Materials:
1 45-gallon 'food grade' drum, nothing that held TOXIC chemicals!
4 40" x 2 x 4" (frame uprights)
2 29 3/4" x 2 x 4" (frame horizontals)
2* 40 5/8" x 1 x 3" (cross braces) white pine
4 23 3/4" x 1 x 3" (corner braces) white pine
2 27" x 2 x 4" (cross boards) white pine
2 7 1/2" dia. x 3/4" (bearings) white pine or plywood
2 2 3/4" dia. x 3/4" (bearings) white pine or plywood
2 1 1/2 x 2" hinges
1 small hasp
1* 1/2 x 40 1/2" steel rod
8 1/4 x 1 1/4" stove bolts
12 1/4 x 1" stove bolts
28 1 1/2" #10 wood screws
4 1/2" washers wood glue
approximately 1 pint of flat black paint
* these lengths will depend on the length of the barrel you use.
Construction:
Drill a 1/2" hole in the center of both ends of the drum. Has to be
the exact center or the barrel will wobble when you turn it. You can use
a carpenters square and a stick to make a center finding device. Clamp a
straight stick to the square aligning it along the inside and outside 90
degree corners. Place this up against the barrel and draw a line along the
stick crossing the guesstimated center of the barrel. Spin this device around
the barrel a quarter turn and draw another line. Where they intersect is
the center of the barrel. Do this for both ends.
Next, draw the outline for the door and mark the location for the hinges
and the hasp. Drill out the mounting holes for the hinges and the closing
hasp, then cut out the door opening. Drill a small hole on the door line
where the hasp will mount to get the jigsaw blade in and just follow around
the line. Putting the starting hole at the hasp location will keep it hidden
and just looks neater. Take a file or rasp and round off all the edges so
you won't cut yourself later. Attach the hinges and the hasp using the 1"
stove bolts. If the barrel you're using has ribs you'll probably have to
cut a V notch in the ribs on the door so it'll open all the way. The small
holes left from this shouldn't cause you much problem with stuff falling
out as it
turns.
Now make the circles used to support the drum and keep it centered on the
supporting frame. You can use Pine or plywood, whatever you have available.
Mark out the two circles, one 7 1/2" and the other 2 3/4" in diameter
on one piece of wood and clamp the second piece underneath. Mark out the
four mounting holes on the larger circle about an inch in from the edge
and drill them out with a 1/4" bit. Mark and drill out 1/2" holes
in the center of both circles. Cut out the circles with a jigsaw. If that
1 1/2" of wood is too much for your jigsaw you'll have to do them one
at a time. At this point the center holes can be used to line them up on
the 1/2" steel rod. Simply trace around one circle onto the other piece
of wood and everything will line up properly in the end.
Once you've got the circles cut out slip them over the steel rod to get
them aligned and glue a small and large circle together. You can either
screw them together or just use a clamp or two to hold them while the glue
sets up. Try not to use too much glue so that it doesn't squeeze out and
glue the circles to the steel rod! Once the glue has set up or if you used
screws to hold them together you can mount them to the barrel. Slide the
rod through the holes in barrel and slide a circle pair on. Holding it steady
drill through the 1/4" holes you've already got and through the barrel.
Slip in 4 of the 1 1/4" stove bolts and then reach inside to screw
on the nuts. If you didn't round off the edges of the door and door opening
earlier now would be a good time! Long arms and paitence are helpful here.
One builder of this composter used 5/8" holes in both the barrel and
the wooden circles. Into this he slipped 1/2" pvc piping with the thought
that the steel rod wouldn't be exposed to the composting materials and rust
with the moisture. He also cut the rod about 2' longer than needed and bent
it at a right angle where it came out of the supporting frame and another
90 degree bend about 6" from the end to provide a handle for turning
the barrel. Slip a small piece of the pvc onto the handle end to keep any
rust of your hands. If you do this you'll have to drill a hole through both
the smaller wooden circle and the steel rod and slip a pin of some sort
through it to lock the barrel to the rod. A long nail will work well here.
Now we'll make the supporting frame. Cut the 2x4's to length, 4 of them
40" long, the frame uprights, and 2 of them 29 3/4", the frame
horizontals. Cut lap joints the glue and screw them together. To cut a lap
joint see construction tips. The uprights will also need a dado cut into
them 23" up from the bottom. Measure your 1x3 boards but the dado should
be about 3/4" deep by 2 3/4" wide. Cut this dado the same way
you cut the lap joint. Make sure you cut it on the outside edge of the 2x4!
