I had hoped to have some pics of the process for you, but unfortunately my camera couldn't pick up the grid on the poster board nor did it want to pick up either the stencil making process or the stencil tracing process so you're going to have to use your imagination for those bits.
Transferring the pieces was really easy. The poster board was marked in half inch squares and my scale on the graph paper was 3 inches to a square. That translates to 1 graph paper square equals 6 poster board squares. Pretty easy, really. It's mostly just a bunch of counting. Granted, that doesn't mean you won't mess up at some point. I managed to do that very quickly. Happily, I caught it before I started cutting anything. Remember, you only need one stencil per piece so your layout isn't going to look like your foam board cutting layout. You can make a layout for the stencils if you want, but it's a little easier to eyeball. If you use pencil and mark the points of each piece it makes it a lot easier to shift things about so you can cram as much as possible on the poster board sheet. Once you have the pieces roughly marked out, you can use a straight edge to draw in the lines. Then double check your measurements on every piece. It's really easy to make a mistake so extra checking is a good idea. If something doesn't look right, it probably isn't, so measure it out again.
If your luck runs like mine, you're probably going to notice a small problem at some point. You see, the standard size for foam board is 20x30 but the standard "full size" poster board is 22x28...because they hate me. I swear the crafting world is as bad as science when it comes to "standard" numbers. There's one type of sample that routinely infuriates me at work because of "standard" numbers. To process a certain type of sample it has to go through 5 different types of kit and NONE of the numbers match. The first kit comes with enough material to do 50 samples, you can't get less, but the second kit will only do 20 samples and then only if you do them all at once (they short you on one component so to get full use out of the kit you have to use the whole thing in one go) and one step requires that you put the samples in a magnetic stand which come in strips of 6 (20 isn't divisible by 6 so you have to have 4 stands). Then I have to check and make sure the samples are good and that happens in groups of 12. All that before I use the kit that lets you put in on arrays, which does 24 samples, but requires a centrifuge step and my two centrifuges hold 18 and 30 samples, respectively. The you have to put them on the arrays, which happens in groups of 6, 8, or 12 but you have to buy a minimum of 12, 16, or 24 because they don't come in 1 packs. And people wonder why I'm so good with organizing stuff. The lab would be chaos, otherwise. So, much like I do at work, you have to tweak things to fit your needs.
I have 2 stencils that have to be larger than 28 inches which obviously is not going to fit on 1 piece of poster board. That means I have to split my stencils. It's actually really easy to do on the gridded poster board. First, decide an easy spot to split the stencil. Then mark out all the pieces but leave an extra half inch on any side that has to connect to another piece. Once you get your pieces cut out just overlap the half inch tabs, tape it all together, and you've got a full sized stencil.
To transfer the stencil outline to the foam board, hold the stencil securely as you trace them one at a time. You can try using a bit of tape to hold the stencil down but I found that the tape made it harder to get the stencil positioned.. Once you get all your pieces traced out, COUNT THEM ALL AGAIN! After you've made sure you traced out the correct number of pieces you can start cutting them out. I used an Xacto knife to cut out my pieces. Whatever method you use, just be careful. Xacto knife cuts hurt a lot more than you think they would. Happily, the one that got me the other day was nice and sharp so it healed up in no time, you can barely see the scar, but it still hurt!
You need to be a little careful with the cutting out process. Sometimes the foam core catches and doesn't cut smoothly. It can cause your cutting tool to bind or deflect off in an unwanted direction so take it nice and slow. If your cutting blade catches and you manage to prevent it from slicing the wrong way it can still cause unsightly dents in your cut edges, as shown below.
Once you get your piece cut out you can move on to the fun part, painting! I'm not going to focus on the door base for this part, it's all uninterestingly one color so there isn't much to show there. Instead I'm focusing on the frame because it has a lot more detail and so should be more informative.
Spray paint makes painting a lot easier; it will give you a smoother coat than a brush will and it dries a lot faster than other paints. By painting all the pieces before they're assembled it ensures that I don't get paint where it doesn't belong. Just make sure you have room for everything to dry. If you stack your pieces before the paint has dried completely they can stick together and mess up your paint job. The spray paint can will tell you how long the dry time should be. Plan on a couple days for this part. I always need multiple coats to make spray paint look nice and I try to do things in color groups so that there is no trouble with over-spray. It may be necessary to paint the foam board on both sides because it can warp when it gets wet. 1/2 inch foam core is a little harder to bend so it's less of a problem but 3/16 inch foam board likes to warp but painting both sides seems to help undo the warping.
|A piece of door frame with the yellow base applied|
|Using a straightedge to put down the painters tape|
|A completely taped piece|
|After painting the black layer and the painters tape removed|
|I had to use my colored diagram to make sure that the color alternation continued beyond each seam|
|One side of the door frame|
|These are the paints I used for the door frame. I stumbled upon the Krylon Fluorescent completely by accident but it happened to be exactly what I needed to make the door look right.|