Saturday, March 31, 2012

Cheap grease

Look, its non silicone high vacuum grease that doesn't cost alot like Apiezon does! I got this over the phone from a lab suppliers in the UK.

Water Cooled Magnetron. A go go.

I decided to try a water cooled magnetron. My Oil Burner Ignition Transformer is rated 8000v at 34mA so thats.....8, 3s are 24.... 250watts or so. Enough to get hot in a vacuum I would think. So I made an inner brass cylinder to fit around my deep pot magnet from .5mm sheet and silver soldered it. I then made two rings of 4mm dia wire, these fit over the inner cylinder. Then an outer cylinder, brass silver soldered. I then soldered it together. The lovely copper pipe to get the water in, came from Halfords. I'm not sure why they sell it but I suspect something on the break line of cars.
So I flared the ends and drilled 4mm holes in the sleeve and soldered the pipe in place. Fingers crossed its water tight...

The seal around the inlets on the belljar is just an o-ring Wilson Seal style. Its a standard plumbing fitting altered a bit on the lathe. It is necessary to remove the first 3mm or so of thread on the 'body' of the fitting in order to allow the 'nut' to pinch the o-ring enough. I also recut the inner bevel of the body of the fitting to 45 degrees or so. It seems to work well. Plus grease of course.

The anode here is a similar setup. The loop is iron wire, well no, its a welding rod so it's probably steel !

Bell Jars, a rural approach!

I have been working on my new set up for a while now. I've been a bit busy on other projects but I'm gonna try detail some of the bits I've finished.
The first thing is the bell jar. Its made from a 'recorder jar' from a milking parlor.(Thanks again to Mr Hart!) I picked three up at local farmers auction. Cheap too!
As far as I know they were used to keep track of how much milk was being sucked out of the poor cows. We like them because they are made for vacuum use.
This is how they look in their original state. Closed at the top and bottom. An amazing piece of glass.

I went to Ireland's only scientific glass blower(details below) and got him to cut the bottom off one. It was borosilicate, the others seem to be nonpyrex glass. I'm not sure what they are made of.
The good news was that the boroglass one had two openings at the top. Perfect for the sputtering setup I was hoping for. I wanted to isolate the baseplate from the sputtering power supply.(Note: the pump and therefore the baseplate is earthed and that is the same potential as the magnetron, so this makes it not really isolated from the sputtering power supply. I don't know what else to do!)
I believe finger prints can be an issue in high vacuum, I wonder if foot prints are an issue too?!

The name of the scientific glass blowing company is Lab Glass Services. They are in The Grange, Oldtown, North County Dublin. Talk to Colm a very helpful chap! 01 8433442