Our new project for the week is a little different from the commissions I usually get. I got an email from a lady who had seen my work at City Folk’s Farm Store, and wanted me to build her a compost bin. Not just any compost bin, but one that was 12′ long, with three 4′ bins, complete with hatches and latched doors to keep the critters out. I said I could do that (though my own bins are considerably more shabby), and drafted a design.
Dealing with the pressure-treated lumber that this bin is made from had a few considerations in the construction. The joints used in this project are important because they allow for the strongest attachment of the sides, but they will open up over time because pressure treated lumber is extremely wet. As it dries, it will shrink. Also, be aware that there will invariably be variations in the size. Though all of the 2×4’s will nominally be 1.5″ x 3.5″, I experienced a variation of ±1/8″. This can be a problem if you use the nominal size as your standard. Be sure to use superimposition to lay out your joints.
The joints in this particular project are almost entirely half-laps. It’s a lot of fairly tedious cutting, but with a careful work, they will work off the saw, and not require further fitting. It is fastest to use the big ripsaw, but you can use a large tenon saw if you have enough plate under the spine.
Once the half-laps for the frames are cut, they can be assembled, then put aside for the moment. I’m using heavy-duty screws that are approved for use in treated lumber (important!), as well as a waterproof adhesive. This one is almost done, three more to go!