With each section of the Captain America ball chair project it has gotten more interesting as I have progressed as well as more time consuming. In the last post I had completed the skinning of the third section of the ball. In this post I will show you what I had to go through to construct the fourth section of the ball which has turned out to be one of the more difficult yet rewarding (so far) pieces of this big puzzle.
As in the first three sections of the ball portion of the project I started construction with a ring and the spacers needed to create the outer shape of this last section. This section is not a ring like the other sections but rather a dome that will be the center of the back of the ball chair.
The ring and spacers at this point were hot glued into place just like the first three sections. There is no additional ring that is added at this point but rather a dome shaped cap. In this photo you can see the circular two inch disk that I cut so that the cap could be shaped in the next process. I laid the cap on to the spacers at this point just to check the fit of the pink foam disk.
The dome is seventeen inches in diameter and is made using these simple templates that will help guide a hot wire when the foam is cut into shape.
I needed a simple way to hold the circular disk so I placed a one inch wooden down in the center of a eight inch square piece of 3/4 inch plywood. This will help hold the foam and be able to rotate it when I make several cuts with a hotwire bow and the templates.
In this photo you can see that I have screwed the two templates and the center mount to a plywood board. I then clamped this jig onto my work table so that it would not move when I wanted to make my cuts into the disk.
The foam disk was then placed on to the center dowel ready for the first cut.
In this photo you can see what is called a hotwire bow. The black box in the upper left corner of the photo is the power supply the feeds electricity through a wire that heats up and will cut the foam when it is run over the templates for the dome I needed.
After the first cut I got a nicely curved surface across the foam because of the templates.
After rotating the foam disk I made three or four more passes over the templates to get a nearly perfect dome shape. With a bit of sanding the disk will be ready for assembly onto the last section of the ball chair.
Here is the newly formed dome cap after I had carefully sanded it down as uniformly as I could by eye. This portion of the build did not have to be absolutely perfect but I try to make it as perfect as I can get it as it makes things easier as I go along.
After dismantling the template jig I used the center mounting plate with the wooden down in it to hold the dome assembly upside down on the work table so it would not rock around when I worked on it. This made it easier to glue the spacers of this section to the dome cap.
I used a hot glue gun and slowly aligned the curved spacers of this section so that they match as closely as I could to the dome cap. This is very time consuming as the hot glue needs to cool a bit before I could let loose of each piece as I moved forward in the assembly. The hole in the center of this piece did not matter as it would be covered up as I progressed further.
Once the framework of the dome had been completed I moved on to gluing on 1/4 inch foam strips over the top of the now upright assembly. I started with a cross pattern of three strips each direction. I thought this would work best so more marking, cutting, and hot gluing was the next step in the assembly.
From the first cross strips I then divided each empty quarter again with three more additional foam strips. This allowed me an easier way to keep the pattern going as well as forming the correct shape for the outer skin.
Nearly done at this point after two good days of just putting the outer skin on the done section. I did five hours worth assembly the first day and had to call it quits before my eyes and nerves would give out. As I said it is very time consuming work.
Here the dome section is finally completed. Even with this section of the ball chair only being glued up Styrofoam pieces it looks to be very strong. I would not doubt that I could stand on it without it breaking. Not that I would even take the chance with the hours I've put into it so far. The first three sections of the ball took me 25 hours to complete. This section alone took another 14 hours to assemble. Again what slowed me down on this section was all the fitting that needed to be done to get the skin on the dome correctly. This section alone has 120 pieces in it including the parts for the framework. I think my efforts make this section look pretty good at this point.
I had to take this shot simply because it is a great look. Like the other sections of the ball chair it will be a shame to have it covered up once the project is complete.
So here is the ball section of the chair as of this afternoon. I had to get into the shot just to give you a good idea of the scale of the ball section. It's a good start to this great project and I am looking forward to getting further along with it. The ball is 42 inches in diameter and in this photo the sections are stacked up with the opening for the chair face down on the table. There is a lot of work that needs to be done yet with these four sections of the ball to get them ready to be assembled and prepped for paint. But that is further down the line and is on my to do list for another day.
Enjoy the photos. I'll keep all of you up to date as I keep plugging along on this big fun project. Have a good day in your workshop as well.