This instructable will guide you through the steps of designing and sewing your own pulk bag. Because everyone will have different requirements for their own bag, these steps describe the design processes and techniques needed to make a pulk bag.
*** These steps can also be applied to other sewing projects of similar difficulty and complexity such as sewing a regular duffel bag, or a backpack. Even if you are not interested in making a pulk, I made a list of the main things that I learned during this project and included that at the end.
Step 1: Get a Sled
Some sleds come with holes pre-drilled into the side walls. If your sled doesn't have any holes pre-drilled, you can drill some yourself pretty easily. It's helpful to string some rope through these holes for spots to tie down your gear to. You can also fasten some hooks into the holes as shown in the picture.
Step 2: Planning and Drawing Your Pulk Bag
Once you have the overall dimensions of the bag, start planning out how you are going to sew each portion. It helps (if not completely necessary) to break the bag up into several independent sections that you can sew together at the end. Determining how you will sew each portion before you actually sew anything is crucial.
!!! Don't forget to add extra dimensions for the sewing tolerance! Sewing two pieces of fabric together reduces the size of the combined piece because you have to mate them!
The following few steps will go into more detail about specific methods and techniques that I used to design my pulk bag.
Step 3: Disclaimer!
Step 4: Materials
Picking a good thread is also crucial. Nylon thread works much better than a polyester thread for this type of project.
Use all the pins you've got! Pinning your creation in place is a must in order for it to turn out as planned. When in doubt, add more pins! If you pin in a direction perpendicular to the direction you want to sew, you can leave the pins in place and just run right over them with the sewing machine. This is a huge time saver and guarantees that your positioning is where you want it to be.
You may be fighting the sewing machine a lot during this project. I spent a good deal of time positioning and forcing my pulk bag in a way that I would be able to sew into corners and sew it all together. That being said, I didn't have a great machine to sew with and I didn't have any special sewing "feet". After I used my bag for a trip, I brought it home and did some repairs on my parent's sewing machine and I couldn't believe how much easier the sewing was. If your machine is near the end of it's life, ask to borrow a friend's machine for this project.
Step 5: Securing the Bag to the Sled
The motivation for creating my pulk bag was to come up with a way to secure the bag to the sled while still allowing access to the zipper and the inner contents of the bag. Your decision on how to secure the bag to the sled may impact the design of your bag so it's important to determine this before you start sewing. It is not uncommon though, to simply use bungees stretched over the sled which requires no interaction with the pulk bag at all.
Step 6: Sewing the Base
I made the base using one single piece of fabric folded onto itself to create square corners. I wanted the bottom to have a defined edge(see picture)(*1) that ran along the side of the sled so I folded the fabric on itself and ran along the entire length of the base on either side making a strip of fabric the width of my sled. Then I made some triangle folds at either end to create a box-like structure. A plethora of pins held the ensemble together until it was sewn in place.
Step 7: Sewing the Top (and Zippers)
Step 8: Sewing the End Caps
The rear end cap was not too difficult because I lined up the top and the base sections. However, in my design, the top piece was shorter in length than the base so that caused some trouble at the front end.
The base was square, but the top section formed a trapezoid that was shorter than the base so I needed to make a front end cap piece that matched the square base and the top trapezoid at an angle. I had to use a lot of trigonometry to determine how big and at what angles to cut this piece. Sewing this piece was a nightmare as well because it all had to be done inside out!
I also was not quite sure as to how to make the bag close completely and prevent snow from reaching inside. I purposely did not cut the zippers (they were longer than the top section) and that allowed me to make a separate piece to overlap the end cap. Sewing on a piece of Velcro to the overlap and the end cap allowed the bag to zip completely closed and prevented any snow from getting inside.
Step 9: Putting It All Together
Step 10: Go Winter Camping! (Conclusions)
If you're not the winter camping type, here's a general list of the main things that I learned during this project that you can apply to other sewing projects. . .
1) Safety first! The sewing needle WILL go right through your finger.
2) The quality of the sewing machine and thread you use make a huge difference.
3) Pins, although enemies of your fingers, are the fabric's best friend.
4) Be generous when cutting your material and allowing for the stitch tolerance. Dimensions have a way of shrinking after everything is sewn together.
5) A good, detailed plan in the beginning will prevent a lot of frustration and re-design later on for large projects like this.
6) Plan to make a second one because you will learn so much on the first run that your second attempt will be 3X better.
7) Putting together a good instructable takes a lot more time than I initially thought. More updates to follow!