Make a Low Cost, Easy Slat Bench with Stylish Design
Using untreated pine lets you make an affordable slat bench that has a stylish design and is very easy to assemble.
Not many are aware of the fact that you can buy untreated pine at Builders Warehouse and that it is far cheaper than PAR pine. We modified the materials and dimensions on this stylish slat bench so that you can make it using untreated 50 x 76mm pine at far less than what it would cost if you used PAR pine. The difference? PAR simply means planed all round and the untreated (although both are untreated) is not planed all round, which means you have to spend a bit more time sanding it. I reckon it's worth spending a bit more time of sanding if you can save so much on the materials!
You will need your drill / driver or combi drill for this project, as well as a circular saw or mitre saw, although you can use a handsaw if you are prepared to put in the effort required.
YOU WILL NEED:
50 x 76mm untreated pine (qty depending on the length you want for your bench)
- Cut for seat slats, legs and crosspieces
6 x 75mm coach screws and washers
Rust-Oleum enamel spray
Drill / Driver or Combi Drill plus assorted bits
Circular saw or mitre saw
Orbital sander plus 180- / 240-grit sanding pads
Angle grinder with flap discs or belt sander plus 120-grit sandpaper
Tape measure and pencil
Couple of workhorses or benches
OPTIONAL: Router and round-over bit
1. If you don't have this done at the store, cut the pine to the length required for the seat. Place the pine on a couple of sawhorses or benches to cut to length.
GOOD TO KNOW: You may not be able to cut entirely through the 50mm, so flip over to repeat the cut on the other side.
2. The bench seat slats are supported by notches in the legs, plus there are also corresponding notches cut out of the two end bench seat slats. The diagrams below show how the legs slot into the ends of the seat slats
3. Cut out the notches in the  legs and  end slats with a circular saw, mitre saw or handsaw. Start by cutting the ends of the marked notches. Set the cutting depth on your circular saw or mitre saw. The notches on the end slats are 150mm in from the end of the slats. Also, keep in mind that the legs and back slat are cut as a mirror image.
4. Use a series of cuts across the areas to be removed, as you can see in the image below.
5. Remove the remaining wood slivers with a hammer.
6. Any wood debris left behind can be removed with a wood chisel. The notches need to be as clean as possible for a snug fit.
7. If you have a router, use a round-over bit to remove all the sharp corners of the seat slats. If you don't own a router, sand these for a slightly rounded edge. This will make for a far more comfortable seat
8. Sand all the pieces before assembly. Because you are working with pine that has not been planed, it might be a good idea to start with an angle grinder and 120-grit flap disc or belt sander. Both of these options will remove a large quantity of surface material fast. After that, you can sand smooth with an orbital sander and 180- / 240-grit sanding pads
9. Place the seat slats face down on a pair of workhorses or workbenches. Allow a 15 to 20mm spacing between the slats. Position the legs in place and add the crosspiece before clamping everything in place. Drill  5mm pilot holes through the leg and into the bench slat.
10. You can skip this step if you don't want to spray the coach or lag screws and washers, but it does add a nice contrast to the finished bench.
11. Now you are ready to finish the assembly by screwing the legs to the end slats as well as the crosspiece that is placed between the legs for support.
12. Now you can apply stain, exterior sealer or oil to finish off the slatted bench.