Wednesday, April 13, 2016

Completions, Near Completions, and Modifications........ Capt. America Ball Chair Project Pt. 16

This past week has been just a bit crazy with some major ups and downs with this project.  I had completed making all of the wedge pieces for the inside of the Captain America ball chair project only to find out that I could not get the pieces to fit into the chair!  Then panic sunk in.  Fearing that I had messed up hugely on my mold for the wedge shaped pieces and that I would have to start over.  The idea of having to modify the mold and scrap what I had already created did not sound like a good thing to contend with.  I spent an entire day scratching my head to figure out how far I was off with the mold and how to correct the problem to keep the project on track.  I narrowed it down to an error in the mold being 3/8th's of an inch to large all the way around.  That was the first error.  Then after more calculations I found that no matter what the wedge pieces would have never fit even if I had gotten the mold made exactly the way it needed to be in the first place.  Here's why.

This is a simple drawing to illustrate what had happened.  The ball chair has six inner pieces to the interior.  All of them are wedge pieces like a pie with a flange running around the outer perimeter. Just like a pie.

In this drawing I removed the inner lines that make up these wedge pieces to illustrate things even more simply.  The above image now is a ring that is split up into six equal parts.  Just like the pie shaped pieces.

Now comes the problem.  In order for the inner sections of the chair to be assembled they need to be installed from the outer surface and moved inward.  If you go the opposite direction the wedge or circular piece simply cannot be inserted into the ring or the pie shape as shown above.  In the ball chair the inner wedge pieces need to be install in a way that they will be inserted into the opening of the chair and then moved outward and into their correct position.  This is simply not possible without rethinking the problem and coming up with a new solution.  So I spent a day redesigning the inner wedge pieces so they could be assembled form the inside and move outward.

To correct the problem and not have to remake six new wedge shaped pieces I shortened three of the wedges so that they could easily be installed into the ball chair.  This was an easy task and I solved half of the problem. Next I took the last three wedge pieces and salvaged what I could from them to remake the outer flanges tip inward as shown in the image above.  With these changes I am now able to install the wedges from the inside the chair and move then to the correct outward position.

Here the first three of six wedges have been installed into the chair.  I could start breathing again at this point.

In the images above are the three wedge pieces that needed to be modified greatly to get all pieces of this portion of the puzzle to work out correctly.  I am thankful that I have worked with composite construction as long as I have to solve the issues that have come up with this portion of the build.  Whew!  The wedge pieces at this point still need a bit of tweaking to get the clearances that I want for all the parts to be assembled without further issues. But at least now I can see that I will be able to get all the parts to assemble into the inner section of the chair. 
  It's just a matter of doing some sanding and filling voids to get the pieces the way I want before I can lay fiber glass over the exposed Styrofoam and then remove the foam to be able to mount the last three pieces.   A learning process to be sure.  The big plus in all of this is that now I know how to make a mold and duplicate parts.  So it is not a loss at all.  Just a huge learning session.

Moving forward in another direction on the project I turned to the housing for the amplifier for the sound system for the chair.  The top photo above is the housing already in shape formed with several layers of Styrofoam.  The second photo is the same foam shape with the 3D printed amp mounting plate already fiber glassed onto the foam and prepped with the first coat of primer.  The Styrofoam is still in the hosing at this point.  The third photo show the backside of the housing or should I say the underside once it is mounted into the ball chair.

This next progression of photos shows the steps that I took to remove all of the Styrofoam out of the housing leaving me with only the fiber glass shell left over.  I cleaned the foam out with a hot wire loop tool that cut the foam out like scooping up ice cream out of a container.  Very quick and easy.  Once I had gotten the major portion of the Styrofoam out of the housing I was left with what you see in the third photo from the top.  At this point I simply took a pocket knife and scraped the inner surface of the housing and removed even more of the remaining Styrofoam.  With a little sand paper and ten minutes of time I ended up with the nice clean housing that you see in the last photo.

After the cleanup of the housing was completed I did some sanding on the exterior and drilled the required holes to mount the amplifier inside and the Captain America badge on the outside.  The orange piece in the photos above is the housing for the amplifier and this slid in nicely.  I drilled the mounting holes for the housing so that it can be mounted onto one of the wedge pieces inside the chair. 
  In the third photo from the top you can just see the port for iPod jack on the right side of the housing.  The cable for this port is hanging down just below the amplifier housing.  It took me a little bit to figure out where to drill the hole for this port and still be able to connect everything up inside the housing without some kind of interference.  It all looks good at this point.

I dismantled all the installed parts that were on the amp housing, wet sanded it once again and gave it another coat of primer.  The housing is very close to being ready now for paint.   Ever closer to finishing this portion of the project.

Lastly with this post I wanted to show off the completed switch assembly that will be in the ball chair to control the lights and the air ventilation system.  The panel turned out very well and will be a nice detail that will look good in the chair.  The first switch on the left controls one light and has one dot above it.  The second switch will control two lights and lastly the third switch is for the ventilation fans to be turned on.  Other than the switches this panel and the icons were 3D printed and then sanded smooth and painted separately.  So now it's just a matter of installing it into the chair after the wiring has been set up. 
  So that's about it for this week.  I can let the dust settle for a couple days while I wait for epoxied parts to cure.  I'm happy that progress is still being made and I'm able to work out the problems that have shown up.  Just have to keep plugging along.  With that in mind the weather now is looking better and better each day so I should be able to get at the outer sections of the ball chair to get them sanded, primed and readied for paint outside.   Works for me!  Have a good day in your shop.


  1. I regularly read your blog, keep up the good work! Thought you might this link to an alternate version of your chair...

    1. Thanks for kind words about my projects.... makes my day. Also thanks for the info about the 737-cowling chair. I'll have to repost it here on the blog. I'm sure more of my readers will like to see it as well.