First you need to cut the following pieces:
Main piece: (length of bolster +2cm s.a.) x (diameter x 3.14 + s.a. of **4cm** + zip allowance of 7cm)
2 end pieces: (diameter x 3.14 + 6cm) x (diameter/ 2 + hem allowance of 3cm + s.a.)
2 x little tabs for zip ends: about 4cm x 15cm
I make my piping cord's bias strips 5cm wide - just a nice easy width to cut on my cutting board with my rotary cutter, so when it is complete it has a seam allowance of 2cm. This will be on each end, so I need this ** seam allowance to be 4cm (2 x 2)
Piping cord covering fabric: strips cut on bias. See here and here how to make it.
Use an endless zip cut 10cm longer than one side of your bolster cushion.
Leave the 'head' of the zip on the extra 10cm so that it is not in the way of your needle as you sew.
Watch this silly little video I made to show you how to use endless zips.
Here is a great 3mm (teeth width) endless zip supplier online.
On the end of your zip opposite this extra tail of zip:
With your zipper foot on your machine, sew one little tab (folded under red arrow below) to one end of zip, like the black arrows show here:
Then zig zag one edge of your main piece (one of the ones that is the length of your bolster)
Place this zigzagged edge RST on the piece in the above photo with the selvage of main piece matching the zip selvage, like:
Stitch until about 10cm away from opposite end of main fabric. Then measure how long (after fold) your 1st tab was and add your second at the same measurement from opposite end. Use a pin to mark where you need to place folded edge of 2nd tab.
Then fold over the main piece of fabric to form a flap over your zip (to hide it)
Press in place & then stitch down:
Press in flap:
Stitch down flap with zipper foot:
At end, make a square ( as shown) to keep the flap secured:
Pin back this flap as far as possible:
So that when you add the other side of the main piece to your zip, you do not accidentally catch the flap in the stitches.
Make sure your main piece is cut exactly the right size now. Measure from stitch line on one side, to where stitch line will be on the other side. It should be EXACTLY the circumference of your bolster as you need a snug fit.
Circumference = Diameter x Pi
π = 3.14 (rounded off)
Image found on this site
My bolster is 14cm x 40cm
So my circumference = 43cm
This should be exactly right then:
If that is the case with yours, go ahead & join on the other side of the main piece (after zig zagging the edges) to the other side of the zip. Press.
If it is too big: cut off the extra
If it is too small: you measured incorrectly! Fancy a band of contrast? No, then you will need to make your seam on your zip really tiny if this will give you enough space. Or your inner will just be a little extra snug in your cover.
Pull your zip head through & snip off extra zip
Sew the flap at the one end down so that you have a smooth edge to add your piping & bolster end to.
Do my arrows make it clear? ;)
Add your piping cord to each end of your tube matching the selvage edge of your piping cord with the selvage of your bolster tube.
There is an alternative method to add in the zip, and that is using the method we used for the non piped scatter cushion.
If you use this method, I would recommend using double sided tape to hold the zip perfectly in place.
You can watch this video I made to remind you of this method.
Sorry the pictures are so tiny! Make it full screen & you will see okay. I did something wrong with the settings on Camtasia for this!
Use the method of finishing the piping cord used for piped, zipped scatter cushions.
Leave a tail BEFORE you start sewing on your piping
Open up the stitching of piping cord on tail you left
Snip off extra cord
Fold piping without cord in it under to form a neat edge
Match up end you are busy sewing down to cut off cord end & cut off cord you are busy sewing to match the cut end exactly
Stitch right through all layers to give a very neatly finished seam
Now, take each end piece & zig zag one long end of each piece
Then fold under a 3cm hem on other long end, press in place, stitch down close to selvedge edge folded under
Do this to both pieces
Fold in one short end & stitch down. Then start adding it to the piped edge, RST
When you get to other end, just keep on stitching so the ends overlap - not too much (3cm will do) - keeping very close to piping. Do not make the fold under as you see in the picture above, I went back & fixed that as it prevented the end pulling in nicely in the next step!
You now have this:
Take your strong thread & begin stitching in long stitches through the edge of your end piece which is free, right along the fold line, leaving a tail to your thread.
Pull thread in until the edges are gathered to the middle
Tie ends off well.
You will now make a covered button to cover the gap remaining.
Watch this for covered button & how simple it is!
Do the same on the other end.
Now add your button on one side with a very long upholstery needle.
Pull the needle through to the other end & add the 2nd button.
Pull as tight as you like it so that the buttons are recessed.
The down side to this... when you want to wash the cover you will need to remove the buttons & then replace them when you put the cover back on. There is no way I know around this!
Grab a cuppa and a good book, lay back & test out your new bolster
RST = Right Sides Together
s.a. = seam allowance