Next up was prepping the small bits for molding, there is the sight, trigger, trigger keeper and the flashlight. I laid down a base of clay and filled in around the parts. The registration keys were then added. All of the sprues will be added in between pours of the two halves.



Finally comes the barrel assembly. The procedure was much same with the other box molds. I had cut out the hard board the serves as a barrier between the two halves. The came filling the gaps with clay. I filled the back side first to provide a solid structure and good bass for filling in the gaps. This way no clay with pop out and let rubber leak. Once again, lessons learned the hard way. Once the back had all be filled, I cleaned up the front added clay in the gaps and using my sculpting tools I made sure that the gaps were smoothed out. All that remains is to cut the rim boards for the two molds? Wax and spray with release and they are ready for rubber. Once the rubber is down she is all done

Hope y'all are ready for a lot of pictures... Got most of the prep work on the remaining pieces complete. I started with the pump, as it seemed to be the most complicated to me. It has a hollow center, as well as channels for the barrel assembly, which happen to connect, so I needed to find a way to separate the two rubber wise and keep the mold as simple as possible.

Here is how I went about it:

I began by blocking off the rear portion of the pump:

This will be covered later, but I wanted to ensure that if any rubber leaked past the block is would fill a small void and not the entire part.

Next I blocked off the front of the pump where the barrel assembly passes through. After blocking both the upper and lower holes, I made a registration key in each of them in order to ensure the rubber plugs would align properly.





I continued by blocking out any other portions that needed to be isolated such as the jog in the back of the pump.


The vertical piece of mdf serves as a spacer, rather than using a bunch of clay. The area that butts up against the mdf is that which was blocked out in the first picture.

Another shot:


Next I clayed in any small gaps between the part and the boards:


After that came the registration keys. I used the usual mix of magnets and cut up hot glue stick.


And finally the rim boards.

All that remains is to brush wax over the mdf and spray it down with release agent. I filled in the small gaps around the box mold with clay and hot glue to ensure no rubber leaked. With more viscous rubbers like rebound 25 you don't have to worry about such small gaps but with the moldstar30 it will sneak through any little gap you have and you will have a big mess and a lot of waste. Learned that the hard way the last time I poured. Lost almost a gallons worth of rubber through a couple little gaps in the various parts I was pouring.

For those wondering, this project hasn't died. Just had to be out on hold while life got hectic. But for those patiently waiting, there is progress!


This is the mold for the grip. In this picture it looks like a standard two part mold, but there is in fact an insert that enables the interior of the grip to be hollow to hold the trigger, spring and etc.


These two pictures show the same side of the mold, the first with the insert in place, the second with it removed. I isolated the insert with clay, including the sprue on top when pouring the two halves. I then removed the clay and poured the insert.
The insert:

Next up is the buttstock:

After this all that is left is the pump, barrel assembly and small bits.

I hope to finish up all the molding this weekend.