Where to find cheap-ish turbos?

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krfkeith
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Where to find cheap-ish turbos?

Post by krfkeith » Mon Aug 26, 2013 7:41 am

I've talked to a number of people on various places on the internet who claimed to have acquired sub-$200 turbos. Is that even possible? Is it mostly just a waiting game? What are good places to look for them. eBay? Where else?

Thanks for your help
-Kevin

Ross Moffett
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Re: Where to find cheap-ish turbos?

Post by Ross Moffett » Tue Aug 27, 2013 4:13 am

I scored a turbo-molecular pump with a controller just last week. The auction was for pump only, but after a PM to the seller he shipped me the pump with burned out controller for $200.

As far as I can tell, <$200 turbo-molecular pumps are going to be in need of overhaul / cleaning. If you're not prepared to do that, I don't know if I'd risk it. I've been looking for one occasionally (spot checking every couple of months) for about a year and this was the best deal I had seen. I've narrowed down some faults in the power supply of the controller, and found a busted bearing while cleaning out dirty oil throughout the pump (see turbo-molecular pump maintenance thread for a glimpse of what this is like). This is day one.

Diff pumps have shown up multiple times at $80-$150. Probably I would go this route if I weren't planning other high-vacuum experiments where a turbo-molecular pump is more convenient.

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Nick Peskosky
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Re: Where to find cheap-ish turbos?

Post by Nick Peskosky » Tue Aug 27, 2013 6:43 am

Welcome to the board Kevin and per the guidelines please follow this post up with an introduction about yourself. Now getting down to the thick of it, quality TMPs are notoriously difficult to come by while meeting three parameters we fusioneers care most about A) low cost B) includes all the pieces (i.e. pump, controller, arbitrary interconnecting cable) and C) in functioning order. I paid 200$ + shipping for my Alcatel 5150 and 100$ + shipping for the matching CFF 450 controller and cable, both were sourced from eBay auctions. The pump required some cleaning but was in overall good shape. The controller on the other hand needed a fair bit of electrical repair, to include replacing two worn out relays and a front panel switch (relatively basic soldering/de-soldering/probe work). The take away from this should be that everything you receive from eBay is likely a mixed bag unless it is warranted by the seller, or the seller specifically has demonstrated that the components were sourced from a working system. Now on to tips and tricks on how to score a turbo-pump:

1. Set-up a watch list on eBay under the business/industrial section and consider the following keywords: turbomolecular, high vacuum, lebyold, alcatel vacuum, varian vacuum, turbo pump, high vacuum pump, ultra high vacuum, tmp vacuum. I'd recommend checking the list for new arrivals almost every other day because when deals do pop up, they move FAST.

2. Also look for helium leak detectors, mass spectrometry systems, TEM, SEM, vacuum deposition chamber systems -- these are often hidden goldmines which contain a TMP/numerous vacuum gauges/kf hardware. In the past two months I have watched 2 systems with a Varian V60/Turbovac050 pump respectively be scooped up for <300$.

3. Don't forget about all in one systems! Danielson Tribodyn units (although the company is now defunct) often appear at least once a month on eBay for <500$ and include a turbodrag pump/controller/backing pumps. There are also numerous self-contained Varian, Pffiefer, and Edwards units that make their rounds from time to time.

4. If an auction says the rotor/stator blades are bent or that they "don't spin freely" you're done looking. Unfortunately, TMPs are not like car engines where they can be rebuilt in you garage with a little patience. If the precision milled vanes of the pump are damaged or the bearings are worn out, the pump is essentially scrap metal because the cost to repair far exceeds what you will pay for a second hand pump in a eBay auction .

5. When buying a controller and pump separately, always ask the seller via private message if they possibly have the matching cable for the pump laying around in one of their components lots. This will save you an exponential hassle on the back end of playing 'find the magic jig-saw fit'.

6. Although many would consider this ancillary to obtaining a turbomolecular pump because even finding one at a good price is believed by many to be as probable as spotting a unicorn, take into consideration the type of inlet/outlet flange hardware the pump has. ISO fittings are easily re-configurable and inexpensive while Conflat flanged turbos will have to likely be conically or straight-nipple reduced and then throttled in some fashioned before connecting to your chamber.

I've seen this question arise many times and from someone who has "done the impossible", I figured I'd share my insight. Happy hunting!
Nick Peskosky
NPeskosky@gmail.com

"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein

krfkeith
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Re: Where to find cheap-ish turbos?

Post by krfkeith » Tue Aug 27, 2013 2:31 pm

Wow! I appreciate the answers!
Ross Moffett wrote:I scored a turbo-molecular pump with a controller just last week. The auction was for pump only, but after a PM to the seller he shipped me the pump with burned out controller for $200.

As far as I can tell, <$200 turbo-molecular pumps are going to be in need of overhaul / cleaning. If you're not prepared to do that, I don't know if I'd risk it. I've been looking for one occasionally (spot checking every couple of months) for about a year and this was the best deal I had seen. I've narrowed down some faults in the power supply of the controller, and found a busted bearing while cleaning out dirty oil throughout the pump (see turbo-molecular pump maintenance thread for a glimpse of what this is like). This is day one.

