Saturday, March 19, 2016

Captain America Ball Chair Pt. 14..... The Wedge Mold Making Parts!

I've been making great strides in this project this week with the first three wedge shaped parts for the ball chair coming out of the mold.  I wanted to get this post out so I do not have a huge posting with delaying any further. So let's get to it.

This is the finished mold for the inner wedge pieces that will make up the interior for the ball chair. At this point the mold has been sanded several times and then sprayed with primer and then wet sanded with 600 grit sand paper several more times so the surface is good and smooth.

Next I applied ten coats of mold release wax.  This stuff is very much like automotive paste wax as it is applied the same way.  Wax on.... wax off.  You know the drill.  Already you can see a much nicer finish to the mold.

Finally I put on two coats of PVA mold release.  Gives the mold a near perfect finish.  The photo above is what the mold looks like after the PVA has dried.  Nice and shiny.

Now this was the moment of truth as far as my fiberglassing skills were concerned.  I laid down the first layer of 3 ounce fiberglass cloth. Then two additional layers of 8 ounce fiberglass cloth were added.  Each layer of cloth was laid down in on single piece.  I wanted to do this so that the finished part would be seamless.  The trick in getting it all down correctly without a lot of hassle was to start in the middle and then work my way outward while applying the resin.  The corners had to me handled carefully so as to not get any wrinkles.  It took a bit of doing but I managed it.

Here is a good close look at the first part in the mold.  Looks almost like carbon fiber only because of the dark gray primer under the part.  I was very happy at this point to have it look this good.  It took right around an hour to get all the layers into the mold the way I wanted them to be so I could start breathing again.  I had to hold my breath while fitting the corners and getting a nice clean layup.
After letting the mold cure overnight I started to take the first part out and had to get these photos.  Here you can see where I have already loosened the part from the mold as the color change shows in the photo above.

Here the part is nearly released from the mold.  The dark spot under the part is the only section that is still not released from the mold.  I only had to give the part one more little tug and it popped right out of the mold.  Total time to get the part out of the mold was only a minute or two.  I was thrilled it worked so well and was so easy to remove from the mold.
Here is how the part looked straight out of the mold.  The part has a very smooth finish and could be painted just as it sits but that is not my plan as all of the wedge shaped parts will be covered once the chair is assembled. Trimming came next.

I only had to take a sharp scissors to the edge of the part to trim off what was not needed on  the finished part.  Very light weight but still not completely trimmed to the size I want for the ball chair. The lip on the part in the photo above is three inches and I wanted to get that down to around two inches so more trimming was in order.

This photo shows the progression that I need to take to finish three of the six wedge pieces.  From left to right you have the mold,  then the part just out of the mold, the wedge shaped piece completely trimmed to size using a Sonicrafter tool and finally the underside showing the reinforcements that I will ad to stiffen and strengthen the part.
Here's a good shot of the underside of one of the wedges with the reinforcement foam already added to the part.  Once the foam has been added it will have a couple layers of 3 ounce fiberglass laid over the foam to give it the rigidity that I am looking for in the chair.  Only the bottom three sections of the wedge shaped inner pieces will get this treatment.  The upper three sections will not have any weight on them so the parts right out of the mold will do nicely for holding the speakers and LED lights that I have planned for the assembly. Also in all of the corners of all of the wedge pieces I have added four more layers of 8 ounce fiberglass.  This make the corners very sturdy and should do well when the parts are mounted to the interior of the chair.

Here are two of the three wedge pieces set up with the foam reinforcements ready to be fiberglassed.  The foam strip that I put in are only 1/2 inch thick and an inch wide.  I laid down 1/4 inch by 1 inch strips and then doubled them up to get the correct thickness that I wanted for this portion of the project.
  Once I have the fiberglass over these parts it should do nicely to get the strength that I want in each section.  Total hours on the project has risen to 250.5 hours now.  Even with that I still will have a lot to do before this project is complete.  But with the success of the  wedge mold cranking out perfectly uniform parts it will make the final assembly fall in to place when I get to that point.  Enjoy the update and have a good day in your workshop.  I know I have had another good one for sure.


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