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Prepping woodwork is a basic yet extremely valuable – and often tricky – skill that many of us have yet to master.

 
Luckily, there are so many techniques and tools out there to help you on your journey to becoming a fine woodworker. All you need are the essentials: varnish/primer, sandpaper/sanding pads, a dusting brush, a paintbrush, some sugar soap, a cloth, warm water, and a good old sander tool.
 
In this blog, we’re going to help you figure out the best methods to prep wood for one of the most common reasons: painting. This can mean anything from prepping doors, window frames, and window sills, to getting fresh woodwork ready for a lick of paint.
 
Read along to learn more about the process, and hopefully become a pro!

 

Getting Started

Now that you're ready to go, we'll go through the prepping process.

The typical way to prepare wood for painting is by sanding. This removes old paint and makes the surface even so that there are no imperfections, making it easier for the fresh paint to bind to it, giving you a nice, smooth coat. 

 

Sanding is done by most amateur decorators by using sandpaper and folding it down to rub against surfaces, however, there are many other more effective ways to sand if you want a professional finish.

 

Using an orbital or belt sander, or even a multi-tool can greatly improve your sanding quality. This is because they use powerful motors (to decrease fatigue and improve precision) and filtrated dust collection bags (to keep the dust at bay) which a single piece of sandpaper and a bit of elbow grease simply cannot compete with.

 

But enough about sanding for a minute. First, any holes, cracks, and scratches must be removed. Let's go through the process together:

  1. A generous amount of wood filler needs to be applied to problem areas - especially deep holes. This can be done by getting a flexible scraper to apply over your woodwork.
  2. Once dry, a stiffer scraper needs to be used to scrape off the excess filler. This does not need to be perfectly smooth as the sandpaper will take it down later.
  3. More filler then needs to be added to deeper holes. This will give you a much smoother finish. Continue around the woodwork in the same way until all holes look filled.

Sanding

Now, it's time to sand. You should start with either a sanding block or folded sandpaper to get used to sanding. Here are some tips to help you hone your skills:

  • Always go with the grain of the wood when sanding. This will give you the best possible result with fewer marks.
  • Use the right sandpaper. Use coarse sandpaper to take the first layer of filler off, then use finer sandpaper before going to a medium grade.
  • Remember the nooks and crannies. There can be a lot of areas coarse sandpaper can't get around, so get to the hard-to-reach areas using finer sandpaper.
  • Treat your knots. If there are any distinctive knots, treat this with a knotting solution. This is particularly apparent when painting fresh woodwork.
  • Avoid corners. You don't want to dent your corners, so keep the sandpaper as flat as possible and try not to tip it.
  • Avoid over-sanding. The worst thing you can do is scrub the wood so hard, you create dints. This will make the surface uneven, making for a bumpy paint job. Not a good look.

Varnishing

Once you've finished sanding, you'll need to clean up the debris and apply a coat of varnish or primer. This allows a good key for the other coats to follow. Here's how:

  1. Ensure woodwork is free from dust. This can be done by using a dusting brush.
  2. Make sure there are no greasy marks.  Do this by applying a generous amount of sugar soap onto the wood. Use a decorator sponge to wash it down, and a cloth soaked in warm water to rinse. You'll get it clean and sparkling!
  3. Apply primer with a paintbrush. A good 2 in 1 undercoat & primer is perfect for this. Use smooth, long strokes to get the best coverage. Alternatively, you can apply varnish in the same way. This forms a firm foundation for the paint.

Using Power Tools

Now that you understand the basics of sanding and varnishing, you can get familiar with power tools. 

Firstly, we'd advise you to get your essentials together, remove the holes, cracks and scratches and work out a sanding progression so that you use the right sandpaper at every stage of the sanding process.

The typical sanding progression list looks like this:

 

220 grit, 180 grit, 150 grit, 120 grit, 100 grit, 80 grit.

 

It is important to note that the lower the grit, the more aggressive the sandpaper removes the material, which means you'll be left with deeper scratches. E.g. 80 grit will be the most aggressive.

In contrast, the higher the grit, the less material will be removed, and the shallower the scratches. This means 220 grit with be the calmest on your surface.

UK Planet Tools recommend starting lower and working your way up, but you'll soon figure out the best grit progression the more you do it. You'll probably only use around 3 levels of grit in total.

The Orbital Sander

The first power tool to try is the Orbital Sander.

These sanders take abrasive sheets and move in a - you guessed it - orbital way, which is deemed gentler than other types of sander tools, such as the belt sander (but we'll get to that later). They can be used for varying work areas, particularly smaller spaces, as they also come in half sheet versions, third sheet versions, and quarter sheet versions.

With the right abrasive, these tools are best for giving you a finer finish, due to the lack of aggression when using the tool.

Now, we know, we know. You want to try this baby out for yourself.

