Step 1: Supplies
-Duct tape: I used just over one roll for my friend, who is pretty tiny. You should probably have at least two or three rolls on hand.
-Shirt or plastic garbage bag (person sized): Whichever of these you use, it should be as long as you want your dress form to be tall
-Newspaper: lots for stuffing. I used almost two whole newspapers from Thanksgiving, so they were even fuller than usual.
-Permanent marker/pen that can write on duct tape
Step 2: Prepare Your Model
If you're using a shirt to make this dress form (Note: it will get cut and become one with the form), skip to the next step. If you're using a plastic bag, tun it upside down and cut a hole in the bottom just big enough for your model's head to fit through. Have her pull the bag over her head so you can judge how big & where you need to cut your armholes. Cut circles in the bag where your model will put her arms through. Try to keep the arm holes as close-fitting to your model's arm size as possible, as this will make constructing your dress form easier later on.
***This is a good time to pause for a trip to the bathroom. Soon your model will not be able to sit or move around easily without possibly damaging the dress form in progress.***
Step 3: Prepare Your Base
Continue pinning up and down the sides of the shirt or bag until you have two pinned "seams" that fit the shape of your model. If you have a larger bag that needs to be pinned in the arms as well, have your model hold her arms out parallel to the ground, then pin under the arms.
Once you are happy with your pin placement, cut on the outside of the pins (the side away from your model) in order to get rid of the excess material. You can put this to the side for now as you may need it for alterations later. When you are done cutting, you should have something that looks like a pinned together dress.
Make your side seams by removing one pin at a time, folding the material over flat and using the duct tape in small (4-6 inch) strips to secure the sides shut. Do this on both sides until you have no pins left in your shirt or bag. You should now have a form-fitting base on which to begin your dress form.
Step 4: Begin Taping
***Note: When taping your model, it is best to place the tape down on one side, then run your hand along the length of the tape to smooth it down, allowing the tape to follow the natural curves and depressions of your model's frame. This keeps you from ending up with awkward bunches and an unnatural form.***
You can now start taping across the bust. Begin just above your first piece of tape that went around your model, and tape horizontally across the bust and around to the sides. The length of tape you use for this step should be equal to the width of your model plus approximately four inches so there is tape to wrap around the sides. Continue taping above the last piece until you've covered the fullest part of your model's chest, or about four to five strips of tape.
Step 5: Shoulders
You are now ready to work on the tops of the shoulders and arms. If you used a wider bag or shirt that has sleeves, now is the time to remove them. Simply cut the sleeves to where the shoulder seam on a shirt would be (use your model's shirt as a guide, if possible) and remove the excess material. Begin taping over the shoulders by covering the exposed areas of your base. You can tape in all directions here, as the shoulders need to be sturdy enough to support the rest of the form once it is on the hanger. Get as close to the edge of the armholes as possible when taping over your model's shoulder; if you accidentally tape her or her shirt, it is best to gently pull the tape up now and fold the exposed stickiness under before it forms a strong hold on your model. Continue taping both shoulders until the base is covered.
Step 6: Coverage
Do this for both the front and back of your dress form. During the covering process, tape horizontally across the seams you created to ensure the sides of your form are as sturdy as your front and back pieces. Use strips of tape approximately 8-10 inches long for the side coverage so that they reach both the front and the back.
Step 7: Break: the Point of No Return
Step 8: Lower Half
After you've taped your base line, simply wrap strips of tape around your model, making sure to tape across the sides as well. Cover your base completely with duct tape, and inspect for any holes or missed spots in your dress form.
Step 9: Final Layer
Inspect one last time for missed sections or single-layered areas. This would also be a good time to mark the top seams on your dress form going from your model's neck to shoulder, as these markings will help you place your hanger later.
Step 10: Freedom!
I began at the top and cut down, but it's most definitely easier to cut from the bottom up. You can cut one straight line and be done with it, or you can cut in a zigzag pattern so that your two sides are easier to match up when you're putting them back together. Otherwise, you might have to match up tape strips like I did to ensure you're connecting the correct sections.
Don't forget to take your model's measurements after this step if you do not already have them. You should measure her bust, waist, hips, shoulder to crotch height (or shoulder to bottom of dress form length), and shoulder to floor height (if you're planning on hanging your form at actual model height).
Step 11: Inspection and Connection
Once you're satisfied with the sturdiness of your form, you can begin taping the back together by using short (2-4 inches) pieces of tape and carefully lining up the edges. Do this until the back of your dress form is completely taped together. For extra support, go back over the back seam with strips of duct tape placed diagonally and horizontally.
Step 12: Hems and Hanger
Shimmy the hanger into the top of the dress form as if you were hanging a dress. Line up the seams you drew on with the hanger and tape in place. If you didn't draw seams, adjust the hanger until it holds the dress in a manner than mimics your model's posture.
Step 13: Close the Gaps
For the neck hole, it is easiest to have a friend hold the form open while you tape the hole closed. Tape from front to back over the hanger until the hole is sealed.
Step 14: Stuff and Close
To begin closing the bottom of the dress form, loosely tape across the opening, leaving a hole large enough for your hand. When the entire bottom is covered except for the hole, stuff any remaining paper that will fit into the bottom and tape up the hole. Stand the dress form upright to be sure it sits evenly.
Step 15: Correcting Defects
In case you had a fidgety model or other mishap and ended up with an oddly shaped area, you can use your scraps that you saved as a sort of dress form putty. Simply take your scrap and fold or wad it up, depending on how large and deep of an area you're fixing. Stick the scrap onto a strip of duct tape and arrange it on the dress form in the area that needs to be filled. Cover the scrap with duct tape so that it blends in with the rest of the dress form.
Step 16: Alterations
If your form is too large or small, you'll need to perform a little cosmetic surgery. To make the form larger, cut two lines vertically down the part that needs to be widened (bust, waist or hip), lining them up with the center of each breast. Open each cut half as wide as the area needs to be altered and tape while holding open. (Example: If your waist is 30" and dress form is 29", open each cut 1/2", making the total widening 1")
If you need to take your form in, mark the waist on both sides in line with the center of the breast and draw a vertical pointed oval approximately 2-3 inches tall. Cut the ovals out of the form, pull the sides of the ovals together and tape. Repeat with the hips as necessary. To take in the bust, cut the ovals directly under the armpit of the dress form on each side. (see photos)
Measure your newly sized dress form and adjust again if necessary. If no further alterations are needed, smooth the areas you've cut down with a few strips of tape.