azonenberg changed the topic of #homecmos to: Homebrew CMOS and MEMS foundry design | Wiki: http://homecmos.drawersteak.com/wiki/Main_Page | Repository: http://code.google.com/p/homecmos/ | Logs: http://en.qi-hardware.com/homecmos-logs/
<Noxz> just spent far too long looking for diaphargm pumps that can get to a modest vacuum, simply to keep moil mist away
<Noxz> found one that gets to 9 mtorr
<Noxz> but not sure if that's enough
<Noxz> at least no oil backflowing
<sync_> Get a scroll pump if you are worried about backstreaming
<Noxz> at 2-4x as much though
<Noxz> but, if it's needed...
<pie_> dumb idea: you could do a 3 stage pump \p/
<Noxz> how is that dumb
<Noxz> I'm still trying to figure out why some pumps perform better than others.. like obvious differences, not the minute stuff
<Noxz> maybe it comes down to minute stuff, iunno
<Noxz> especially for diaphargm pumps
<Noxz> diaphragm
<pie_> ok gon2slep o/
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<sync_> you can actually make three stage rotary vane pumps
<sync_> but they are limited by the vapour pressure of the oil anyway
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<SpeedEvil> wich can be reasonably decent
<SpeedEvil> plus, you can cheat
<SpeedEvil> Sublimation pump, for example, does quite well with oils.
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<Noxz> wow, google doesn't know mtorr meant milli torr, so when I was saying "10mbar to mtorr" it came back as torr so I was a thinking stuff was better than it was, without reading it said torr
<sync> yes
<sync> :D
<Noxz> like jesus christ, google
<Noxz> it's what allowed me to look at diaphragm pumps again, I even got my mini one and disassembled it to verify what was up
<sync> you can pump turbos with a wobl pump, but they usually are not made for very low pressures and or high massflow
<Noxz> I just really dont like the idea of oil mist (even with a filter???) coming up into a mass spec or coating the turbo
<Noxz> I'm still sorta kicking myself that the kid sold the rv12 pump :/
<sync> well then get a scroll pump
<sync> but be aware that they will wear out quickly if you cycle them often
<Noxz> doh
<Noxz> are the filters for oil pumps any good?
<Noxz> oil=vane
<sync> they help, but they are not great
<sync> but it depends on what you do
<sync> in general, you'll be fine
<sync> if oil contamination is an issue you can always change to another type of pump and clean everything
<Noxz> I'm likely looking at atleast 3 applications... SEM, Mass Spec, and Metal Deposition (via maybe 2 ways, sputtering and evaporation)
<sync> none of those is critically sensitive to oil
<Noxz> maybe not in the home lab...
<Noxz> I thought mass spec was fairly sensitive.. but maybe it depends where the turbo is placed?
<sync> no, but again it depends on what you do, you will see some peaks that belong to the oil but in general you can get away with it
<sync> if you want to do srs bsnz mass spec, you will need to get a commercial unit anyway
<Noxz> well, the idea is to make my own tripple-quad
<Noxz> that's one of the big projects
<Noxz> w/ the turbo setup
<Noxz> which I am still waiting on dude to post it
<Noxz> will likely click buy once he does though, nothing else on there is a fulls etup like he is offering
<Noxz> but I wonder if his 1mtorr vane pump would actually work well for it or not.. and I havent found anything in a decent price range on there that can do less
<Noxz> just a thought and looking a little on the internet, havent found too much yet beyond "probably not" .. if the tesla turbine could work as a vacuum pump, to any real degree
<sync> it is not a positive displacement pump so it cannot work at high pressures and it has only one aperture so it will be a very bad turbopump
<Noxz> right, just another turbine.. k
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<sync> yes, also how to spin it?
<Noxz> motor
<Noxz> that's how all these other pumps are spun
<Noxz> people usually demo it with compressed air spinning it and measure the rpm, not too much on the ways of showing it as a genny or in reverse operation(via a motor)
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<kanzure> yes it's still active
<mircea_popescu> orly ?
<mircea_popescu> !~seen azonenberg
<mircea_popescu> god damned no bots omfg how do people live.
<Noxz> he pops onto the chemistry channel from time to time
<Noxz> he was making a solid-state camping fuel chunk
<Noxz> but, not often
<mircea_popescu> aha.
<Noxz> I haven't seen too much discussion of ongoing projects, beyond my own.. I could be mistaken though.. but I certainly get some questions answered.. currently working towards a high vacuum system
<diginet> Noxz: I am slowly working on my own photoresist
<diginet> but I recently moved, so the project is on the backburner, still getting settled in
<Noxz> diginet, I am likely going to try to make my own PMMA with my own chlorobenzene
<diginet> Noxz: why PMMA, are you going for electron
<diginet> ?
<Noxz> Yeah, one of the projects with the vacuum is going to be a Scanning Electron Microscope
<mircea_popescu> interesting.
<Noxz> kid hasn't posted the turbo yet
<diginet> who?
<Noxz> some kid that made a fusion reactor ;)
<diginet> oh
<Noxz> 15 year old
<diginet> plenty have
<Noxz> who has a bunch of leftover vacuum stuffs
<diginet> fusion doesn't interest me
<Noxz> nah, but his turbomolecular pump + controller+ coolant lines etc etc etc does
<diginet> I am intentionally designing a vacuum free process
<Noxz> I use vacuum for chemistry stuff often enough, that going lower shouldn't be all too difficult
<Noxz> a little annoyed with prices though
<Noxz> and oil mist
<Noxz> (the idea of, mist)
<diginet> oil-less is the way to go if you can
<Noxz> yeah, looks like scroll pump will be the only kinda that can really deliver on it
<Noxz> as a roughing pump
<diginet> a turbomolec can use a diaphragm pump as backing
<diginet> it must have a molecular stage though
<diginet> I am interested in the challenge of a vacuum-free process though
<diginet> my apartment doesn't have room for a ton of equipment, and I'm on the fourth floor of a walk up
<Noxz> I will be converting a bedroom into a lab, I wanted to make a shed outside, but property lines are a bitch
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<diginet> yeahhhh
<Noxz> looks like the available turbo pump actually wants an oil-free diaphragm of <= 5 mbar (3.75 torr)
<diginet> that sounds good
<mircea_popescu> why not just buy / rent a warehouse ?
<diginet> $$$
<diginet> and convenience
<mircea_popescu> i c.
<Noxz> and being in your house is convienient
<Noxz> like, I have a dog
<Noxz> and these experiments would be at night
<mircea_popescu> let me put it another way : if you actually prefer living in a warehouse, why are you not.
<Noxz> some warehouses dont like night time work
<Noxz> others run on night time, lol
<Noxz> warehouses are not for living ;)
<mircea_popescu> says who ?
<Noxz> yuo get kicked out for 'squating'
<Noxz> if anyone finds out
<mircea_popescu> eh get out. recall the "artist collective" that nearlyu burned to death ?
<diginet> I can't even imagine what a warehouse would cost to rent in NYC
<mircea_popescu> whole schtick of these is "get people living in warehouse".
<mircea_popescu> diginet so rent it in nj like everyone has done since forever.
<Noxz> mircea_popescu, I do, because I was there setting up a rave a month before....