The Birds & The Bees: bird bath

Using the lessons I learned from the last birdbath I poured, (see that project here: http://kathyfreeze.blogspot.com/2014/08/making-it-way-you-want-it.html, and here: http://kathyfreeze.blogspot.com/2014/08/success-is-in-eyes-of-beholder.html),
I decided to pour the second one this week. I've been asked by a few people how I did it, so this time, I'll list the supplies and a few more details.
First, determine what shape you want. I found my planter pot saucers at Lowe's for about $5 and the large one is just the right size for the bath that I want.
I use this 'Quikrete' concrete mix (already has the appropriate sand and concrete blend) which can be used for paving bricks.

I also add this Concrete Acrylic Fortifier - it helps increase bonding and water resistance. For color, I like the 'Terra Cotta' color, but there are others available. All of these things were purchased at Lowe's.

This time, we're using sand. Much easier to work with. Normally, it's recommended to use "Casting Sand" when pouring concrete molds, but we're using 'Paver Sand'. The Casting sand is not available around here and, after finding it online and seeing the price, I was quite happy to just work with the paver sand.

Bob framed up a box that is approx 4-5" bigger than my mold, to help hold it all together.
First things, first - find a place that is in the shade all day, so you can work comfortably, and also has a source of water nearby. You will also want your freshly-poured birdbath to be in the shade for at least 48 hours, so that it doesn't dry out too quickly.
Since I'm making a total of 3 bird baths and I want the water to flow from one to the other, I also added pour spouts on each of mine. The bottom one will pour into a 5 gallon reservoir, in which I'll place a water pump to pump the water back up to the top bath. If you're just making a simple, single bird bath, you don't need a pour spout.
Place your chosen tray upside down in your box, then pour in your sand. Wet the sand thoroughly. You will need something with flat sides with which to pack the sand (I used the small stick in the picture to pack it with), then hollow out every place you want concrete to flow into. I found a trim tile piece to use for the shape of my spout. Make sure you wrap it with Saran Wrap, or you will have a heck of a time getting it unstuck from the concrete.

My planter tray, turned upside down, the piece over which I'll pour the concrete for the spout, the stick I use to pack the sand down, and the wooden spoon that I scrape around the outer edges to shape the sides of the bath.

A closeup of the tile piece I use to shape my spout. This was exactly the shape & size I needed for my spout. Wrap it in a non-stick material, so you can remove it after the concrete hardens.

I used a wooden spoon to pull out the sand around the edges of my mold as it was just the right thickness for my bath - about 1.5" wide and I could ensure my sides would be even. You can adjust your bath to be more shallow by leaving more sand around the edges of your mold (the trough area), but for me, it was easier to just adjust the depth of it by making my spout higher or lower on the side of the pan. Now is a good time to place any decorations for your bath on top of the mold and in the trough areas. Last year, I used leaves from my sycamore tree and cucumber plants. Remember - you have to think 'upside down' when you're carving your mold out of the sand. It's also really important to pat your concrete down into the mold as you pour it, so that you don't end up with creases and air voids (see the pour spout on the bath below as an example of what it will look like if you don't pat it down enough). I did a great job around the edges of this bath, but the spout came out kind of rough looking. I try to work quickly with this stuff, because I'm afraid it's going to setup before I can get it tapped in. Lesson learned - slow down and work each edge thoroughly.
For this birdbath, I used scraps of stained glass that I had been saving. After turning the bath over (we waited about 24 hours), I found that the concrete had slid under the glass and encased it. Thankfully, the concrete wasn't fully hardened off and I was able to scrape some off to reveal the glass underneath.

The finished bath - the overflow spout is kind of rough looking, but it's functional. Next time, I will use bigger pieces of glass also.

I poured the leftover concrete into a few smaller sized planter saucers that I had lying around to make some stepping stones for my garden. I also pressed some scrap stained glass into the tops of them, working them back & forth to get them secured into the concrete. The biggest mistake I made with these was the planter saucers are made of ceramic and I couldn't separate them from the concrete afterwards. So - lesson learned - either put down Saran wrap before pouring into a ceramic mold or use plastic molds. Make sure you look at the molds you choose very carefully. The concrete tends to take on the features of your mold very nicely (look at the ridges in the picture above), so make sure you like the designs in your chosen mold - because that's what you're going to see when you tip the bath out.