Diff pumps have shown up multiple times at $80-$150. Probably I would go this route if I weren't planning other high-vacuum experiments where a turbo-molecular pump is more convenient.
$200 is definitely within my budget. And considering the relative bargain of a turbo at that price, I'd be more than willing to do some work on it. As for diffusion pumps, I know that they're cheaper but I'd honestly like to avoid them for reasons I will make more clear below.
Nick Peskosky wrote:Welcome to the board Kevin and per the guidelines please follow this post up with an introduction about yourself. Now getting down to the thick of it, quality TMPs are notoriously difficult to come by while meeting three parameters we fusioneers care most about A) low cost B) includes all the pieces (i.e. pump, controller, arbitrary interconnecting cable) and C) in functioning order. I paid 200$ + shipping for my Alcatel 5150 and 100$ + shipping for the matching CFF 450 controller and cable, both were sourced from eBay auctions. The pump required some cleaning but was in overall good shape. The controller on the other hand needed a fair bit of electrical repair, to include replacing two worn out relays and a front panel switch (relatively basic soldering/de-soldering/probe work). The take away from this should be that everything you receive from eBay is likely a mixed bag unless it is warranted by the seller, or the seller specifically has demonstrated that the components were sourced from a working system. Now on to tips and tricks on how to score a turbo-pump:
No problem, I'll make sure and do that right after this. In terms of the controller, I know there was a long-ish thread on this subforum concerning a DIY controller for a specific model turbo. Generally speaking, could that be done for other models? While I am by no means an expert, I think I am somewhat competent with respect to electronics. And I hear you about eBay being a mixed bag, I've been burned too many time to count.
Nick Peskosky wrote:1. Set-up a watch list on eBay under the business/industrial section and consider the following keywords: turbomolecular, high vacuum, lebyold, alcatel vacuum, varian vacuum, turbo pump, high vacuum pump, ultra high vacuum, tmp vacuum. I'd recommend checking the list for new arrivals almost every other day because when deals do pop up, they move FAST.
I'm sure they do! I'll go ahead and follow you advice here, I have a few other watch lists for similarly obscure (well, for hobbyists anyway) things.

Nick Peskosky wrote:2. Also look for helium leak detectors, mass spectrometry systems, TEM, SEM, vacuum deposition chamber systems -- these are often hidden goldmines which contain a TMP/numerous vacuum gauges/kf hardware. In the past two months I have watched 2 systems with a Varian V60/Turbovac050 pump respectively be scooped up for <300$.
Now, here is where I suppose I should say why I am interested in a turbo to begin with. I hope it's okay, but I actually only signed up for this forum because it seems to be one of the few places on the internet discussing high vacuum equipment. I'm actually somewhat uninterested in fusors. My purpose in pursuing all of this is to attempt some physical vapor deposition. Thus why I would like to avoid diffusion pumps: they make for a major headache when you're trying to avoid contamination. Now, I am vaguely aware of what you are saying, that things like electron microscopes and vacuum deposition equipment contains turbos, but are you telling me one can acquire a SEM system or a vapor deposition chamber for less than $300!?!? While I don't have a specific use for it, I would almost kill for a SEM of my very own!
Nick Peskosky wrote:3. Don't forget about all in one systems! Danielson Tribodyn units (although the company is now defunct) often appear at least once a month on eBay for <500$ and include a turbodrag pump/controller/backing pumps. There are also numerous self-contained Varian, Pffiefer, and Edwards units that make their rounds from time to time.
I didn't even know such a thing existed! I'll definitely keep an eye out.
Nick Peskosky wrote:4. If an auction says the rotor/stator blades are bent or that they "don't spin freely" you're done looking. Unfortunately, TMPs are not like car engines where they can be rebuilt in you garage with a little patience. If the precision milled vanes of the pump are damaged or the bearings are worn out, the pump is essentially scrap metal because the cost to repair far exceeds what you will pay for a second hand pump in a eBay auction .
I understand if the blades are physically destroyed then forget about it. However, concerning the bearings, couldn't they be replaced? While they aren't exactly cheap, all ceramic silicon nitride bearings are entirely out of sight (I've seen them for $100 a pop). Is that what turbos use? Also, is it possible that a unit might appear not to spin freely because it uses magnetic bearings and isn't powered up? (I would imagine turbos that use them would use active magnetic bearings?)
Nick Peskosky wrote:5. When buying a controller and pump separately, always ask the seller via private message if they possibly have the matching cable for the pump laying around in one of their components lots. This will save you an exponential hassle on the back end of playing 'find the magic jig-saw fit'.
Don't even get me started on "special" connectors.
Nick Peskosky wrote:6. Although many would consider this ancillary to obtaining a turbomolecular pump because even finding one at a good price is believed by many to be as probable as spotting a unicorn, take into consideration the type of inlet/outlet flange hardware the pump has. ISO fittings are easily re-configurable and inexpensive while Conflat flanged turbos will have to likely be conically or straight-nipple reduced and then throttled in some fashioned before connecting to your chamber.
That was actually another question I've been wondering (how exactly to connect it to the chamber) anyway.
Nick Peskosky wrote:I've seen this question arise many times and from someone who has "done the impossible", I figured I'd share my insight. Happy hunting!
Thanks so much!

