Hammer drills are very versatile tools, not just for professionals. The basic hammer drill has a switch which disables the hammering action, turning it into a normal drill. Many hammer drills can also be used as screwdrivers as well. You also have much more powerful hammer drills, the rotary hammer. It is the right tool for drilling in really hard materials, such as concrete. Here is a short hammer drill overview.

For most DIY tasks the standard hammer drill is the best choice. The hammering action makes it possible to drill in hard materials. And you can disable the hammering action when you don’t need it. The hammering action generally damages softer materials. So if you are going to drill a hole in a concrete wall which is covered by a layer of plaster, you need to be careful. The hammering action will damage the plaster. The solution is to drill without the hammering action until you reach the concrete behind the plaster, then you enable the hammering action.

In most cases, a cordless drill is more convenient than a corded drill. But if you are going to use the hammering action a lot, you may prefer a corded hammer drill. The hammering action quickly drains the battery.

Of course, you also need drill bits that are meant for masonry drilling. Standard drill bits will quickly break if you use them in hard materials. But note that the rotary hammer uses its own special bits.

If you are going to do a lot of drilling in hard materials, you may prefer to use the more powerful rotary hammer rather than a normal hammer drill. It has a piston mechanism that does the hammering action. This makes the hammering action of the rotary hammer much more powerful, letting you drill holes much faster. But you can’t use drill bits meant for hammer drill. The powerful action of a rotary hammer requires special bits that lock tighter into the hammer. Ordinary bits are too smooth, they will be pounded loose very quickly.

Rotary hammers are too big and clumsy to be used in soft materials. But you can disable the rotary action and turn the rotary hammer into small destruction hammer, which can be used for chipping jobs.

The combination hammer is a combination of rotary hammer and demolition hammer. You can use them both for drilling concrete as well as for chiseling and chipping. Of course, they are not as powerful as standard demolition hammers but you get good value for your money. Demolition hammers are similar to rotary hammers but they lack the rotary action needed for drilling. It is the tool for demolishing concrete and masonry.

Note that hammer drills often have three modes, rotary, hammer and rotary+hammer. Rotary mode means standard drilling, without the hammering action. Hammer mode means that the drill does not turn, it just hammers, this is useful for chipping. The rotary+hammer mode is used when drilling in hard materials. The basic models seldom have the hammer only mode.

Painting is time-consuming but relatively straight-forward, as long as you have the right tools and have done the right preparations. Here is a short DIY painting overview.

Painting is generally easy and it can even be a little bit of fun. But preparing the surface is a time-consuming and tedious task. Unfortunately, the quality of your paint work will depend on your preparations. No matter how skillful painter you are, poor preparations mean poor results. On the other hand, if you do the preparations right and have the right tools, you are likely to get good results.

What tools you need depend on what you are painting. If you are working on or near the ceiling, a stepladder is the best solution. Chairs are not a good solution. But even a simple stepladder requires some safety precautions. First, make sure that you have a sturdy ladder. Don’t step on the on the top rung of the ladder, it is meant for hands not for feet. Never lean out to the side, trying to paint some spot that is just within reach. Instead move the ladder to the spot.

A breathing mask is not necessary but it prevents dust and fumes from reaching your lungs. Goggles are seldom needed for painting but can be useful when preparing the surface for the paint. If you are painting the ceiling, use a painter’s cap to protect your hair and head. Needless to say, you also need some old clothes and shoes. Wet paint is easy to remove from clothes but once it has dried it is much tougher to remove. Put on old clothes so you don’t need to go and remove paint all the time.

Before you can start painting, you need a clean and smooth surface. How you achieve this depends on what kind of material you are going to paint. For wooden surfaces a sander is the best solution. A pressure washer is a good way of cleaning concrete and masonry. Be careful with other materials, a pressure washer can damage softer materials. Caulk is generally the best way of getting rid of cracks.

Paints are divided into exterior and interior paints. Obviously, exterior paints are made to withstand weather while interior paint is supposed to be used only indoors. You can use exterior paint indoors but most of them are not designed to withstand scrubbing. The same goes for stains, you have indoor and outdoor stains. Note that stains can be used also on concrete, not just on wood. Before you start painting you also need to mask the areas you are not going to paint.

