Making of Plaster tool

After reading a lot (I mean A LOT) about Telescope making, I finally made up my mind to build one for myself. My dad had bought me a telescope when I was about 13. That was about 19 years ago. It was (is, rather) really an astro-terrestrial scope and I really enjoyed watching the moon in it. Little did I realise that this small telescope is going to make a very big impression on my heart. Maybe someday I'll post a pic of my first scope.

Later I got myself a Binocular (pics later). This boosted my interest in astronomy to such an extent that I started tracking the skies on a daily basis.
Finally, I decided to have my own scope so that I don't have to wait in long queues to watch the Saturn rings.
Now I had to think about how much can I afford to spend on a decent scope. I was looking at an 8" reflector with Dobsonian mount. A decent one could easily go beyond 40K Rs. This is way beyond my budget as I have other projects lined up.
So I thought that with a little extra efforts, I can save money and also satisfy my intellect.

Yes, I decided to build my own telescope, right from making my own mirror. So I bought this 8" mirror making kit for around 3k. The kit gave me 2 glass blanks, some abrasives and the pitch.

This is the Blank measuring 200mm.

Now since I have read A LOT, I decided to save one glass blank and use a plaster tile too to do the grinding. So I bought POP and some other stuff from a local supplies shop and started with it. Created a Dam using ordinary cardboard. Applied vaseline on the glass surface as I don't want the plaster to stick to the glass. Insulated the glass with a transparent plastic paper.


The guy in the store told me that the POP would set in about 15 mins. But I learnt (the hard way) that it started setting in less than 5 mins. So I had to literally scrape the POP from the mixing container and pour into the dam. As I had expected, the disk was not even close to the mark and I had to throw it away.
Next I went out and bought another POP bag. This time I was determined to keep it in slurry form till I poured it in the dam.



This is the final product. I have kept it aside for curing. There won't be much activity here for the next couple of weeks till the disk is ready for waterproofing.