Solar Balloon Part 3-Time to Melt stuff
This week me and Andy wanted to start construction of a new solar balloon using the new numbers that we had run in the last solar balloon post. one of the things that we bost agreed was the downfall of the first solar balloon was the weight added by all the tape used in construction and patching or holes. Because of this, we wanted to see if we could find a new and lighter way to seal everything together. We wanted to see if we could get a method of fusing the plastic together to work. The idea is that we would use heat to make both layers of plastic melt slightly so when they cooled back down they would be melted together and therefore fused without adding any of the weight that would come from using tape.
Because one of the major design goals for this balloon is to keep the cost at a minimum, we have decided to build our balloon, at least for now, out of cheap plastic trash bags. One of the advantages of this is they have a very low melting temperature making fusing easier. The next thing we needed was a heat source. We decided to try a cheap iron like the one that can be bought at Walmart for ironing your clothes. we went with this because it has multiple heat settings that will help us to while in on the ideal heat for fusing but not melting the plastic.
the next thing that we needed to address was the rate at which the heat was being transferred to the plastic. Even at the lowest setting, the iron can easily melt straight through the plastic if you are not careful. We received a tip that placing a layer of parchment paper between the plastic and the iron will help to slow the heat transfer rate to a degree that it becomes more manageable.
With all this together, all that was left was to find the exact temperature setting for our iron. If you are going to be duplicating this technique for one of your own projects then keep in mind that not only will your iron be behaving differently but also the heat required to melt different plastics is drastically different so you will need to find your own heat settings for your situation. what worked for us was to turn the heat all the way up then take one or two quick passes over where you want to fuse the plastic together. Any longer and the plastic ends up melting holes in itself and any colder and the two layers don’t actually fuse. done right and you end up with a lightweight bond with few to no holes and yet just as tough if not tougher then the original plastic.
I hope this post was interesting and helpful to you. We certainly learned a lot about it and super excited to start building the mid-scale balloon very soon. until then, good luck with your own projects and Happy Tinkering!