I recently visited an electronics surplus store. While perusing the vintage avionics section with no discernable inventory system, I caught something out of the corner of my eye.  About 10 feet up was a large box with an Atari volcano switch stuck to the front.  I quickly piled up some junk and climbed up to the box.   I brought the heavy box down and placed it on the counter.  I slowly opened it up and it was filled with tons of switches.  Unfortunately, none of them were volcano switches. However, after searching all the boxes on the aisle, I scored 3 switches that are very similar. Here is a pic:


The switch is a Licon and has the exact dimensions as the Atari version. The only difference is the lens and instead of an LED there is a mini-bulb socket.


I'm not really sure how the lens worked. It looks like something else plugged into it. Still the bottom dimensions of the lens are identical to the Atari red lens.


Therefore, all I needed was some new lens. I've already had some success casting lens for my Green Volcano buttons. Since I had to replace the bulb sockets, I figured I might as well cast clear lens and use an RGB LED. Learning from past mistakes, I designed a 2 part mold. For the bottom I used quickset RTV silicone. For top, I switched to high strength HSIII silicone, because there is a substantial amount of suction that is generated when you remove the top which tends to tear the molds.


The biggest problem with my Green Volcano buttons are little air bubbles that formed in the lens. After some research, I learned that letting the resin cure under pressure will reduce any bubbles to a size that is not visible. The pressure vessels are several hundred dollars, so I decided to improvise. I purchased a pressure paint tank with regulator on eBay for $10. I then went to Home Depot and picked up a ball valve, some fittings and an additional pressure gauge. My tank can actually withstand almost double the pressure of the expensive casting tanks. Below is my DIY pressure tank.


The tank actually worked. My first batch of clear lens looked much better than the green ones.


They are still not perfect, but I attribute this to improper mixing. The resins are supposed to be mixed by weight but I mixed them by volume because I don't have an accurate scale. I just bought a digital scale on eBay that should resolve this issue. The scale is accurate to .01 of a gram.


Here is a shot of the volcano switch with the socket replaced with an RGB LED. I used a wire drill bit to make holes for the additional leads. I soldered a 4 pin connector to the bottom of the switch and reinforced it with hot glue.


Here is a shot with clear lens inserted.


Another shot with an aluminum cone.


Here is shot hooked up to my new Rainbow circuit.


Some more eye candy. The diffused super bright RGB LED looks great even during the day.