Preparation

Before getting started on a mold for the Ful-Vu lens, there were a few things I wanted to take care of.  As luck would have it, I had a broken lens that I could experiment with to try some things. For any given casting project, there are probably a number of different ways of going about it.  Having already completed most of what is detailed here before writing about it, there are probably a few things I would change, but since it worked I will write about what I did, then add what I should have done. Because of the shape of the Ful-Vu lens, I knew it would have to be some sort of two-part mold, rather than just a simple one piece.  I struggled for a while with the design, but eventually came up with an idea I thought would work.  The first thing I needed to figure out was how to non-permanently attach the lens to the mold box I was constructing, as I didn't want it to move around as I was pouring the first half of the mold.  This is where the broken lens was helpful.  I could try some different adhesives without worrying about damaging my good lens.

 

I decided to try using Mighty Mend-It to fasten the lens to the wood I was using for my mold box, as it shouldn't be permanent on these materials, yet should bond good enough to keep the lens from moving.

   

Thin bead of adhesive around lens should keep silicone from going underneath.

 

I let this set up overnight and then made sure it would hold tight, and that I could remove it again without damage.

 

 

After I was satisfied with my adhesive solution, I started working on the box that would contain the mold as it was setting up and hardening:

 

 

 

 

The basic box size is not much bigger than the outside dimensions of the lens.  For most objects, you shouldn't need more than a half inch of thickness at any given point.  Even less thickness would probably work, but I didn't want to take any chances.

 

Because this was going to be a two part mold, and I would eventually pour the resin for the lens from the top (the bottom in the picture above), I needed the box to be the exact height as the lens itself.  The reason will become clear later.  This is one of the things I would do differently if I were making another mold, but it ended up working ok as-is.

 

So first I got an exact measurement of the height of the lens:

 

This picture is not dead on, but you can see the height is just about 3 3/16" high.

 

 

So I cut the sides of the box down to 3 3/16" on my table saw, and screwed everything together:

 

Here it is with the lens set in place.

 

At this point we are just about ready to pour, however I do want to mention one other thing.  While this lens is in great shape overall, you probably noticed it has a few defects:

 

Decent sized chip out of the bottom.

 

Some more minor chipping along the bottom edge.

 

 

As this story goes on, I will discuss a couple different ways these defects might be dealt with during the process, depending on how much time or money you want to devote to them.