I have just acquired 4 metres times 1.5 metres of ripstop nylon fabric also known as Spinnaker clothe. I also purchased 30metres of thick polyester thread, some attachment material (like Dacron tape) and one hundred pack of 1″ rings. (I only need 8 of these rings). The rings are the sort you use for curtains. I purchased all these items from Spotlight in Cairns for about $40.00.
I initially asked someone to create the jacket but was advised that it could not be done on a standard sewing machine; that an industrial sewing machine was required. I didn’t quite believe this and discovered that it can be done on a standard sewing machine. I made the decision to construct the jacket myself.
I was generously loaned a ‘new’ home sewing machine which I will use to construct the jacket for the high altitude balloon. For the last week after all the day chores have been done, I have been cutting sections off and familarising myself with the sewing machine and trying to do some seams.
After about a week of trying to perfect the stitches I realised I wasn’t going very well. The sewing machine couldn’t load the bobbin (so I did it manually), the thread was very thick and hard to thread, the material was crunching up and it looks liked the top thread was appearing in the bottom, i.e. incorrect tension. Purchasing a bobbin winder was $129 and a new sewing machine of the same caliber was about $250. So I decided to purchase my own sewing machine. This has been one of my better decisions. I haven’t looked back.
The jacket design I have been using is from Parallax Inc document which has a lot of good information on HAB designs. Because I am very new to sewing I have cut out pieces of paper and used a stapler to work out how to ‘construct’ the jacket. I’ve realised that making this jacket is a little more involved/complicated then I anticipated, so making a prototype out of paper/stapler helps me to visualize how it will all fit together. The document from Parallax Inc was a bit difficult to read and I did modify a few things, in particular the way the tube was constructed and the way the bottom was attached. I also suspect that I the top will be simplified. I do think that the people who designed the jacket may have made things more complicated than necessary. That is something I guess I’ll find out.
The opening for the cameras
We have two cameras and they need to have full access to the skies. We did this by cutting a square hole in the fabric and then using some Birch Bias Binding to strengthen this area and stop the fraying of the fabric. See the pictures below.
I detoured off the design in the lid in the Parallax document. The doc said to wrap some ripstop nylon around the lid and hand sew. This seemed awkward, so my next idea was to hot-glue the ripstop nylon on to the styrofoam. I tried this out on a piece of sample syrofoam and fabric. It worked well. I then decided even that was a little ‘over the top’. The whole aim was to try and keep the lid attached and to ensure the jacket is tight/firm and doesn’t cover holes. I got some Velcro with sticky side and stuck this on top of the syrofoam lid. Then I sewed the other Velcro material to the jacket. See image below.
There is the possibility that the velcro may come off the syrofoam at high altitudes dues to the evaporation of glues in the low air pressure environment. This I guess I will find out, should the HAB be recovered. One can be said, is that it is a lot simpler then the original design.
I must also thank my neighbour for his suggestions with the Velcro-to-Syrofoam suggestion.
I must not forget to mention the help my eldest son Jeremy is provided in the construction of the HAB. He provided some fairly frank advice regarding the sewing of another seam to protect the bottom edge of the side tube. I accepted this advice. Thank-you Jeremy.