6th November 2010: Tricorder Bag 6 That was most of the work which needed done before the bag was sewn together and lined. I sewed the final side seam, and turned the bag the right way out. Turning it was not easy - probably the most sensible approach would be to insert interfacing between the lining and outer pieces after having turned the bag the right way out. I did intend to sew the base on before turning it, but the interfacing made it so stiff, it was easier to finish up the base by hand from the outside.

The flap had its silver trim sewn on and I also put in studs on the back. These bits could have been done earlier, but I thought it would be safer to check the exact positioning of these details once the bag was sewn together.

Next up was the lining. I sewed it all together like the outer bag, but unlike the leatherette, there were no problems with turning the lining the right way out! To attach the lining to the outer bag, I first sewed it into the flap section of the bag only. This was done by placing both pieces right sides together and sewing around the three edges of the flap, clipping the corners, and turning it the right way out. I found the flap needed pressed to get the lined edges neat, so left it under a heavy book for a day, which did the trick! I also put in the other half of the magnetic clasp at this stage after the pressing.

That left the remainder of the lining to finish up: the raw edges at the tops of the side pieces and the front piece. I folded the lining under and stitched in the ditch next to the piping on the sides and straight across the front panel, catching the leatherette and lining.

There’s probably a more sensible way to line and construct bags, but this worked out ok for my first attempt at bag-making!

5th November 2010: Tricorder Bag 5 I could then start sewing the bag pieces together, stopping sewing a half inch before the bottom and top of each side seam to leave seam allowance for attaching the base and lining later.

I finished up a few things while it was all still flat, inserting one half of the magnetic clasp and sewing the shoulder strap to the side pieces. I didn’t want to try turning a thin strap, so made it by folding a length of the leatherette in half, then tucking the edges in and topstitching it all. I put in some decorative studs to mimic screws at the on the sides where the straps are.

5th November 2010: Tricorder Bag 4 The side pieces had piping applied right round their edges. I sewed one length of piping right round each side piece of the bag, clipping the seam allowance at the corners. The join where the ends meet inevitably has a little bulk to it, so I made sure they ended up at the back and at a corner.

How to make and attach piping : http://sewing.about.com/od/techniques/ss/cordingpiping.htm
As leatherette isn’t woven, there’s no need to cut bias strips. I suppose a stretch pvc or metallic lycra would work well in place of non-stretch leatherette.

5th November 2010: Tricorder Bag 3 I then started work on the front panel with its pocket. The raised shapes were cut out and topstitched down over a small piece of wadding to pad them out a little. There’s only so much that can be done to imitate the moulding when working with fabric, but this was an easy element to do. I also sewed down pieces of silver leatherette for the handle shapes .

When the front pocket piece was done, I sewed its lining to it right sides together along the top edge, topstitched along the top, then attached it to the rest of the front panel by sewing along the sides and bottom edge.

5th November 2010: Tricorder Bag 2 With the leatherette, interfacing and lining cut out, I first attached the interfacing to each leatherette piece by machine basting around the edges. The photo shows all the exterior pieces.

5th November 2010: Tricorder Bag 1 I came across a couple of people online who’d made these, and thought it would be a fun prop/useful bag for conventions. I looked at screenshots for references and startrekpropauthority.com was great for close-up photos of the actual props

To start with, I figured out the approximate size and experimented with a paper mock-up until I thought I had the right dimensions and a plan for sewing it together which would work. Although I’d settled on measurements for all the main pieces, the designs for the front were just cut with some trial and error using rough templates to help. I found it helpful to fold my templates in half and cut out the fabric pieces on a fold to get them symmetrical.

I used:
- black leatherette for the majority of the exterior (just like the originals!)
- silver leatherette for the base (I don’t know why I care about accuracy that much) and it was also used for the piping and decoration. Turned out to be a good plan since being able to snip designs out of a non-fraying fabric was convenient.
- black and silver thread. The silver was machine embroidery thread I already had, but grey would be fine too.
- heavy sew-in interfacing (same as used for my dress collar) for backing each leatherette piece as well as on some areas of the lining. I chose to interface the base of the lining and the flap, but that's not essential.
- black gabardine for the lining, because I had it spare. Lots of other fabrics would work here.
- a magnetic snap for the closure
- piping cord
- wadding (batting) for padding out the designs on the front.
- four silver studs to mimic screws

Leatherette is also called pleather - it’s a leather-look pvc. Other fabrics could work for this bag, but ideally you’d want something non-fraying to create the front designs the way I did. Note that leatherette requires a particular approach when sewing. For example, when topstitching , you’ll need a Teflon foot or to use tearaway paper/talcum powder/some other technique of your choice. All pin/needle marks will show, so care is needed. I used sew-in interfacing since ironing risks the fabric melting, and used a heavy book when pressing was required.