Estimating how much paint you need is easy but you need to make sure that you have enough with paint. A rough surface requires more paint than top-coated surface. Having some leftover paint is a good idea, you probably need to touch up parts of the surface later on.

You have four different ways of applying the paint, you can use a
– paint sprayer
– brush
– roller
– pad

Rollers are best for large flat areas, great for walls and ceilings. Brushes are generally used for smaller areas. Pads don’t leave any brush marks but they are more difficult to use than brushes. If you have never used pads, stick to brushes. If you use pads, you have to dip them in paint more often than rollers and brushes.

Once you have completed the painting, you have another boring task left, cleaning up. The best solvent for water-based paints is warm soapy water. For other paints, use paint thinner. Getting dry oil-based paints off your skin is difficult so try to remove it as soon as possible.

Drilling often requires that you also use the right screw anchors. This often works out fine even if you don’t really know what you are doing but sometimes things can go badly wrong. Here is a short screw anchor overview, helping you to avoid the worst mistakes.

Every now and then you need to fix some item to a wall at home. Generally, this is very straight forward, you drill the necessary holes, insert the plastic plug, also known as a screw anchor or wall plug, and secure the item to the wall. But like most things, quite a lot of things can go wrong. Unfortunately, house walls are built from many different materials so it is impossible to use the same process for all walls.

Before you start drilling into any wall, make sure that no wires or pipes are hidden under the surface. Fortunately, you can buy inexpensive gadgets, called stud detectors, which check for pipes and wires in walls. Once you have located suitable locations for the holes, you need to determine how deep you need to drill. This depends on what screws you are going to use. What screws you need depends on what you are going to fix to the wall. In most cases, you can’t just secure the screw into the wall, you need a fixture to make sure that the screw is held in place.

The most common fixing is the plastic or fiber expansion plug. They are cheap and last forever. In most cases, extension plugs come with instructions on the package or the plastic strip holding the plugs together, telling you what drill bit and screws to use. Some plastic plugs are color coded, you should use a 5 mm drill bit for yellow plugs, 6 mm for red plugs,7 or 8 mm for brown plugs and 10 mm for blue. The screw size is not clearly defined but generally you use screw size 6-8 with yellow plugs, 8-10 with red, 10-14 with brown and 14-18 with blue. But always check the instructions that come with the plug, plugs come in a wide variety of sizes, shapes and colors.

Obviously, the hole has to be deep enough to hold the fixing and the screw. Once you done with the drilling, make sure to remove the dust out of the hole. Otherwise, the plug will not hold very well. Use hammer to get the plug flush with the surface. Note that the hole should fit the screw, not the wall plug. You want the screw to go all the way through the plastic wall plug and split it open to force the tightest fit possible with the wall.

Note that if the wall has plaster, you should make the hole deep enough so that plug can be pushed through the plaster, into the masonry. Otherwise the plaster may crack when you tighten the screw. It also best not to use the hammering action before you hit the masonry behind the plaster, the hammering action is likely to damage the plaster.

The screw anchor is not the only type of fixing available but they are easy to use and very inexpensive.

Rechargeable nickel-cadmium, also called Ni-Cd or NiCad, batteries have been around for a long time. They are cheap, something that has made them very popular to use in low-end consumer products. But Ni-Cd batteries have a number of shortcomings compared with newer types of rechargeable batteries.

The first nickel-cadmium battery was developed in Sweden back in 1899. The early Ni-Cd batteries had higher energy density than lead-acid batteries but they were much more expensive. The robustness of Ni-Cd batteries made them very popular. A lot of improvements have been done and Ni-Cd batteries were for a long time the best type of rechargeable batteries. They have also become much cheaper. But nowadays, the newer nickel–metal hydride and lithium-ion batteries are in most ways better than Ni-Cd batteries.

Ni-Cd batteries are often used instead of standard primary (non-rechargeable) batteries. Since they can be recharged more than thousand times, it quickly becomes much cheaper to use Ni-Cd batteries instead of buying new primary batteries. A lot of devices, such as digital cameras and cordless power tools, use special Ni-Cd batteries.

