The dust is still flying here at the workshop with all the work that I am still doing on the Captain America ball chair project. I am slowly starting to see the end of the tunnel with this project as parts are finally starting to be completed and test fitted to other parts. A good sign to be sure.
In this post I wanted to show you this progress with the work that I just completed on the mounting of the rings of the chair to each other. The first sections that I decided to tackle was the dome section (the blue section with the star shown above) and the first ring next to it (the red one) in the ball.
This is an image of the inside of the dome just after I completed it's construction.
In this view you can see all of the modifications that needed to be made to the assembly to get it ready for the mounts that are used to hold this to the mating ring. Lots of measuring and trimming needed to be done and I'll try to explain as I go here why and how this was done.
The cavities in the outer ring will be where the hard mounts are bonded into the ring to mount it to the mating ring. The missing ribs and center sections in the assembly have been removed to allow the wedge shaped center sections of the chair to be mounted in the final assembly. I covered these wedge shaped sections in an earlier post so you'll have to back track a bit to get the info about these parts for the project if your now lost and have not read about them.
To make the hard mounts for the dome section I first started with a strip of wood one inch square and roughly two foot long. This piece shown above will be used to make nine of these mounts. I originally thought that would be enough only to find out that it was simpler just to make it an even dozen so another strip needed to be prepared later on.
In the strip of wood I marked out cutting lines every two inches and then drilled a half inch hole at the center of each of these sections. I then wrapped the bottom side of the strip of wood with painters tape. This will hold the epoxy resin from leaking out when I want to install the threaded rod inserts as shown in the photo above. The tape on the threaded rod was needed to also keep the epoxy resin from getting into the center of the insert and messing up the threads.
A drop of fiber glass resin was then poured into each of the holes and a thread rod insert was placed into the hole and left to cure overnight.
Once I had all of the threaded rod inserts bonded into the wooden strip I simply cut the strip up at the marked lines and finished adding additional epoxy where needed to securely lock the threaded rods into each block. I let this again cure overnight and was then ready to install then into the cavities that I had cut out of the dome section of the chair.
The foam from these cavities were removed using a hot knife tool the heats up either a steel rod or wire loop to melt the foam away from the dome to form the cavities. I then used a sharp knife to scrape any excess foam off of the inner lip of the dome cavities. Once this was done I slid a hard mount into each cavity in the dome, marked where the threaded rod would need a hole for the mounting bolt, drilled the hole and I was ready to go. I then remounted the hard mount and bonded it in with a fiberglass resin and micro-balloon mixture to secure it in place.
Once the block had been puttied into place I took the mating 1/4" plywood mounting plate that will be installed into the mating ring assembly and attached it to the mounting block using a one inch long 1/4-20 bolt and washer. This I then tightened down to securely compress the mounting block to the dome cavity lip and align the part properly so that it will be a perfect fit with the it's mating part in the assembly.
This process was repeated twelve times in the assembly as shown in the photo above. This will make a very strong and simple joint when it comes time for all of the rings to be put together for the chair.
After the mounting parts had been left overnight to cure in place I removed the bolts, washer and plywood mating plate and I was left with a perfect hard mount that will work every time that I need to put the assemblies together or take them apart.
The next step in the process I then set the dome on top of the base that will be used for the chair. On top of the dome I aligned the first ring in the assembly so that I could mark it for similar modifications that will need to be made to it that I had done on the dome section of the chair.
You can see in the photo above the ribs that will need to be removed from the first ring so that it will match up with the dome section of the chair.
I marked out where the mating ring needs to be modified using a Sharpie pen on the foam. Along with these marks I put centering marks around the inner rings of the two assemblies so that once I remove these pieces from each other I will be able to align them correctly again once the modifications have been made to the first ring assembly. This I will cover in the next posting hopefully but I wanted to get this much info out to everyone following along so far.
So as I said earlier the project is slowly starting to take shape and I can see a little light at the end of the tunnel. Total time on the project now stands at 150.5 hours. The encouraging thing about the project is that Spring is starting to show up here in the Midwest just a bit and with it warmer weather. This means that by the time I am ready to start priming and painting I will be able to take this project outside and keep some of the dust, dirt and smell out of the shop (and my house). So things are looking up for sure.
Just one more quick note about this project. The photo above is the little test mold that I just completed yesterday as well. It has not been a difficult task to create but will be a great learning tool as I will make my first molded part from it. The mold has been completely fiber-glassed, painted with primer, and waxed with ten coats of mold release wax. Again not a hard task but a crucial one as I keep my fingers crossed that it will work the way I have planned so that when I make the inner wedge pieces for the ball chair interior using the larger mold for them I will not have any ugly surprises along the way. It's a learning process and will be worth it if I can get it all to fall into place. Keep your fingers crossed for me on this part of the project. I know mine are.