Things You'll Need
Old lab coat or shirt
Large paper bags
Create a lab coat pattern using an old lab coat or men's dress shirt. With modest sewing skills and a basic understanding of sewing patterns, creating a lab coat pattern is as simple as tracing the necessary pieces. A lab coat pattern provides the opportunity to sew your own unique lab coats for use at work, school or as smocks for hobbies. If using a commercial pattern, cutting the lab coat pattern pieces requires only a pair of scissors.
Place the shirt on a clean, flat work surface with the buttons and button holes lined up and the sleeves smooth at the sides. You don't have to button the buttons--the picture is for reference. Take a picture of the lab coat or old dress shirt.
Separate the seams of the lab coat or shirt using the seam ripper. Pull the fabric taut on both sides of the seam, insert the seam ripper and cut the thread holding the coat together. As you separate the sleeves, back and front sides of the coat, set them down in order so that you know how they went together. Open the sleeves along their seam and remove the cuffs if they're separate pieces. You don't need to cut the seams holding the collar together, but separate the collar from the rest of the lab coat.
Take additional photos of the lab coat pieces for reference. You will label the pattern pieces, but photos will serve as a memory refresher when it comes to using the pattern to make lab coats.
Open the paper bags along the seam that's centered on one side of each bag and runs along the bottom. The bottom never opens neatly; just tear or cut it as neatly as you can and don't worry about ragged edges.
Lay one lab coat or shirt piece at a time on the paper bags. You may need to tape two or three bags together to get the right size for your pattern pieces. If necessary, use the measuring tape to continue pattern lines for extra length or to adjust size.
Trace each lab coat or shirt piece onto the flattened paper bags. Write which piece each pattern tracing is on the traced pieces so that you can easily identify them later.
Cut out the traced pieces, leaving 1/2 inch on all sides for seam allowance. Match the cutout pattern pieces with the separated shirt pieces and take additional pictures for reference, if desired.
For the collar and cuffs, if they're separated, trace the basic shape of the pieces. When cutting the pattern piece, leave 1/4-inch seam allowance on the top and side edges but leave 1 1/2-inch seam allowance on the bottom where the collar (and cuffs) attach to the shirt. Write on the pattern piece for the collar, "Cut two." You will need to cut two pieces for the collar (four for cuffs) and attach fusible interfacing to one or both sides of the collar (and cuffs) for support and shape.
If using an old men's dress shirt for the lab coat pattern, when tracing the back and front pieces onto the paper bags, use the measuring tape to extend the bottom length for a long lab coat.
If using a commercial pattern, spread the paper pattern sheets out flat, locate the lab coat pattern pieces you need, and carefully cut out each piece.