Work on the backpack has been slow because I have not given it any attention. Probably because I'm a little bored with it because its just a box. But I have most of the pieces cut. I just need to sand the main box and then add the rings around it. the most difficult part of the pack will be how the tank attaches.
Sintra, the plastic I use for the box, reacts to baking and boiling, during which it becomes soft. Once its cools it retains the shape it was left in. Thats what I plan on using for the tank ring but the slight slope of the tanks sides make it a little harder than just using a long enough piece of sintra. Due to the shape change the top portion of the band will be longer than the bottom, so I will have to counteract that by adding a slight ark to the cut out piece. Which will require a lot of trial and error.
The gun I have devoted more time too and it is slowly coming together. Its mostly sanding thats left before painting. This time I just flat out ignored PVC tubing. If I am to be true to the design, I need a lot of odd sized tubing and there are few to little options in PVC. With the original medic gun and backpack I made concessions to the design so I could use PVC for certain parts, which in the end I think made me unhappy with the outcome. I also think that PVC is hard to shape and cut properly if you do not have the perfect tool for it. So as of now the gun is 100% MDF which is working wonderfully. I also plan on putting LEDs inside for a little razzle dazzle.
To get all the rounded and canister shaped parts required for the gun I cut a bunch of rings to the right size and glued them together. The result is sturdy and responds extremely well to sanding if thought out properly. Example:
This is the muzzle of the gun. From the full gun image several steps above, you may notice it has two tongues coming out of the top and bottom. To shape it into a smooth rounded shape I would have to get rid of the rings so I can get sandpaper all around it, then add them on after. Simply cutting the tongues out with a curved bottom so I could directly glue them on would work. But there would be no guarantee they will sit right and I would most likely have to use putty to fill gaps.
The muzzle started off as 4 pieces. Two circles that make the front and back part of the muzzle, and two circles with tongues attached. Before anything else I glued the tongued parts together then cut the tongue sections off. I then glues the other circles on and then sanded it to a smooth surface. The tongues now fit perfectly on because I'm simply refitting the same cut surfaces back together, like a puzzle.
I'm considering using the same ringed MDF process for the backpack cannister. The problem with the current one is that its fragile and dents easily. It is made out of shaped foam and coated with wood putty. I made the foam core too close to spec so the wood putty is only a thin shell. If I made it out of a bunch of MDF rings I would get the strength, and if its hollow I could save on weight. But even that may be too heavy.