One slight problem with Ni-Cd batteries is that the cells have a voltage of 1.2 Volt. This is significantly lower than the usual 1.5 Volt. Most devices, but there are exceptions, have no problem with the lower voltage. In fact, the voltage of primary batteries decreases during discharge, often they go well below 1.2 V per cell. Ni-Cd cells on the other hand stay close the initial 1.2 Volt during discharge.

Nowadays, Ni-Cd batteries have trouble competing with the newer nickel–metal hydride and lithium-ion batteries. One reason is that cadmium is an environmental hazard and a lot of governments have restricted the use of Ni-Cd batteries. This includes the EU which has banned the use of Ni-Cd batteries in consumer products. In the US, a disposal fee has been imposed, making the batteries more expensive. But Ni-Cd batteries have a number of technical shortcomings as well.

Overcharging is less of an issue than with many other rechargeable batteries but if the battery is overcharged the battery could emit oxygen gas. In order to avoid rupture, the batteries have vents so excess gas can escape. This safety mechanism adds to the production cost.

In batteries made up of several cells, cell reversal is a potential problem. If one cell is completely discharged before the other cells in the battery, the cell could be reversed charged which damages the cell and could generate hydrogen gas which is highly explosive.

A very annoying problem with Ni-Cd batteries is the so called memory effect. If the battery is recharged before it is completely discharged, it may remember this point as when it is completely discharged. This means that the capacity of the battery is reduced. Repeated overcharging can also cause problems, some batteries start to discharge very quickly.

Despite the shortcomings, Ni-Cd batteries are used a lot, especially in the US. In EU on the other hand, they are banned, so you won’t find any Ni-Cd batteries.

Nickel-metal hydride batteries, often called NiMH or Ni-MH, are one of the main types of rechargeable batteries. But lately they have had trouble competing with the cheaper Ni-Cad batteries and the superior Lithium-ion batteries. Here is a short nickel-metal hydride battery overview.

Most of the early development of nickel-metal hydride batteries was done in Europe, mainly in Germany and Switzerland. It would take quite some time before NiMH batteries were commercially viable. A lot of technical problems had to be solved before NiMH batteries were good enough for consumer products. The first NiMH batteries were introduced in 1989.

Compared with the older nickel-cadmium (NiCad) batteries, NiMH batteries have a number of advantages. One of the main reasons for replacing NiCad batteries with NiMH is that they are more environmentally friendly. Cadmium is an environmental hazard. NIMH batteries also have a higher energy density than many other type of batteries. One exception is lithium-ion batteries which have significantly higher energy density.

But NiMH batteries also have a number of shortcomings. Like NiCad batteries they suffer from the so-called memory effect. The batteries lose capacity after being repeatedly recharged before being completely discharged. Lithium-ion batteries have no memory effect. Due to the memory effect, many recommend that you run down NiMH batteries completely at least once a month.

Charging NiMH batteries can cause a number of issues. A complete discharge can in worst case cause irreversible damage to the battery. Some, but far from all, devices using NiMH batteries can detect when the voltage is reaching dangerous levels and shut down.

Overcharging can damage the battery so many chargers either have a fuse or use trickle charging to prevent overcharging. Trickle charging means that a very low current is used. In any case, it is highly recommended that you don’t leave the battery in the charger once it has been fully charged.

NIMH batteries have higher self-discharge than most other types of rechargeable batteries. Self-discharge is not a problem with primary batteries, that is batteries which can’t be recharged, but rechargeable batteries suffer from significant self-discharge. The term refers to the fact that the batteries lose capacity when not used. NiMH batteries can lose as much 30% of their capacity per month. This makes the batteries unsuitable for clocks and other devices that use little electricity but are supposed to run for a long time. New NiMH batteries with lower self-discharge but also lower capacity have been introduced.

NiMH batteries have been replaced in many high-end devices by the superior but more expensive lithium-ion batteries. Outside EU, the cheaper NiCad batteries are often used in low-end devices. But in EU, NiCad batteries have been replaced by NiMH batteries in most consumer devices due to the Battery Directive which banned NiCad batteries in the EU. NiMH batteries are also used in some electric cars.

