I needed to make fake intestines for a movie I'm making, this is how I did it.
Step 1: Gather Materials
needle and thread
poly fiber pillow stuffing- (just go buy a cheap pillow)
red, blue, and black pens and markers
I decided on using white hosiery, it seems like intestines are usually pale in color compared to the other organs. Plus if you start with white you can change your project to any color you like. My friends daughter had outgrown a pair of white hosiery so that part was free. I took polyfiber stuffing from a pillow, it's synthetic and I think it'll hold up over repeated uses involving fake blood etc. Needle and thread, I used white cotton, maybe I should have used a synthetic for durability? Blue ball point pen for veins, red for arteries and a red marker for larger colored areas, then a black marker for recessed areas. I top coated the whole thing with liquid latex as I plan on reusing it. I also think it'll make the prop have a more realistic look, otherwise the fake blood might hide all the fake veins when it soaks in?
Step 2: Stuff Your Guts
I tore out lose clumps of the fiber from the pillow and made balls about the size of a tennis ball. It's lite fluffy stuff so when it goes in the hosiery it'll compress down to the size of a golf ball. I rolled the hosiery back on itself to make it easier to stuff. Leave some space between clumps, intestines have a segmented look. Once you get a foot of length stuff start sewing so you don't loose the spacing.
Step 3: Sew Your Guts
I looked at some pics of human intestines online and noticed the large intestines seem to have a cleft in the center and they seem to bunch up every two inches or so. I start with sewing the middle, skipping a half of an inch every other pass. When I've made a cleft an inch and a half or so, I wrap from the center around the outside edge to bunch it up, then go back to sewing the cleft. Once you reach the end, go back to stuffing and repeat. I did both sides before dealing with the center. The center of the hosiery is the waist support and isn't tube shaped. I cut the waist half off, wrapped it around more stuffing and sewed it up. It doesn't look as good, but it worked.
Step 4: Draw Some Veins and Arteries
I used a blue ball point pen and a red dry erase marker, because that was all I could find. I think permanent markers would have been better, but I do like the veinyness of the blue ball point pen. I used a larger red marker to add the red to deeper areas, then I used a black sharpie for added depth. I knew top coating this with latex would obscure the marks a bit and make them look more realistic, plus the latex will protect the inks from the blood and water.
Step 5: Top Coat With Liquid Latex
Now just brush liquid latex over the whole mess. If you are using the prop just once you might skip this step, but remember the blood will most likely make the intestines a solid red and all the veins will be hard to see.
Step 6: Add Connective Tissue and Another Layer of Latex
I was having fun making mine so I made connective tissue. That's the thin tissue film that sort of holds our intestines and other organs in their general arrangement. For this I painted latex onto a candle and when it was dried, peeled it off and adhered it to the intestines with a dab of latex. I used a candle because the latex will release easily. You might use some ky jelly on a flat smooth surface or wax paper. Dusting it with baby powder will keep it from sticking to itself. I didn't care if it looked stuck to itself, so I just tore it off and adhered it as it was. Top coat for a good seal to make sure it is protected. I have fun making this stuff, but I'd rather get some mileage out of it over remaking it every time I need a prop. The latex will dry rot with time, and I might opt to top coat that mess with fresh latex, it might look more realistic after some aging. If I need to re make this project, or if a friend needs to make some, I can reference this instructable. Thanks instructables!
Step 7: Add Some Blood
I used stage blood to top coat, I'll add some more when we shoot the scene. The over all look is better than I imagined it was going to turn out and it will be reusable. I don't use corn syrup and red food dye anymore since it stains everything and makes a sticky mess that will attract bugs. The stage blood costs a little, but it saves you much more. I'll make another structable about the body cavity rig with blood squirter I used in conjunction with this prop. Cheers, thanks for looking.