Orion
26-06-2005, 08:19 PM
I started a knew thread because I didn't want to get off the subject in another.
Quote; On friday I decided that I should make a plaster mould to make a lap tool. I used my nicely ground mirror (I was half way through the 9 micron stage). I put a little bit of cooking oil on the mirror and proceede to pour in the plaster. The plaster stuck onto the mirror and I couldn't remove it. I should have known this as this exact same thing happened when I made my grinding tool. I started to remove the plaster and no go. I left the mirror and the plaster in water overnight. The next day I removed it.It came off quite easy (with a little tap on the side). To my horror I discovered that I had two new scratches on it. I have had to go back 3 grits to remove them(320 grit). I tried going back one grit at a time but it was all in vain. While I was doing this I ran out of some grits and now I have to wait one week to get some more. So one moment of stupidity has cost me one and a half weeks grinding. Live and learn Ha. So those contemplating grinding their own mirrors these are some of the trial and tribulations you may go through. still all good fun. End Quote.
Cristian Before you pour the plaster onto the glass I would put some Gladwrap on the mirror first and then put on the sides for your dam. I use dental stone instead of plaster because it is water proof. ( I hope your painting the plaster before you pour the pitch on)
Quote; On friday I decided that I should make a plaster mould to make a lap tool. I used my nicely ground mirror (I was half way through the 9 micron stage). I put a little bit of cooking oil on the mirror and proceede to pour in the plaster. The plaster stuck onto the mirror and I couldn't remove it. I should have known this as this exact same thing happened when I made my grinding tool. I started to remove the plaster and no go. I left the mirror and the plaster in water overnight. The next day I removed it.It came off quite easy (with a little tap on the side). To my horror I discovered that I had two new scratches on it. I have had to go back 3 grits to remove them(320 grit). I tried going back one grit at a time but it was all in vain. While I was doing this I ran out of some grits and now I have to wait one week to get some more. So one moment of stupidity has cost me one and a half weeks grinding. Live and learn Ha. So those contemplating grinding their own mirrors these are some of the trial and tribulations you may go through. still all good fun. End Quote.
Cristian Before you pour the plaster onto the glass I would put some Gladwrap on the mirror first and then put on the sides for your dam. I use dental stone instead of plaster because it is water proof. ( I hope your painting the plaster before you pour the pitch on)