Sanding: 9 must know techniques for the perfect finish

Man using orbital sander on wooden table
(Image credit: Getty Images)

It may sound simple but sanding a surface the right way is a subtle skill that any DIYer needs to know. Choose the wrong sander, go against the grain, or pick the wrong sandpaper grade and your sanding project could easily go astray. And, add in a lot of extra work for you further down the line.

To make sure that doesn’t happen we have put together a nine point plan that imparts the essential must knows that will help ensure a happy and continued sanding experience. We tell what sander you should use, when you should sand by hand, how to choose and use the right sandpaper grade and why you need to keep your sanding environment as dust free as possible. 

1. Choose the right sander 

When taking on a sanding project you need to make sure that you choose the right sander to get the finish you want. A power sander is the common option for most sanding jobs as they are quick and effective. But which type of sander you choose depends on the project you're working on.

Orbitals sanders are a popular choice thanks to their versatility and ability to leave a smooth mark free finish. They can be used on tough DIY tasks such as stripping paint and getting a silky smooth finish on flat surfaces. Check our guide on how to use an orbital sander for more insight. 

Sheets sanders are similar but are more prone to leaving marks on wood, but this isn’t a big issue if the wood is going to be painted.

For more intricate sanding tasks you need a detail sander (also known as a palm sander) like the BLACK+DECKER Detail Mouse Electric Sander on Amazon. The size of the sander and shape of the sanding pad allows you to get into corners and other hard to reach areas.

For larger and tougher jobs such as sanding floorboards or other rough surfaces where you want rapid removal of wood a belt sander is a good choice.  

Orange detail sander on sanded wooden door

A detail sander is shaped to allow you to get into corners that other sanders don't (Image credit: Getty Images)

2. Sand by hand when needed 

Power sanders are a great choice for most sanding projects but there will be times when you need to go down the sanding wood by hand route to get the best finish. For example, if you have architrave or mouldings around doors or windows, or are painting skirting boards with detail that a power sander can’t reach, then sanding by hand is the only option.

When sanding by hand there are tools that will help make sure you get a good finish. A hand sander like the Stanley Hand Sander from Amazon is a good choice to get a good grip on the surface and help keep it flat and smooth. For more intricate areas sanding sponges are ideal as they mould to the shape of the wood.  

3. Select the right sandpaper grade or grit 

Alongside choosing the right sander and technique, choosing the right sandpaper grade or grit is important to getting the right finish on any sanding project. Sandpaper is split into five different grades – extra fine, fine, medium, coarse and extra coarse. Each grade has a range of grits which are the numbers you will see on the back of sandpaper. 

For rapid removal of paint or wood you need an extra coarse or coarse sandpaper. Typically they will run from 40-60 grit. A 60-100 grit is a good choice for rough bare wood finishes and sanding back previously painted interior doors, door frames and windows with a lot of layers of paint.

The popular choice for most home DIY projects are grits from 120-220. To get rid of minor imperfections and better adhesion on previously painted surfaces 120-180 is a good choice. Try a finer 220 grit where less paint removal is needed, for example between coats. It is also the common choice when sanding painted walls, or rubbing down filler or plaster. 

An array of different grade sandpaper discs

Choosing the right sandpaper grade and using them in the right combination is essential for a smooth scratch free finish   (Image credit: Getty Images)

4. Start low, go high 

To get the best results on a lot of sanding projects such as removing paint from doors you want to start out with a coarse sandpaper. Start with a 40-80 grit to quickly get a smooth-ish and clean surface. Next switch to a 120 grit, followed by a 180 grit sandpaper to get a smooth finish for painting or varnishing.

Using a progression of sandpaper grits helps to remove any scratches from the more aggressive grits. Which can be especially noticeable when applying a clear finish.  

5. Keep your sander flat  

It may sound obvious but when sanding a surface it's important that you keep your sander as flat as possible to ensure that you don’t get unwanted dips and ridges. Try not to spend too long in one area, sand consistently and evenly across the whole surface. 

One tip to help make this happen is to mark the top of the surface lightly with pencil strokes. Once the pencil strokes disappear in one section move on to the next section until all the pencil marks are gone. Repeat the process each time you need to sand the area. 

6. Go with the grain 

Sanding with the natural grain of the wood will help lessen scratches appearing on the surface leading to a smoother and blemish free finish. Going against the grain will push the wood fibres in different directions meaning the surface will not be as smooth or uniform, meaning more work to get the right finish. This is especially noticeable if varnishing or staining wood. Note which way the grain goes and then sand up and down grain.  

7. Stay dust free 

Sanding by hand or with a power sander can create a lot of dust that you can breathe in and will spread itself across every nearby surface. You can wear a dust mask as a safety precaution, but if you have a power sander make sure to add the dust bag it comes with or attach it to a vacuum to stop the spread of dust.

If sanding by hand make sure to clear up the dust periodically with a vacuum and/or cover areas with dust sheets like these ARVO Large Plastic Dust Sheets from Amazon where you don't want dust to settle. 

8. Sand again, and again if needed 

When working on projects that need fine finishing such as painting skirting boards, doors and varnishing you will need to sand in-between coats to get a smooth high quality finish. This is more pertinent when working with bare wood as the grain will raise when the first coat is applied.

Use a 220 grit sandpaper when the first coat is dry and then sand in-between each coat with a 240 grit or higher sandpaper to remove any imperfections or specks of dust or debris that might have settled and dried into the paint or varnish. 

9. Replace your sandpaper regularly 

Sandpaper will eventually get clogged up with dust and debris which will reduce its effectiveness and mean more work for you. Using a dust bag or constantly cleaning away dust will help prolong the life of sandpaper. But once it starts to get clogged - you’ll notice little areas of accumulated dust and debris that weren’t there before - think about changing.  

Steve Jenkins

Steve is Homebuilding & Renovating's DIY content editor, and has been a writer and editor for two decades. He is an avid DIYer with over 20 years of experience in transforming and renovating homes. He specialises in painting and decorating, but has strong all-round building skills, having previously worked in the industry for 10 years.