latex prototype

Because of the wrinkles, I am trying to use latex to make the inner shell.  Latex is stretchy and should form better to the amputee's leg.  The weather balloon provided one source of latex.  Using contact cement, I connected the balloon to the outer plastic shell and made the full shape.  The weather balloon functioned well when attached to a vacuum with a bottle inside.

 

The weather balloon as the inner shell surrounded by coffee grounds

-Annie

Baby Bottles

I want the attachment between the vacuum and the shell to be easily to come apart.  The way I thought to do this was with threaded pieces.  I have used coke bottles and nebulizers to do it so far but I wanted to look into other options.  Coke bottles are more available than nebulizers, but nebulizers work better.  My new solution is baby bottles.  The baby bottles worked fairly well but didn't attach well with my vacuum hose.

 

The baby bottle next to an assembled attachment

 

 The unassembled attachment

-Annie

Weather Balloon

So the latex 646Q balloons didn't work as well as I had hoped for a flexible inner shell, but the latex seemed to be heading the right direction.  To create the shell I tried a weather balloon.  It's huge and flexible.  The challenge is to glue latex to itself and the plastic components. To connect the balloon I used contact adhesive.  

 

The balloon leg shell

-Annie

Plastic Wrinkles

The plastic bag has wrinkles when the vacuum is applied.  This will cause error in the mold and maybe create a mold that is unusable.  It the wrinkles are extreme, the socket made from the mold will not fit to the individuals leg.  To stop this problem a stretchy material may be used.  I started working with large latex balloons, but though they were the correct size inflated they started very small. 

 

inflated balloons are the right size 

 

the deflated balloons are too small to put a leg into

-Annie

Working on Aesthetics

To increase the durability of the AspiraMolde's outer shell, I am using fabric patches to cover it.  The nylon patches have adhesive on the back that does not need to be heated (not iron-on) but this limits the size.  The largest patches are 8"*8", so there are a lot of edges.  I have been trying to work on a method to keep the edges from peeling up while being flexible, I don't want it to fall apart.  I've tried Plasti-dip, epoxy and bathroom caulk to seal the edges.

 

On the left: plasti-dip covering the edges

On the right: edges with out plasti-dip

 

  

Epoxy covering the edges

The plasti-dip worked well and kept the bag very flexible.  The epoxy was better at holding the gaped pieces of nylon patch, but it was stiffer and cracked when bent.

-Annie

Hot Wax

I melted the wax down and poured it into the prototyped AspiraMolde.  The problem was that I didn't wait long enough for the wax to cool off before I poured it into the opening.  The plastic bag couldn't stand the heat and the seal gave way and the wax was sucked into the vacuum.  Because of the damage caused by the wax I had to modify the bag.  I still wanted to see if the bag could if withstand heat of the wax while it was cooler.  I cut the end of the inner shell out and sealed it back together smaller. Then, put the coke bottle back in the prototype and applied the vacuum.  It hardened and I poured the cooler wax in.  This time it didn't hurt the plastic, but the vacuum disconnected. The coffee and shell lost its hardness briefly  briefly before the vacuum was turned back on.  The finished shape doesn't really look like the coke bottle because of this deformity.  The wax did solidify though and I was able to remove from the bag once the vacuum was turned off.

 

Wax being removed from the bag

 

-Annie

Wax Positive Mold

To test my prototype, I wanted to make a positive mold from the negative and see the similarity in shape.  I got paraffin wax and a large pot to melt it in and today I melted some of the wax.

 

Paraffin melting inside the pot

 

large blocks of paraffin and the pot on a heater

-Annie