Build Columns with SonoTubes and Pool Noodles
That's an 8-inch concrete form tube from the hardware store, which costs about $8. The noodles were 70 cents each (on clearance at a dollar store), and we ended up using six of them. Add in a quart of contact cement, some scrap wood, and paint that we already had, and our column ended up costing us around $20 instead. Even if you had to buy the wood and other supplies, though, you'd still be well under $50.
So let's get to it!
Start by cutting all of your noodles in half with a long utility blade: Don't worry if it's not exact; just do the best you can.
Lay out one of your cut noodles on the tube, arranging it into a spiral curve. When you're happy with how it looks, have a helper draw a line beside it with a Sharpie. (This will be your guide line when it comes time to glue down the noodles.)
You could also lay the noodles out straight, though, if you don't like the spiral look.
Next, paint the cut edges of your noodles and the surface of your concrete tube with 2 coats of contact cement, allowing them to dry for each coat. (You should find contact cement at any hardware store for less than $10 a quart.)
Contact cement is awesome. Once it dries it only sticks to itself, so you don't have to worry about snagging anything you don't want to - but once it sticks, it forms a permanent, ultra-strong bond.
Now the fun part: sticking your pool noodles onto your tube. Line up your first one to match your guideline, and press down firmly
Note that you should start about five inches down from the top of the tube: this gives you room to add a column cap later. (Plus the noodles aren't long enough to cover the whole tube if you curve them.)
Now just keep adding on noodles.
Your last noodle may be a bit of a squeeze, but jam it into place as best you can:
The pink noodle was the last one placed. As you can see, it's a bit smaller from being squished into place, but not terribly noticeable.
Next you'll want to trim the edges of all your noodles. Here's the easiest method we found to mark a straight line all the way 'round:
Rotate the column while a helper holds the Sharpie, supported by a shoebox.
Trim off the edges with a utility blade, and you'll have a nice noodle lip like this:
From here you have a couple of options for finishing off the ends of your column. Some people cut wooden rings to slide over each end like a cap.
You can wrap the sides in a thin aluminum, but you can also use wood veneer, flexible plastic sheeting, or even a heavy poster board to do the same thing.
Fitting the new cap. See how much taller the new cap makes the column? Oh, and we've already sprayed on our first coat of primer here, too. Use a plastic spray-primer, or a good quality one like XIM.
All that is left is adding a round topper.
You could also make it square; I just liked it better round on top.
To finish off your column, caulk in all the lines...
And follow up with a good coating of spray texture - the same stuff you fix wall patches with. (The pool noodles actually have a great stone texture already, so no need to spray those unless you're trying to match the texture to your caps).
And finally, paint!
This column was brushed on with a cream colored wall paint, and once that dried it was brushed on with thinned down brown craft paint, which immediately was wiped off again with a wet paper towel. That added just the right amount of aging to the texture, and really helps sell the stone/plaster look.
The end result is incredibly sturdy, and with the wood base & cap weighs a good 15 pounds, so don't worry about it tipping over too easily. Alternatively, you can insert a bag of sand.