Okay, I have been having trouble achieving a suitable vacuum. Today i replaced the o-ring seal on my diffusion pump. While I had it out I found the nameplate that said "use 50cc of DP oil. When I poured it out (much spilling) I discovered that I had way too much. Probably 100cc.
After adjusting the quantity the pump worked like new. I got to 10X10-5, without using the cold trap. I am sure that with the cold trap I will do much better.
On to coat some mirrors.
Jerry
