This week's metal project was wood! We need [want] a planter to grow some veg in once the weather picks up. (It was blooming freezing this weekend.)
"Octagonal" was the design spec, so that it mirrored an octagonal paved inset to a gravel area. After looking up a few measurements and ratios and stuff and translating that into numbers of planks to buy, I was off!
I popped down to George Walker's, our local friendly timber yard and picked up some rough sawn Larch decking timber.
Apparently in the US, this rough sawn timber is what is almost always used for decking - not the planed, grooved and treated softwood planks we get in the UK (and Europe?). Who knew! George Walkers team, that's who!
Generally, George Walker use Tanalith E to treat wood, which they say is safe for vegetable growing. The Larch is untreated anyway, so I didn't have to worry about chemical bleed at all.
The internal angle for octagonal beds needs to be 135 degrees. [Note for Pedants Corner: Well, it does for regular octagons.] At one point I was reckoning on cutting both 'ends' of each side, to make a nice even joint but that would require a lot of accurate cutting. As this was my first outing at making something like this, I figured out that I could keep construction easier by leaving one end square cut at 90 degrees and then cut the abutting end at 45 degrees; making a sum of 135 degrees - ta da! You get a small 'step' on each corner as the 45 degree cut side is longer than the 90 degree cut side. At least that's what Mr Hypotenuse told me. So, after a bit setting up of my Hitachi circular saw I got cutting. (I know, shameless product placement, but you never know who's reading and I could do with a Chop Saw.)
I used a workbench that allowed clamping each soon-to-be-half of the plank to prevent it falling away and splitting whilst still being cut, yet at the same time allowing plenty of clearance for the circular saw below and at the end of the cut. To the untrained eye, it might look like a garden chair. If that's what you're thinking then please reread the first half of this paragraph.
After a couple of cuts I was quite pleased with the results - the cut was true to the markings I made on the wood. (I guess in hindsight I should have done some test cutting first and then I could have gone with the 'equal angle cut on both ends' approach. Lesson learned.) Anyhow, having got effective, at this point I got a bit more efficient and stopped making so many pencil marks on the wood - trusting instead that with the right positioning mark for the saw - all wood be well (wood! ha ha, do you see what I did there). It was. Move on.
Having made all the cuts, I then began assembly. After wrestling with the first couple of joints, I had a bit of a "Duh!" moment and decided I should make a tool to help with the job. I cut a bit of angle iron up ... "How? you ask - well, with my trusty De Walt angle grinder - again, an even more handy tool [and another product placement]. I then welded bolts to the central section to create a three part 'jig' (?) upon which I then could set the angle I needed and, having positioned, could then hold the wood section (side) for each joint. After a bit of struggling, I then learned how to use the tool I'd made; which was to set it against the angled-cut-end and use that to position the 90 degree end. In this way, the jig helped a lot, and in no time, I was rattling through the joints.
Soon, assembly was finished. I'm reasonably pleased with the result - the bit I was most worried about - getting a regular octagon, twice so that the two-storey construction works...well, worked!
There is a step in each joint, as I said at the start, and I'm not sure I've finished with the joining yet - I screwed in from each end of each joint - so four screws per corner. The whole thing still feels a little wobbly. That's not the end of the world at it only has to hold soil in - the soil will keep the walls in place. I'm considering putting some corrugated nails into each corner too, just to help.
The base is open too - I'm going to line the planter with landscaping fabric - it should let water out and keep the soil in.
Overall, pleased. A good days work.
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