As a guard player, I have a lot of vehicles....scratch that...I have A TON of vehicles so explosions are inevitable. So I've come up with a simple solution to the "..or a suitable piece of terrain." statement in the rule book.
I made all ten of these wreck craters in about 3 hours total from start to finish. These are updates form my old markers that were just really quickly thrown together from foam core board and sand. They did the job these do, but were falling apart and warped bad when I made them so I figure if I had to make more I was going the whole nine yards with these markers. And let me tell you, they turned out awesome.
To start I gathered materials. I had a bunch of scrap 1/4" MDF board from making the lining of my new army bag so I just used that. After that you'll just need basing material, bits, and wood glue.
I first measured out my chimeras. They are 4.5 x 3.5 so I just cut up a long strip 4.5" wide then chopped it every 3.5" and made 10 similarly sized rectangles. They aren't exact but that doesn't really matter, they really don't need to be.
After that I slathered wood glue on the "rough" side of the MDF. The rough side allows the board to absorb the moisture of the glue and for it to dry faster and adhere better. MDF has a really shinny smooth side and very rough unfinished side. Make sure to use the rough side.
I used a sand mixture I made after talking to OST about what he uses for his dirt/sand/rubble mix. He told me just just used a bunch of different sized rocks/sand/pebbles and mixed them all together and just had a huge bucket of basing material he'll never run out of. I didn't go so far as to make 5 gallons, but I ran down to Micheals and bought up a bunch of different sized sands (the kind they use in the sand art jars) and then went to the fake flowers area and got some different sized small pebbles (like they use to fill vases). The result is a really nice looking mix of mostly fine to coarse sand and randomly placed larger "rocks"
However, before I lay down the rock mixture I needed to put in debris. For this I just scooped out the bottom corners of my bits box for all those random tiny bits that I'll never need or use. I dumped them in a container and then took the tiny broken chunks of my floor tiles from when I model slate or slabs of concrete on bases and mixed them in with the bits. The result of the bits mix and the rock/sand mix together gives me large debris left over from an explosion and then bare earth under it.
To put down the debris I first spread over a generous amount of wood glue thinned slightly with water. Then I took a small pinch of the bits/tile mix and sort of sprinkled it randomly and sparsely. The tile should be only 20-30% debris.
After that I took a scoop of the rock/sand mixture and shook it a little to get the sand to settle to the bottom of my scoop so that I can sprinkle the larger pebbles on first. If you don't do this, the sand just hits the glue first and then the larger chucks don't have anything to stick it. Its sort of an art, take a few practice shots at it on scrap material before you use it on a board you've put bits on.
After that I just shook off the excess and put it in front of the fan to dry. Drying took about an hour. After that I carefully inspected the craters for any bits or pieces of tile I thought might fall off during travel and use and general abuse they'll go through and added just a drop of super glue to help hold them down.
From there its up to you how you want to paint them. My old ones were grey and black so I wanted to try something different (because my Guard theme color is grey and black, it sort of blended too much) so I went with the brown.
I used folk art to paint the craters. There is no reason to use your expensive GW paint on terrain so go out and buy the .99 bottles. After painting and sading the earth texture, I just when back with black for all the bits and dry brushed silver on them after that. Then a heavy layer of brown ink to make the metal look rusted/weathered/exploded/ect. and done!
As a final note, I suggest just making one size marker. I had some Valkyrie shaped markers but they were just annoying to have to carry markers for my chimera and my Valks. As a person that loves multipurpose these craters really appeal to me in that they can be just set down next to each other to make your larger craters. For example, 2 set long edge together make a land raider and 4 can be used for a Valkyrie.
Well there it is. Simple,cheap and still awesome wreck markers! Please feel free to leave questions or comments.