Here's a little how-to guide:

  1. Ensure holes are punched into your sandpaper. This allows the dust collection system to draw sawdust up.
  2. Attach the sandpaper sheet to the pad. Do this by wrapping it round as tightly as you can before holding it down with metal clamps. 
  3. Begin to sand in the direction of the grain. Going against the grain will result in dips.
  4. Start from the left and work your way to the right. This is a handy trick to sand evenly.

 

The Random Orbital Sander

Now that you've tried out the orbital sander, you should give the random orbital sander a try.

What's the difference, you ask? Just take a look for yourself. The design is very different, and the tool itself moves in a better way. 

How? Well, this tool features a pad that has a round sanding disc attached to it, rather than sandpaper, which already has holes in it to reduce the amount of dust, lining up perfectly with the dust collection bag. This means less mess, no punching holes, and fewer toxins to breathe in.

It works by vibrating in tiny circles to allow you to sand in random directions, moving in a spinning motion, as well as in an orbital manner. This eliminates common sanding mistakes such as cross-grain scratches and swirl marks. Although it is harder to control, we'd say the sander removes wood much faster than the orbital sander and gives you a professional finish.

Overall, it is more forgiving than a common orbital sander and works for most sanding applications, making it a great beginner tool.

Here's how to use it:

  1. Attach the round sanding disc to the pad. This can be attached with either a pressure-sensitive adhesive or a hook and loop. This may seem velcro-like. 
  2. Move the sander in an orbital motion and spin. This will give the sander the ability to remove a lot of material quickly.
  3. If you are sanding a lot, attach a vac system for sawdust evacuation. The collection bags are great for a small amount of sanding only; you may find they fill up fast.
  4. Don't tip. Like always, keep the tool flat and avoid rounding edges. You don't want your masterpiece ruined by dips.

 

The Belt Sander

Now, the belt sander is quite different from the orbital sanders.

It is quite aggressive, so it is best to use on large, flat surfaces in a short period. It is prone to leaving markings due to how rough it is - especially when in the wrong hands - so do make sure to go over it with your orbital sander to clean up the mess.

Sounds off-putting, right? Maybe. But maybe not. Let us explain why. While this tool is aggressive in nature, it is actually the best tool to use. It works at a high speed, meaning you'll get the job done a lot quicker if you start off with this tool. It is particularly efficient for trained woodworkers who may need to work to a deadline.

How does it work, you ask? To put it in simple terms, it uses a mechanism that revolves a belt abrasive, allowing you to sand a particular spot at speed. It is high-performance, usually with a powerful motor and variable speed dial to adjust the speed.

Here's your guide to using the belt sander:

  1. Insert your sandpaper. You can do this by flipping the tool over (switched off) and releasing the tension lever to take the tension out of the front rotating drum. It should just slide in. Make sure the arrows are pointed in the direction of the spin before putting the tension back on.
  2. Turn the sander on to see if the belt rubs or slips. This is important to avoid accidents. If you find it does slip, adjust the tracking knob to keep the belt centered.
  3. Move in line with the grain. This keeps it moving at an even, smooth pace (but you know this by now). Do not press down on the sander, it will do the work. Move in a zig-zag motion and don't tilt for the best result. 
  4. Dial the speed down. As aforementioned, most belt sanders come with variable speed dials. Use a lower speed for delicate work. 

 

The Multi-Tool

If you want a tool that's good for sanding edges, corners, and intricate areas, a multi-tool may be the way to go.

This tool is great for sanding as you can replace the sanding heads with different sizes for the best result, depending on how large the surface is.

  • For a large area, it is best to go with the round sanding pad, just like you did with the random orbital sander.
  • For edges, a delta triangular-shaped sanding head is your best bet, as its own edges will allow you to glide over the contours of the wood.
  • For other tricky areas, a profile sanding head may be efficient, as you can use different shaped blocks to completely change the profile of your sanding head.

The downside to the multi-tool, however, is that you may need to invest in expensive tool blades, as cheaper ones may not last longer than one sanding session. Despite this, though, it is still worth your while if you've already got a multi-tool handy.

Here's your how-to for sanding with a multi-tool:

  1. Use dust extraction where possible. This may not always be easy with a multi-tool, but doing so will keep the area tidy with less debris.
  2. Attach the sanding pad of your choice. Choose from the options as shown above. You can even use the same pads you used for the orbital sander if it uses a 'Hook & Loop' fastening system and is still in good condition.
  3. Turn your variable speed dial down. The multi-tool will run a bit too fast on full speed as a sander, so it is important to turn it down to around the 2-3 mark.
  4. Run the sander head over the wood. As always, go with the grain. 

 

Over to You

Now that you understand how to sand, use your sugar soap to clean off the debris, then varnish the surface. Once it has dried, you can go ahead and start painting.

Remember: in your journey to becoming a prepping pro, you'll learn more through trial and error, so don't be afraid to mess up now and then. While you won't become a master sander overnight, you will with some perseverance (and of course, a hot cup of coffee to keep you concentrated).

Best of luck!