Ross Moffett
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Re: Where to find cheap-ish turbos?

Post by Ross Moffett » Tue Aug 27, 2013 3:21 pm

krfkeith wrote:
Nick Peskosky wrote:4. If an auction says the rotor/stator blades are bent or that they "don't spin freely" you're done looking. Unfortunately, TMPs are not like car engines where they can be rebuilt in you garage with a little patience. If the precision milled vanes of the pump are damaged or the bearings are worn out, the pump is essentially scrap metal because the cost to repair far exceeds what you will pay for a second hand pump in a eBay auction .
I understand if the blades are physically destroyed then forget about it. However, concerning the bearings, couldn't they be replaced? While they aren't exactly cheap, all ceramic silicon nitride bearings are entirely out of sight (I've seen them for $100 a pop). Is that what turbos use? Also, is it possible that a unit might appear not to spin freely because it uses magnetic bearings and isn't powered up? (I would imagine turbos that use them would use active magnetic bearings?)
My turbopump has one shot bearing. There are two open-faced hardened steel bearings identical in dimensions to skateboard bearings (if you're familiar with those). I was able to find all-ceramic high-speed, high-temp replacements for $30/ea but don't expect to be so lucky.. I doubt they all use the same bearings. Some use magnetic bearings. My costs are $200/pump + $25/shipping + $70/bearings + $25/misc electronic for repairing the controller so far. I wasn't really expecting it to be this pricy, but then I didn't think to ask the seller if it spun freely AND did not wobble on its axis.

The other concern is that these things are spinning at 30k+ RPM sometimes. If both bearings fail, all bets are off. That thing is going to eat itself up inside. Looking at the one taken apart on my bench, I noticed all shafts/rotors had little drill marks on them. The manufacturers were removing milligrams of material to balance the shafts at high speed. I wish I'd had the great advice you read from Nick before purchasing my pump.

krfkeith
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Re: Where to find cheap-ish turbos?

Post by krfkeith » Tue Aug 27, 2013 5:24 pm

Ross Moffett wrote: Looking at the one taken apart on my bench, I noticed all shafts/rotors had little drill marks on them. The manufacturers were removing milligrams of material to balance the shafts at high speed. I wish I'd had the great advice you read from Nick before purchasing my pump.
Wow. I had to practically pick my jaw up off the floor. I can't even begin to imagine how something that stupid could ever sound like a good idea.

Ross Moffett
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Re: Where to find cheap-ish turbos?

Post by Ross Moffett » Tue Aug 27, 2013 5:36 pm

krfkeith wrote:
Ross Moffett wrote: Looking at the one taken apart on my bench, I noticed all shafts/rotors had little drill marks on them. The manufacturers were removing milligrams of material to balance the shafts at high speed. I wish I'd had the great advice you read from Nick before purchasing my pump.
Wow. I had to practically pick my jaw up off the floor. I can't even begin to imagine how something that stupid could ever sound like a good idea.
It is a good idea. It's how they balanced the pump when it was made. :)

My point is that it's an extremely precise instrument, and bumps and bruises have a huge effect since the manufacturer bothered to make such small modifications.

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Re: Where to find cheap-ish turbos?

Post by John Futter » Tue Aug 27, 2013 6:39 pm

Kevin and Ross
please stop reposting what others have said
It is unnecessary, burns up site storage, and makes reading posts tedious

As For Turbo bearings most are special using nonstandard dimensions ie metric outer and imperial inner and nonstandard width. Also the bearing manufacturer will not sell to you as they recognise the part as a custom made for one customer exclusively.

Ross Moffett
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Re: Where to find cheap-ish turbos?

Post by Ross Moffett » Tue Aug 27, 2013 7:57 pm

If you don't like quotes, disable them in the forum. They're an optional feature, like everything else, but:

Quotes are a tool for people who think in a point-by-point way, unnecessary for folks who are better able to aggregate and respond elegantly to large amounts of information. When not using quotes, I find that I ramble to make clear which particular points I'm responding to. Please consider that not everyone processes information in the same way that you do, which is why quotes are widely used in forums across the internet.

Site storage should hardly be an issue when it comes to storing plain text. That hasn't been a problem for at least 10 years.

Quotes are boxed so that they're easy to ignore. New, original content shows up un-boxed. They can be irritating, space hogging (like advertisements), but you aren't forced to read them.

krfkeith
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Re: Where to find cheap-ish turbos?

Post by krfkeith » Tue Aug 27, 2013 7:59 pm

John,

I can't imagine the storage space required to save quotes would be anything but negligible. In fact, apart from things like images, I highly doubt the entire forum database and records from the beginning amounts to much more than a few megabytes.

The only reason I quoted what others said was to make it clear what I was referring to. Otherwise, it can be confusing where the conversation is going. Also, it can be tedious to have to scroll up and down, for example with a list of points, to see which response applies to which point. That being said, I do find it obnoxious when people quote a huge wall of text only to respond with a single sentence comment, which, if you'll notice, I didn't do.

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