whenever I try and cover thick things with CA, or deep grooves, i always end up with some bubbles and sometimes little white dots in the cured CA. I have to believe that even though you are in Singapore, if you can get your hands on CA glue, then you can get your hands on some sort of casting resin. All you need is a mold and a couple stoppers. You can make a wood mold if you are just going to cast one or two things, then cut the mold away when done. Push the stoppers into the tubes, use a couple little sticks to hold the tubes up off the bottom a little bit, pour then wait for it to cure. If you have a tool in the shop that offers some vibration, like a band saw perhaps, then tape the mold on that tools table top and turn on the tool for 30 min or so to help shake up any bubbles. You do not need a pressure pot.
You can use clear inlace, castin craft PR, or whatever other PR, perhaps silmar 41..all easy stuff to get a hold of and comes in small quantities if need be.