Just recently I bumped into a huge weakness of the mock-up: you do not wear them all day.

If you sew garments, at some point or another you will come across the advice to always make a mock-up. Also called a muslin, calico, or toile, it’s a test version of the garment that lets you fine tune things like fit. I’ve been told that for the best results you should make it out of your fashion fabric or something as close to your fashion fabric as you can get, but let’s be real—the vast majority of mock-ups are made from cheap fabric. Especially when I know I’m going to go through two or three of them.

This is usually the case when I’m making something fitted or semi-fitted.  The size guide on the back of the pattern envelope is usually less than ideal (some lines are better than others, to be fair), and going by your commercial size is a gamble, so making at least one mock-up is essential.

But no matter how good it is, there are some things the mock-up just isn’t going to tell you.

What I said earlier about making the mock-up in something close to your fashion fabric is because things like body and drape affect how the garment fits.  Muslin pants are not going to fit the same as denim nor is a muslin shirt going to drape the same as rayon or silk.  But you can usually get enough to move forward.

However.  I don’t think the type of fabric was the culprit in my most recent sewing snafu.  Even if I had made the mock-up in the fashion fabric—rayon, in this case—I still wouldn’t have done more than fasten it up, twist and bend and take a few deep breaths to make sure it wasn’t pinching or gaping or doing anything strange, call it good then take it off to start finalizing the pattern.

The pattern I was working with is Burda 7785—a strapless sheath dress.  Now this is where I bumped into one of the gaps in my sewing—and clothing—experience.  I know enough about strapless garments to know that they have to be very well fitted around the torso to have a chance of staying up.  For this dress, because of the split in the bust, that means around the ribcage and waist.  And that’s what I did;  I fitted it so close that I have trouble zipping it up.  And for the first few hours it was fine.  My constant tugging at it was mostly paranoia born of not being used to wearing that sort of thing.

By the end of the day I was genuinely having to tug it back into place. On day two I had to actively hold it up.  The only reason it stayed a dress and didn’t become a really awkward skirt is because I have awesome friends who clued me in on (and brought) toupee tape.

In case you haven’t guessed, the thing I hadn’t taken into account is that fabric relaxes.  I know this in other contexts—it’s an important consideration in corsetry—but my limited experience with strapless garments meant I didn’t put two-and-two together.  I also trusted the pattern, even when I had a niggling feeling that I shouldn’t.

This is really where the limits of my on-the-fly, self-taught sewing skills smacked me in the face.  I knew enough to to have some uneasy suspicions that things weren’t adding up, but not enough to have confidence in those suspicions.  Commercial patterns are not infallible, and I know this, but I still trusted that this pattern at least sort of knew what it was doing.

The only boning the dress calls for is in that split in the bodice, to keep it from flopping over.  Likewise the bodice is the only place where it calls for interfacing.  That’s fine for the bodice, but the greatest strain on the dress is just below that, in the underbust and torso.  The fact that there was no support or interfacing here should have been a red flag.  But I went ahead and trusted the pattern.  Partly because I was—once again—sewing on a deadline, but mostly because I just wasn’t confident enough to do otherwise.

I definitely know better now.  I’ll go into the specific fixes in the next post because this one is getting overlong, but the long and short of it that if the garment is going to remain in place, the support needs to remain in place—or rather it needs to be there in the first place—and patterns are not always to be trusted.

For the record, I don’t think the fault is in my choice of fabric.  Granted the example dress is made of a heavier fabric, but denim is one of the worst offenders for relaxing.  Think of the difference between putting on a pair of jeans fresh out of the wash versus that same pair on the second day.  That model wouldn’t fair any better than I did.