When I first realized I needed an electric sander my idea was to get an orbital sander. They are easy to use, very safe, cheap, and seem to do a decent work. Don't get me wrong, it's all true. But then, having a budget for only one machine I was wondering would an angle grinder be any good too. Finally I bough both very cheap. I could not know back then I will now use the angle grinder for almost everything and the orbital sander will mostly stay and collect dust.
The angle grinder is an exceptional machine. It's a lot more than a sander: it can sand, grind, polish metal, and most important than all it can cut almost everything. The angle grinder is especially good for cutting metal, sanitary ware, granite tiles, bricks. Just about anything. It's light, affordable and not hard to work with. The only downside is that working with it is a bit dangerous and you should be serious about safety. But more about this below.
Types of Angle Grinders
This is not some kind of scientific categorization, it's just an useful way to think about angle grinders especially if you are choosing your first one. So generally I would separate them by two criteria: by size and by power source. Yeah, one can say they also split on professional, semi-professional and hobby ones, but this is the same for almost all power tools.
By Power Source
- The electric angle grinders are most popular. They have a cable and work with 100v - 220v depending on your network. They come with different power usage - from 500W to several KW. In general the larger is your grinder, the more KW it needs to work well. Avoid those with too little power, they are not good. Even the smallest grinder should be at least 700W. There are ones at 500W but they are usually too weak.
- Battery powered. Of course this is again electricity, but there is no cable. It could be very useful if you have to work in places with no electricity or on a roof, etc. Downsides: they are more expensive, heavier because of the battery, and the power tends to end when you need it most. Still sometimes a battery powered angle grinder is a life savior.
- There are also pneumatic grinders. They are a good alternative to battery powered tools as long as you have a tool to pump them with compressed air.
- And of course you can choose a fuel powered angle grinder - typically for industrial work in the fields etc. These are generally large and professional instruments and will rarely find place in the hobby builder's workshop.
Angle grinders come in several sizes. How to choose the right one for you? Let's see:
- 4.5" / 115mm. This is the smallest possible size for an angle grinder. I like this size a lot because it's light and good for using with one hand. At the same time it's large enough to cut a rebar or elbow which is mostly why I ever need an angle grinder. These are cheap, and the disks for them are cheapest too.
- 5" / 125mm is the most universal size. It's still good for using with one hand, but a bit heavier. However these tend to be of a better quality than the smallest ones, and the slightly larger disks allow you to cut more elements.
- 9" / 230mm. I'll jump directly on the largest size. There are medium sizes - 7" for example - but typically you'll either need a small one or a really big one. The 9" angle grinders are heavy and dangerous and they should always be used with two hands. Think whether you need such one at all - many of hobby builders simply don't.
So, What Can You Do With Them?
Obviously the main purpose of a grinder is to grind and polish stuff. I am using my angle grinders a lot to sand wood boards and beams because we have no access to planned material here. I love doing with with my hand plane but it takes so much more time. So I am using an electric planner for the rough planning and then further polishing the wood with the angle grinder. If I really have time I may also go with an orbital sander at the end.
You can also use it to grind metal. Be careful and don't mix grinding disk with cutting disks. Also, when working with metal always wear protection gear.
However the angle grinder is used a lot more for cutting stuff rather than sanding and grinding. There are disks for cutting metal, ceramic and even wood. Using the grinder is probably the easiest way to cut metal at the home workshop. Be really careful: at the speed of 10,000 - 12,000 rpm these disks rotate really fast and cut everything. Follow all the safety recommendation and don't cut with the angle grinder when you are tired.
So, what are these safety measures we are talking about? Well, most angle grinders have specific safety instructions but here are the most common recommendations:
- Wear protection gloves. Don't rely too much on them: these disks really cut. But still they can save you from light injures especially when sanding.
- Wear protection glasses. I would say do this always, but especially when cutting metal.
- If you are sanding wood or cutting ceramic, wear a breathing mask. These small particles are really nasty and fly everywhere.
- Don't work when too tired, period. If you have a project you absolutely must finish fast, do the angle grinder cutting before other less dangerous tasks.
- Use disks made for your grinder. Follow the instructions of every specific disk and never use tired disks from larger grinder on small ones - they are made for different rotating speeds!
- Never work without the recommended protector on the grinder. Some grinders have different protectors for the different operations. Follow the instructions. This is not a joke.
Other Types of Sanders
While the angle grinder is the first you need to buy, there are some other types of grinders that you may want to add at some point:
The orbital sanders are good for fine-tuning your work, for taking off paint from metal, and so on. They are extremely easy to work with and very safe, but generally slow and not too powerful.
The eccentric sander is like an orbital sander on steroids. It's used with the same purpose but is more powerful workhorse that can be used for parquet flooring for example. Of course, eccentric sanders are more expensive too.
Belt sander are used more often in professional shops and typically but not always they are stationary, fixed on the table. They are used for removing metal, grinding wheels, etc.