I've been doing holiday standees in 1/2" plywood for the past two years (inspired by the Ginger Bread Man project). Plywood is not well suited for weather exposure.

I've used thinner corrugated plastic signs and h-frames for our community signage/notification, and they are flimsy at a small size. The thicker corrugated plastic, even at larger dimensions, is quite rigid. So this is my first attempt at using the thicker plastic for a holiday standee (rather than plywood). I've found the jig saw easier to work with than a Dremel rotary on plywood. For the corrugated plastic, I first tried the Dremel Versa Flame... that was disappointing (didn't cut through easily and melted the edge around the cut). Next I used the Dremel rotary with the cut out attachment (though the plunge router attachment may provide better control). I'm going to try a different bit next time, as this one left a lot of plastic burs around the edges. Not a big problem, just takes some time to pick them off. I tried sanding them off, which works, but you don't want to sand the flat surfaces of the plastic (It will negatively affect the paint job).

Step 1: Parts and Tools

10mm 3/8" Corrugated plastic sheet, length and width pending your intended standee size
H-frame (for smaller standees)
1/4" or 3/8" Threaded rod (for larger standees). Less than the height of the final standee, plus 6"
Various paints (preferably outdoor, weather resistant)
Various brush sizes
Clear sealant (if not using outdoor paints).
Rotary Tool with Multi-Purpose Cutting Guide attachment or a jig saw or a plastic sheet cutting tool
Carbon Paper and a pencil (if transferring an image)
Computer / Printer / enlargement software (if transferring an image)
6" to 12" black pipe cleaner (optional)

6mm plastic sheets seems more in-line price wise with plywood (based on 4'x8' prices). I haven't bought/tested the 6mm sheets yet, so I don't know much more rigid it will be than the standard 4mm yard signs.

Step 2: Enlarge an Image to Use As a Template

Find an image you want to use, or (if you have artistic talent) make you own. I use a poster enlargement method and transfer them image using carbon paper. For this project I used a Minion dressed as a vampire.

Print an enlargement or poster print of the image in order to tile it across multiple pages. (I went a little smaller for this test, tiled across only 6 pages. 3 wide, 3 tall).

Some print drivers have a poster option under the printing properties. Or you can download a dedicated application to print poster size. Adobe Acrobat also has an option to print as a poster.

I cut and tape the tiled pages together. (In the past I've printed using an optional 1/2" overlay between tiles, but I now find it easier to use 0 as the overlay. It simplified cutting and taping together).

Step 3: Trace the Image Outline Onto the Plastic

Using an appropriately sized plastic (consider the poster size and your intended final size), tape the assembled poster pages to the surface of the plastic.

For the orientation of the plastic, make sure the corrugated channels (the openings going all the way through the board) are positioned vertically (up and down). This is where the H-frame of threaded rod will go through, to keep it upright on your lawn.

Slide a piece of carbon paper in between the plastic and poster template. Using a pencil, trace the outline of the image. Shift the carbon paper as needed. The black side should face down as you trace.

Step 4: Cut the Outline

Remove the printed poster template.

Using a jigsaw or rotary tool, cut around the outline that has been traced onto the plastic. (You should practice on scrap piece first).

When cutting is complete, use clippers or scissors to remove some of the plastic burs on the edges. Some you'll be able to just pull off with your fingers. I had a little success using a sanding bit on the rotary tool.

Step 5: Apply Primer (optional) and Paint the Larger Blocks

Primer is optional, as the corrugated plastic takes paint very well. If you do prime, after it dries, give it a very light sanding with a sanding block.

If you plan to skip the primer, you can combine the two tracing steps (Outline and finer details). The only draw back is possibly smudging a pencil line of the finer details, when cutting out the outline.

I would still plan on doing the large blocks of paint, and than proceed with the detail.

Step 6: Trace the Finer Details

Trim the printed poster to remove everything past the outline. Re-tape the poster to the plastic, lining up with the cut edge. Slide the carbon paper underneath, and using a pencil trace around the details of each color you will be applying. Shift the carbon paper as needed.

I find it easier to focus on the larger blocks of color first, and than come back to this step after painting, to trace additional details or freehand.

Step 7: Paint the Finer Details

Paint the larger color areas first.

Than go back and paint the finer details. In some cases I reuse the poster and carbon paper to trace fine details, in others I just free hand it.

Craft paints are easy enough to work with, but on other projects I've also used cans, spray, and what ever I've had laying around. I only learned recently that there an acrylic craft paint that is outdoor and water resistant.

I like to also paint the back, as to maintain the basic appearance if walking past it. I just use much less detail on the back.

Step 8: Seal (optional Depending on Your Paint Choices)

When painting is complete, I use a clear urethane to weather/rain proof the paint. Craft paint (in my experience) will fade and not all of the paints I used were water resistant. The urethane (in the past) has held up well (but you might need to reapply every two years). I used a single coat on both sides. Be sure to stir frequently, or it will leave a yellowish tint.

Step 9: Final Steps

If you went with a smaller size, an H-Frame will be sufficient to keep it upright. H-Frames are designed to raise the sign above the lawn. I used a pair of clippers to remove one of the horizontal bars from the H-Frame. This longer part gets slid into the corrugated channels. Now insert into the lawn, and it will stand up right.

If you went with a larger size, an H-Frame will not keep it standing upright. Two or more threaded rods will keep it in place and keep it from flexing. Find an length of rod less than then height of your standee, but add approx 6 inches for insertion into the ground. Unless the ground is soft, you may need to hammer the rod into place. Adjust the rods so they line up with the corrugated channels, and slide the standee into place over them.

Step 10: Add Pipe Cleaner "Hair" (Optional)

You'll need 6" black pipe cleaner. I had 12", and cut it in half. Tie a knot some what in the center. This will keep it from falling all the way down the corrugated channell. Insert one end into the channel, space how you like. And now your minion has hair.