Sunday, April 19, 2015

Something in the mix

Based on the popularity of the pen making process posts from a few months ago, many people might also be interested in seeing the acrylic mixing and casting process.

Now, I don't cast all the acrylic pen blanks I use. But I did start casting acrylic since returning from Japan and the acrylics so far are quite beautiful.


The acrylic I'll use here is Alumalite. It's an easy 50/50 mix of parts A and B with a healthy set time of about 7 to 10 minutes. The label says 15, but I really need to get it under pressure before then to get the bubbles out. The coloring powder is from a gorgeous set I received as a gift. They're mostly pearl-sparkling colors.






Here is one part with a healthy scoop of blue powder with a hint of green for an aqua flavor. I mix the powder in the part B only to give me a little extra time to get it thoroughly stirred and mixed before adding the part A, which will start the clock before the acrylic hardens.





I mixed one blue and one white pearl, shown here with both parts A and B in the cups. Have to hurry now!


Ok, the acrylic is poured into the mold. The black mold at the bottom is the perfect length for the Executive pen set. There was a good bit extra from the mixing, so I had two PVC molds on standby. I place them in the pressure pot and seal the lid.

The pressure is on! 40 psi of air pressure will remove any air trapped in the acrylic from the mixing process. I'm very careful stirring, but some air gets trapped in the thick liquid no matter how you try to avoid it. Getting it into pressure before the acrylic hardens will ensure there are no voids in the finished blank.


I leave the acrylic in pressure for about three hours, long after the set time. After relieving the pressure, these blanks sat overnight, ensuring beyond any doubt they are done setting up.


And here's the finished blank, quite lovely if I do say so myself. By the way, I won't use the PVC molds any more. The first time I tried them, they popped right out with a little coaxing from the hammer. These, however, had to be cut out.



And now the fun part. Just like the previous post, the blank was drilled, glued, and trimmed. Now it goes on the lathe for shaping.


Turning leads to sanding ...


Here's the blank during the sanding process.












And here's the finished pen in its rhodium setting.  I hope you enjoyed the journey!

Please leave comments below!