Most likely you have some products that are using lithium-ion batteries, nowadays they are used in a lot of different devices, such as cell phones, laptops and power tools. Also electric cars are using lithium-ion batteries, obviously they need much larger batteries than smaller devices. This is one reason why some people are worried that the supply of lithium will not be able to meet the demand once electric cars become popular.

The rechargeable lithium-ion batteries have a number of advantages compared with other types of rechargeable batteries. They have high energy density meaning that they can be made powerful but still lightweight, a very useful combination for portable devices. Compared with earlier types of rechargeable batteries, lithium-ion batteries have no memory effect and slow loss of charge when idle. Lithium-ion batteries can be charged more than thousand times. Unlike many other rechargeable battery types, lithium-ion batteries contain no toxic metals.

Rechargeable lithium-ion batteries are not a new invention, the first working model was developed in 1979. A very important breakthrough came 1985, by using lithium cobalt oxide rather than metallic lithium, most safety concerns were solved. The first commercial lithium-ion battery was released in 1991. In the early days, the batteries were expensive but thanks to technological progress, the batteries have improved while prices have dropped. But lithium-ion batteries are still expensive compared to most other rechargeable batteries.

Safety has been an issue for a long time. Hot batteries can in worst case explode. Overcharging a battery can make it hot, which could cause it to explode or catch fire. Only a few batteries have caught fire but the risk is real, although extremely low. Dell recalled over four million batteries after an incident with a burning laptop. After that a potential problem was found in batteries manufactured by Sony, more than nine million batteries have been recalled. One reason why lithium-ion batteries are more expensive than other types of rechargeable batteries is due to the fact that the safety measures required for lithium-ion batteries are more expensive than for other types of rechargeable batteries.

By recycling lithium-Ion batteries, the supply of lithium can be boosted. In 2007, batteries made up 25% of the total use of lithium, and the share is growing. This growing demand for lithium can cause trouble in the future but recycling of batteries has been suggested as the solution. Recycled batteries could supply much of the lithium needed for new batteries in the future. This is especially important if, or when, electric cars become popular. But so far only one company, Unicore of Belgium, has a process for recycling lithium-ion batteries. In other words, it is still far to go before a working recycling infrastructure is in place. One problem is that recycling lithium-Ion batteries is much more complicated, and expensive, than recycling standard lead-acid batteries.

Drilling wood is fairly straightforward but harder material such as concrete is a completely different story. First you need to have the right tools, a hammer drill and special drill bits for masonry drilling. But even with the right equipment you still need to know what you are doing. Here are some basic drilling guidelines for concrete.

Drilling into hard materials, such as masonry and concrete, requires special tools. It is not absolutely necessary to use a hammer drill but a hammer drill is highly recommended. Drilling in hard materials is tough work, a drill with hammering action will do most of the hard work for you. A standard drill on the other hand has to work very hard and you may overheat the motor of the drill. That said, also cheap hammer drills may have trouble with concrete.

Note that if you are going to drill large holes, larger than half an inch in diameter, into concrete, a hammer drill may not be good enough. You need a rotary hammer instead. Rotary hammers are fairly expensive so you may prefer to rent rather than buying a rotary hammer. Of course, the rotary hammer can also be used to drill small holes in hard materials as well. Some rotary hammers also have a chipping function.

You need good drill bits for concrete. Standard twist bits, made of HSS steel, are seldom good enough. Special masonry bits are much better. Typically they have a tip made of tungsten carbide or durium while the body is made of steel.

Concrete drilling must be done slowly. Fortunately, the hammering action will help you so you don’t need to push hard against the drill. You need to withdraw the bit from the hole once in a while to remove the concrete dust. Since the drilling will take some time, make sure that your position is comfortable. If you hold the drill too high, you may not be able to hold on to the drill. The hammering action also makes it tougher to handle a hammer drill than a normal drill. It is much easier to drill into mortar than concrete, so if you can choose drill the hole in mortar rather than concrete.

Note that you should use safety goggles when drilling in concrete. It will be dusty so a vacuum cleaner can be handy afterwards. If you are doing a lot of concrete drilling you may want to use a dust mask. Beware that the drill bit will get very hot so don’t touch it for a while after the drilling is finished. If you want to change bits, wear gloves.