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Making a Mock-up for the Tabula Rasa Jacket

This week we are going to review the basics for constructing and fitting a Tabula Rasa Jacket (TRJ) mock-up. If you are new to the TRJ, we are delighted you have joined the Fit for Art family!

Fitting prescription and size chart

If you saw us at an expo and were sized in our fitting shells, you will already have your “prescription,” telling you which size to start with as well as which front and side panel patterns to choose.  If we prescribed a few pattern modifications to make before you cut your fabric, remember to visit Common Fitting Adjustments for the Tabula Rasa Jacket for illustrated help with making those pattern adjustments, and Video Tutorials for a step-by-step demo of the six most common fitting adjustments.

Common Fitting Adjustments for the TRJ

If we haven’t sized you in person, start with the size chart on the back of the instruction book and your bust and hip measurements. Then consult our directions in section A.1 to help you choose between the AB and CD front and the straight and flared side panel. Because of these fitting options, women who have been sizing up in ready-to-wear to accommodate their bust or hips often fit in a smaller size than they expect.

Cut out each pattern piece in your size and then cut your mock-up out of a heavy muslin or similar light-colored fabric. Layouts, which are suited to directional fabric, are suggested in the instruction book. For a mock-up, however, you can often conserve fabric by cutting some pieces on the cross-grain or by flipping them head to toe. I was working with just a 48” length of leftover Starter Kit muslin for this sample, so I cut the sleeve on the cross-grain.

Mock-up layout

Before removing the tissue patterns, transfer all markings and prepare to draw each horizontal balance line (HBL) and grainline onto your mock-up. We suggest marking both ends of every HBL and grainline with a small clip or dot with marker. Remove the paper; use a ruler and permanent marker to complete each line on the right side of every piece.  Here I am demonstrating several of these steps!

Because the construction order of the square armhole TRJ is a little unusual, let’s review a few important steps. In Step 6, attach the prepared sleeve to the side panel, right sides together, matching the sleeve’s underarm seam to the square mark on the side panel. Here you can see them pinned together and then pressed open after being sewn. Note that the double notch on the sleeve lines up with the double notch of the side panel; while this is not confusing in fabric with an obvious right and wrong side, in muslin or other solids a mismatch here can trip you up later in the construction.

Sleeve/side unit pinned to back

In Step 7, insert that sleeve/side panel unit into the body of the jacket. I find it helpful to lay the jacket body on a table with the right side facing up, wrong side against the table. Turn the sleeve/side units right side out and lay the first sleeve/side on the jacket’s back, matching the double notches and the dot to the sleeve/side seam; pin this side in from the notches to hem.

Next, pull the jacket’s front over and lay it right side against the sleeve/side unit, lining up the single notches and the dart to the sleeve/side seam. Pin this from notches to hem. Match and pin the shoulder seam to the shoulder dot, then ease the rest of the sleeve head in, pinning out toward the front and back notches. Pull the gather threads slightly as needed to fit the sleeve head to the front or back, keeping in mind that this sleeve head requires very little gathering.

Voila! Now you are ready to sew this side seam from one hem, up around the sleeve head, and down to the other hem.  (I find it easiest to sew with the sleeve/side facing up and the front/back against the feed dogs.) Repeat pinning and sewing for the other side. Finally, press the side seam allowances toward the sleeve/side units and try your mock-up on.

Stand in front of a full-length mirror (and use a second mirror to look at the back if possible!) to assess the fit. Ideally the HBLs will be parallel to the ground and grainlines will be perpendicular to the ground. Any deviations from this grid are your clues to where fitting adjustments will benefit you. Its time to consult the Common Fitting Adjustments for the Tabula Rasa Jacket for help with identifying and making those adjustments and the Video Tutorials for demos of the pattern work.

To the extent possible, try out the changes you think you need by basting them into your mock-up. Some adjustments, such as adding more room at the bust or fitting a rounded back, may require you to cut out and insert a new piece. Its best to make one change at a time, starting with the simplest; if you make several changes at once, it can be difficult to tell whether each one improved the fit or not, or even created a new problem. When you are finished adjusting the mock-up, be sure to go back and record the same adjustments on all of the affected pattern pieces, noting the date for future reference.

If you get stuck, contact us by email with your questions and we’ll do our best to help you sew successfully.  If this feels like a lot of work right now, just remember that once you’ve gotten your mock-up to fit, you can make a full wardrobe of well-fitting jackets and tops with this pattern and the TRJ Variations.

Happy Sewing, Carrie

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