Tuesday, November 26, 2013

Big butt adjustment (BBA) - another round of Thurlow pants! (kind of a tutorial I guess)

I made a pair of Thurlow pants a little while ago somewhat successfully. I blogged about them here. They are not bad. Since that blog post I have added one more belt loop at the back and added buttons to the welt pockets. That made the fit a lot better.

Pocket button.

I have since then used them a lot. Almost every day, actually. But I am only 95 % satisfied. The rest of the 5 % is gnawing away at my brains. Oh, the pain of gnawing at brains!! ;-D
I'll show you:

Issues to be resolved.

I still need some more booty room and the angle where the legs hit the butt is not quite right. The new belt loop and the buttons solved parts of the fabric droop, but still left things to be desired. This gal ain't happy until she's happy if ya know whatta mean!!

Time for round 2!

Since I had modified the pattern quite a bit before sewing last time I decided to compare my pattern with the original pattern sheet. And I was really surprised that I actually made pants SMALLER THAN SIZE 0!!!!!!! - except for the butt. I have never worn a size 0 in my life. That sizing chart is bent if you ask me.

Modified size 6 = smaller than size 0!

Anyhow.  I have now decided to start from scratch, from a size 0, and then do what I will call a Big Butt Adjustment (BBA). I know some call it Full Butt Adjustment (FBA). But I think it sounds kinda gross (constipated much, anyone?) plus it can be confused with Full Bust Adjustment (FBA).

I will do it pretty much like shown by Coletterie here.

Note! The BBA is done only on the back pattern piece!!

#1 - Tracing a size 0. 

Marking the seam lines to make the changes within the "finished garment" and not in the seam allowance area. In this pattern 1,5 cm seam allowance is included.

Dotted lines mark seams.

 #2 - Marking the cutting lines. 

This isn't an exact science. The green pivot circle should be places a good inch below the dart point though (roughly where you think your butt cheek apex is) and the vertical green line right through the dart. All other pivot points (circles) are placed on the seam lines. I'd suggest the angle of the turquoise line should be determined by how far down on your thighs you feel the need for extra fabric. The read line is for adding length to the crotch line.

The great thing about adding butt room this way is that you don't change your side seams at all. That means that all the pattern pieces will still go together like a dream. Cheers to that!

Marking all the cutting lines and pivot points.

 #3 - Slash 'n' spread! 

Cut along all the lines STOPPING at the pivot circles!

Now, to get the right amount of spreading I compared my old pattern piece with the original patterns and found that my butt requires roughly a size 6. The difference in width between 0 and 6 is about 2 cm (less than 1 inch) so that is the amount I am spreading.

If you don't have an old pattern piece like me, you can try to measure the pattern across where your butt is at its biggest, double the measurement (minus seam allowances). Let's say that adds up to 40 cm on the pattern in the size you've chosen. If you now measure your ass in the same place with a tape measure, you may get, say, 46 cm. That is 6 cm more than the size of the pattern. Which means you need to add about 3 cm in the BBA (since we're doing half a butt on the pattern).

Comparing with the old pattern piece.

#4 - Tape in paper and redraw lines
When you're happy with the alignment above, tape in paper and redraw lines.

Before I cut the paper, I measured the pocket marking to 13 cm. I make sure now when I redraw the pocket marking that it is still 13cm. If you look closely below, you can see the old pocket line penciled in. The dart is redrawn by just following the old dart legs until they meet again (blue lines, not the green). They should now meet the pocket line, just like they did before.

New dart and pocket line in blue.

#5 - Verify the crotch curve.

When I compare my old pattern (which I had altered a bunch of times) I see that I need to deepen the crotch curve a good deal, thus making it more L shaped. I am marking this on my new pattern and then cut. 

Old pattern, on top, has a deeper curve than the new pattern.

BUT. I wasn't entirely happy with how my butt pushed the fabric down, remember! I suspect I have a low hanging butt (nice, eh). To find out how my crotch curve REALLY looks I got a tip from a friend to roll up some tin foil and then form it against your body (along the crotch line). 

Placing my pattern pieces together (overlapping the seam allowance and then adding my foil roll shows the truth: Yes, I have indeed a low hanging butt. And this is even after I did the above adjustment... 
The pattern pieces shouldn't follow the foil roll exactly, but the shape should be the same. See the difference in the angle (black lines) and the size of the yellow arrows?

I draw a new line that better reflects my body. Purple curved line below:

Finished pattern piece!!!

The daddy.

Just for fun I will now compare the finished pattern with the old one:
In this pattern we see the biggest difference is actually the crotch line and the size of the dart. Everything else is kind of the same around the butt. Remember I said I thought they were just too tight? I figure since I now started on a size 0, and the old front pattern pieces were actually a good deal smaller than 0, i will gain the extra room around the body by not altering the front pieces. This should make the side seams better positioned than last time too.

The real difference is when I compare the whole pattern piece!! Look at the angle of the legs!!! You know when you pin out fabric here and there, weird things can happen. Hopefully this will now take care of some of the drooping fabric behind the legs too.

Anyway, it just goes to show that it is easier to take a smaller size that fits most parts of you okay, and then add extra room where you need it, than going for a larger size and then pin out all the excess. THAT should be famous words, my friends. Just compare FBA. Same thing there. Am I right?

Now I "just" need to sew them up, and that will take me a couple of days. I'll let you know how it went. I will also go against my better judgement and skip doing a muslin. I need pants NOW and whatever saves me time... (famous last words).

So long!


  1. Amazing. Very through and easy to follow…I think! :) Thanks so much for going through all the trouble to document this. Now, it's my turn!

  2. This souns soo logical. And this is an answer to my latest sewing problems, too. I'll try to find out about the shape of my crotch, too!
    thank you!


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