I was asked to make a western gatepost for a Vacation Bible School similar to this.
I started by making a box out of 1/2 inch styrofoam.
I formed it around a 1/2 inch plywood bottom. I cut an 8 foot 1x4 down to 6 1/2 feet. Then I screwed it to a piece of 2x4 and screwed the 2x4 to the bottom of the plywood. I put the screw through the bottom of the plywood up into the 2x4 so the point of the screw wouldn't be sticking through the bottom.
Next I cut two 6 inch strips of the 2 inch styrofoam. I hollowed out the inside with the heat knife so they would slide over the 1x4.
Measured them to make sure I cut out enough.
I used wooden skewers (which you can find in the grilling section of the grocery store) to keep the two pieces together.
Then I distressed it by rounding the edges and making cut marks in it.
I cut grooves to make it look like wood.
Then I glued the two pieces together using caulk and wooden skewers. And worked on the other pieces.
I forgot to take a picture of it, but in the cross beam I hollowed out about a 4 inch section so the 1x4 would slide into it.
You can see in this picture where the cross beam will fit on the left column.
I cut out a support beam and distressed it like the others.
Then I made it square so it would fit between the crossbeam and the columns.
I secured it to the column with caulk and wooden skewers. The crossbeam is just resting on the column.
I made sure everything fit.
Next I started working on the stones. I cut a piece of 2 inch foam in a size square I needed, then cut that piece into smaller blocks.
I used the heat gun to roughen up the edges and make them look more like rocks.
I did this for all the sides and the tops. 10 large pieces of foam in all. I laid them out in the pattern I wanted and made sure they all fit.
I then marked the back of each one so I knew which pattern they went with. I also took a picture of each pattern in order so I knew how it was laid out. This step saved me lots of time later on.
I marked each stone with the color it was to be painted. This way I could keep the colors from being too close together.
Here it is before the detail painting.
I took the stones and stacked them according to color, and painted them all. Then I dry brushed a darker color on the grey and sandstone color rocks, and a lighter color on the clay colored ones.
I matched up where they would go and caulked the back side and put them in place.
This is the final base. The post slides off of the 1x4 and it can be transported and set up anywhere.
I painted the posts and crossbeam with a wood brown color and the cutout parts with a dark brown. I dry brushed the same dark color on the distressed parts of the wood also.
This is the final product.