[Ian, Daniel]

In spite of my old proclamation, I decided to clean the 4.5 in CF Gate Valve from Alan Rice. All the materials are stainless steel, with two exceptions: some nylon is press fit into stainless steel parts to reduce friction, the gasket to seal the gate valve when closed is made of viton. I did the standard 10 minute sonication in Simple Green:DI Water 1:30, DI water, and isopropanol. I did the following batches: the main body with the CF knife edges, the top with the bellows and screw that allows for actuation, the inside parts (including the parts with nylon, which is fine according to LIGO's methods, section 12.2), and two outside parts which don't touch the vacuum. I am baking at 200°C all purely stainless steel parts that will go into vacuum. On Friday, I will clean the viton according to this procedure, replacing the pressure cook with a shorter sonication and baking out at 120°C for 48 hours. I will finally clean the nylon/steel parts at 80°C for 24 hours.

We need to get cleanish stainless steel screws to assemble the part: 1/4-28 socket head cap screw, 1 5/16” long (qty. 12); 1/4-28 nut (qty. 12); #6-32 socket head cap screw, 3/8” long (qty. 4); #10-32 socket head cap screw, 1/2” long (qty. 1). The 1/4-28 parts can be used from the CF Flange screws (1 1/4" long screws are too short and we have many extra nuts). I got the other screw types from the MCE shop.