A DIY guide to finishing a live edge timber slab

So, you’ve purchased a beautiful raw timber slab from The Wood Project, but need help to ‘finish’ it?

We’ve put together some how-to tips to help DIYers create beautiful timber effects at home.

How to square end your live edge slab

At The Wood Project we kiln dry our slabs and then supply all of our slabs dressed and flattened to 60 grit through our industrial sander – this means a lot of the hard work has been done for you already.

If you require one live edge and one natural edge for benches, shelves or vanities, you need to measure your live edge slab correctly to achieve only one natural edge and one straight edge. Mark out where you wish to cut, then use a circular saw to cut the edge.

If you are wanting to keep both live edges, there is a method in which you are able to square end your slab, it requires you marking the centre point at both ends of the slab, running a straight edge to each mark, pencil this line in and using square edge you are able to square off the ends, our video shows this in detail.

How to relief cut your live edge slab

If you have a wide slab approximately 600mm wide and above, you will get a lot of tension in the timber, especially with Aussie hardwoods, so its best to relieve the tension which will help with stablising the timber ensuring minimal to no movement or cupping. So what we do is relief cut the underside of the timber slab.

This involves running a saw cut every 50mm increment along the length of the slab, starting 80mm in from the end of your slab and finishing 80mm from the far end (also stay 80mm out from the edges). The cut will go approximately half way through the thickness of the slab ie: 36mm slab, set your blade depth to 17 – 18mm.

How to stabilise your live edge timber slab

What if your slab has end splitting? A lot of slabs do, and we will explain how to stabilse these splits.

Using a 3-4mm drill bit, drill a hole at the end of the split, this will stop if splitting further. Grab a countersink bit, and counter sink your screws diagonally into the timber starting from the narrow end of the split work your way down, alternating sides of the split until you have reached the end. Your slab is now stabilized and you are ready to fill, sand and fine sand your slab!

How to fill, sand & fine sand your live edge slab

After you’ve cut your slab to the correct dimensions, it’s time to prep it ready for coating.

Start sanding with orbital sander. At The Wood Project we use Festool sanders, but there are cheaper orbital sanders on the market that will do the job as well.

Using 60grit sandpaper, select the “grind” option on your orbital sander, which is used for coarse sanding. Tip: Take your time and make sure to get all the sanding lines out from the drum sander.

Once you are satisfied that you have sanded the entire slab well, take the sander off “Grind” function and continue sanding with 60grit sandpaper — again take your time and sand the entire slab well.

After you’ve sanded the top of the slab, repeat the process on the bottom of the slab.

What to do about imperfections

It’s important to scrape out and clear all the surface checks and cracks on the slab, and any imperfections or splitting prior to filling.

Filling the slab

We use Repco Body Filler, a car body filler, mixed with Black Oxide Colour to fill our timber slabs. We find body filler works really well with timber. It’s very easy to use, is cost effective and perfect for slabs with small imperfections; and it holds the black oxide colour well. We use resin for large voids, however that’s a completely different process that requires its own blog!

Once you have added the hardener to your bog, it’s important that you are ready to work quickly, as you only have about 5 minutes before it ‘goes off’. Fill all your voids, and wait 45 minutes for the fill to harden and dry.

How to finish working on your timber slab

Once the ‘bog’ has hardened, it’s time to sand the slab back again. Use the same 60grit sandpaper you used previously, but adjust the sander setting to ‘no grind’.

How to spot fill your timber slab

Look over the timber slab and identify any voids or cracks and watch for areas that are a little low that still require more filling this is called spot filling.

You might notice at this stage that the bog looks a little blue/grey in colour, don’t worry about this, once the slab is coated the bog will come up black.

Preparing your live edge

It’s important to remove any bark you see. Bark left on the edge will naturally want to come off and all the beautiful features of natural timber live under the bark. Plus, you’ll achieve a smooth to touch natural edge.

For natural (live) edges use 60 grit sandpaper and be sure that your sander is not set on “grind”. You want to keep it at fine sanding, and be careful not to go overboard or you’ll sand all the features out of the edge — it’s a purely personal choice of how you want your live edge to look.

Completing your slab for coating

Once we have a perfectly flat and even surface, including live edges and ends, we can change to a 120grit sanding disk to finish the timber off. Arist the edges to take the sharp edges off as a final step and you are now ready to coat.

Coating your timber

When coating a timber slab, you can choose a variety of finishes. We love using Livos’ Clear, a sustainable, plant-based oil, or Evolution Matte Hardwax Oil. We stock both products and are happy to go through the application process with you over the phone, or if you visit us at the workshop.