It always helps to lay out the supports on the ground, then mark where you
want the dado cut. Remember, measure twice, cut once.
Your drum will be approximately 34 3/4" high + 3" of wood circles
for a total of 37 3/4". Add in the width of 2x4 frame horizontals,
3", and you've got 40 3/4". A pair of washers on each end will
help the turning of the barrel so lets add another 1/2" for 41 1/4".
The outside of the frame horizontals should be 41 1/4" apart so cut
the 1x3 to this length. If your barrel is not 34 3/4" you'll have to
adjust your measurements to match. An easy way to measure, especially if
your barrel has flared ends is to slip the steel rod through keeping it
flush with the plywood circle at one end and placing a mark on the rod flush
with the wood circle on the other end. Slip it back out and measure it.
Add 3 1/2" and this becomes the distance the outside of the frame horizontals
should be. Cut your 2 1x3 braces to this length. Glue and screw the 1x3's
into the dados.
Drill a 1/2" hole through the center of the horizontal frames. This
should be about 14 7/8" in from the end and 1 3/4" down from the
top. Placing it only 3/4 or 1" down from the top wouldn't hurt by providing
more solid wood underneath the hole.
Now cut and attach the 4 1x3 corner braces. They should be 23 3/4"
in length and cut at a 45 degree angle on the ends. I'm not sure the 23
3/4" length is right from the math I'm doing so... Measure out along
the 1x3" brace 17" from the outside of the vertical frame and
mark this point. Lay a piece of 1x3 across this mark with the other end
on the top of the vertical frame. The top edge of the 1x3 should be on the
mark and at the corner of the vertical frame and overhang past the vertical
frame so it is completely covered. Clamp temporarily and trace the outside
edges with a pencil. You should have three marks, one below the 1x3 brace
and two on the top of the vertical frame. Unclamp and cut this piece along
the lines. Reposition it to be sure all is well and if it is use it as a
template to mark and cut out 3 more the same. Glue and screw these in place
making sure the whole frame stays square. The distance between the tops
and the bottoms of the vertical frames should be the same at 41 1/4"
or whatever your measurement was.
Now, to mount the barrel in the frame. You can either lift the barrel
into the frame or set the frame down onto the barrel. Being a small guy
I'd probably set the frame on the barrel. Less weight to support and I could
do it by myself. Slide the steel rod through the barrel and slip two washers
onto one end. Lower the frame down and push the rod through the 1/2"
hole in the frame. Half done. Push the rod farther through and lower the
other side down. This will get interesting trying to get the two washers
in there but persevere. Ease the rod back through and get the washers on
the rod and then slip the rod through so it's even on both ends.
So now your barrel composter is lying on the ground with it's feet flying
in the air. You may need help but 'roll' it onto it's feet. Give it a good
spin. It'll feel good! If you find that the steel rod wants to screw it's
way out of the holes in the supporting 2x4's simply tack a small piece of
wood across the holes and that'll stop it. If it squeaks, a dollop of oil
inserted over the washers will stop it. You may want to add two cross braces
to the 2x4 supports for even more rigidity. Only put two on for now and
make sure they go on at a good angle to provide the triangle the makes things
rigid. If you haven't already, paint the barrel flat black to help soak
up heat from the sun. Drill a couple rows of 1/4" holes in the barrel
to allow for drainage of excess water. When using the composter make sure
you leave it with these holes at the bottom so the excess will drain out.
Paint the frame for prettiness if you want but it's not necessary.
I've not built this beast but in thinking about it while writing this you
should be able to just push your wheel barrow up under the thing to empty
it. While loading it the door will have to stay open so either rig something
to hold it open, a string?, or position the whole thing so the hasp side
of the door is up when facing it, exactly opposite to the drawing above.
This will allow the door to just hang open. I also wonder about drilling
a number of 1/2" holes in one of the 7 1/2" circles and another
1/2" hole in the horizontal frame that lines up with these holes. That
would allow you to slip a bolt or dowel in to hold it in position while
loading it. I imagine while unloading you'll want it free to spin to help
shake the finished compost out and into the wheel barrow.