Friday, February 6, 2009

Styrofoam Graves – Basic Cutting and Shaping Foam

There are a million ways to do these, but once you get started, be careful… it can easily become an addiction, and before you know it you will have to rent space in your neighbors yard in October of every year.

Here’s my method, including some “Not To Do’s” that I learned this year – just for scientific purposes, of course… for sharing with the world!  (And NOT because I’m an idiot… Noooo, of course not)

*Note:  This info is provided from a perspective of someone who buys materials in the South, where the thicker sheets of insulation cannot be found.. therefore, we have to double our work in order to get a realistic thickness.  I am dealing with 1/2” thickness of foam here – so if you live in the North, skip all the doubling.  Just cut your 2” sheet, and be thankful for your winters.  :D

1.  Sketch your idea for the shape.  I do this on graph paper, which helps me keep dimensions in proper ratio.  I also use a yard stick, and various objects such as butter bowls, or square Glue jugs for different shaped corners.  If you are just starting out, and don’t want to freehand it, HERE are some great templates from

2. Gather materials. 

  • Styrofoam insulation sheets – the pink or the blue kind.  An 8’x4' sheet runs for about $9.50 here.
  • Cutting method of choice – either a long serrated bread knife, box cutter, or The Wonder Cutter, as you prefer.  I use the box cutter for long straight cuts, then the WC for the detailed work.
    • Note on Wonder Cutter – I had the battery operated one, and I didn't care for it – then I bought the AC Powered version, and WOW, what a difference in cutting, as well as the straight “pin” style made it really easy to navigate any detailed cuts.
  • Liquid Nails – to glue second thickness to the front panel
  • Monster Mud or just plain Joint Compound
  • Fine grit sandpaper

3.  Transfer your design to the Styrofoam.  I tape several sheets of computer paper (8 1/2x11) together to form a big piece of paper the size of my grave, draw the shape I want on it, then attach to Styrofoam to the foam with tacks to reduce slippage, and “cut out” the shape with an Xacto, leaving an indented guide for where to cut.  If you have a more basic shape, you can just take a box cutter and cut the whole thing out in this step.

4.  Cut out shape with your choice of tool.  If you use a wonder cutter, try to hold it as still as you can down the straight line, or you will get jaggies.

5.  Repeat step 3 and 4 to create the back piece – just for realistic thickness.  Then line the two pieces together, and glue with Liquid Nails.  Try to get good coverage on the edges, so there won’t be a big gap.   I then set heavy things on top to dry, or even clamp, if you have clamps that won’t cut into the foam.  Halloween thru Christmas 2008 010 Halloween thru Christmas 2008 057

I had to clamp the ends on the top picture.. they were very skinny points, and didn’t have enough surface area to put enough LN to hold it together.  On the bottom picture, I am using paint cans as weights.  I used scrap foam in between the grave and the can, in case the metal lip of the can dented the foam.

6.  Once that has dried, I used joint compound or Monster Mud if I had some already made, to smooth down the seam on all sides of the grave.  This is where I found out how annoying the jaggies from the wonder cutter are… once the MM dries, sand it with fine grit sand paper to get it as smooth as possible, without making the seam obvious again.  Halloween2 004Halloween2 003  On this one, I went a little nuts and applied Monster Mud over the entire back of this thing, for a stone texture.  Probably won’t do this again for graves, because I didn’t want to mess with the front – keeping it out of the lettering, but its a cool technique.

Once you are happy with the smoothness of the edges, there is no visible seam, and everything is dry, you are ready for carving your lettering and details.

**Note, it is at this step that most people will drill pilot holes in the bottom of the graves, to place the grave over rebar, which is pounded into the ground.  This is where my NOT TO DO comes in.  We didn’t do these holes at this point because A) We don’t own a drill bit even close to being that long, and the $100 or something cost of the bit just freaked me out, and B) I couldn’t figure out how to go up the middle, when the middle of these thin little dudes was a line of Liquid Nails.  So I carried on, with no plan, figuring I would figure it out later.

For someone with better plans that that, go visit The HowloweenQueen for MUCH better instructions… or there’s also Aidtopia – Halloween, which shows us the embedded PVC pipe method.

Next installment…. Lettering and Detail.

1 comment:

Ghoul Friday said...

It's the what-not-to-do points that are the MOST important lessons learnt and shared, and how you adapted instructions when you just didn't have whatever was called for. Thanks for posting this. I think many people will find it useful.


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