it with sandpaper to improve adhesion. Let the epoxy stiffen slightly before applying to prevent it spreading out. Heat from a hair drier accelerates the curing process. As far as I know special pipe sealants are epoxy based.
Another alternative (although this is theoretical and I haven't tried it!) is to use a hose clip. Keep one opened out and if you have a leak, wrap it around the pipe, push the end of the clip back into itself and semi-tighten it with a screwdriver. Push a small piece of rubber (bicycle patch, piece of old tire, rubber boot or whatever) under the clip over the hole and tighten. The advantage of this is that the water wouldn't have to be turned off and the area around the hole wouldn't need to be dry but it would probably only work on a hole in the actual pipe itself where the clip would exert sufficient pressure on the patch. You can also buy emergency clamp type fittings which seal over a hole, effecting a temporary repair until the section of pipe can be replaced.
Yet another repair method for cracked brass fittings is to solder them. I had to do this when a fitting on a heating system in my workshop developed a hairline crack during a lengthy period of snow during the winter. (Haven't looked at it for years so hopefully it's still water tight!).
It's wise to know the location of all your stop cocks/gate valves, and write the function of the valve on the wall behind it with a marker, or tie a label around it. In an emergency, you don't want to have to figure out which valve shuts off which pipe. Also valves tend to stick and seize up after years of disuse, so "exercise" them at least once a year by screwing off and back on again. It's actually a good a wise idea to add a redundant valve in case your main water shut-off valve fails. Another option is to fit a quadrant ball valve in addition to the main valve which can be quickly turned off by turning it through 90 degrees (These are the ones commonly encountered on gas and air compressor lines or on oil tanks). Quadrant valves don't normally seize up.

Can an Oil Stain be Washed Out of a Cotton Shirt?

Any of the well known hand cleansers used by auto mechanics or similar are excellent for cleaning oil stains from clothes or even worse carpets. The stuff I use on my hands after I do work on my lawn mower is excellent and seems to remove even the worst grime. Some of these cleansers contain hydrocarbon solvents which may remove colour from clothing, so try using some on the tail of the shirt first to see what the affect will be. Wash the shirt in your washer after removing the majority of the stain. Cotton is a somewhat porous fabric compared to to synthetic fibres which are more smooth. So the oil content of the stain will be removed, however you may not be able to remove all the stain, especially if black, waste oil is involved.  However it may become less obvious after further washes.

How Can I Mould Stepping Stones For the Garden Using Cake Tins?

If the pans are slightly tapered from top to bottom, there shouldn't be any problem releasing the cement, just as it is easy to release a cake from a mould or a sandcastle from a bucket. Cement doesn't normally stick readily to smooth metal. You could spray the inside with silicone lubricating spray and this should help also or even rub around the inside of the mould with some butter, Vaseline or similar. You only need to rub the surface in the same way that pans and dishes are coated when cooking or baking.
When the cement is set hard after a few days, lightly tap all around the base and sides, turn upside down and then if possible, hit the edge of the pan off the edge of a surface such as a bench, wheel barrow or kerb. This usually works when releasing plants from pots so it should work with cement also.
Leave the cement for about a week before walking on it so that it attains its full strength.
If you want to make the stones really strong, you can reinforce them by laying any scrap metal items you want to dispose of inside the cement. Half fill the mould with cement and then place the pieces of metal flat on the cement. Fill up to the top of the mould with cement.
If the stones are going to be walked on, they need to be at least 2 to 3 inches thick.