Where to find cheap-ish turbos?

[krfkeith]

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]

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.

[Nick Peskosky]

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!

[krfkeith]

Wow! I appreciate the answers!

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.

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.

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.

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!

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.

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?)

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.

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.

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]

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]

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]

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.

[John Futter]

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]

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]

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.

[Richard Hull]

John is just being mindful of folks who are capable of following a point from A to B without being spoon fed statement after statement from the previous posting with follow up responses like, "wow my jaw dropped" or... I didn't even know this or that existed as a response to the quote. Worse still, are quotes within quotes, (probably some sort of internet art form, I guess).

Speak your mind, impart information or ask questions as needed related to any prior post. Most folks who pack the gear needed to do fusion are, indeed capable of absorbing and following a post's thread. They are clever that way.

I usually refresh by saying "in regard as to what is the best grid material, I have found that..........." This keeps your flow going and not someone elses, perhaps, less than perfect missive.

Your replies should be yours and not one half to three quarters of someone else's.

Richard Hull

[krfkeith]

Richard,

As the adminstrator of these forums, I respect your freedom to enact rules as you see fit. That being said, don't you think the way in which you responded was just a bit too, well, condescending? Moreover, don't you think it's rather elitist and self-congratulatory to essentially to say that people who find it easier to follow threads with quoting are dull, and that people who build fusors are above such plebeians? I mean, obviously it takes some dedication to make one, but it doesn't make you some kind of genius, nor does it make people without the inclination to do so stupid. And preferring quotes as a stylistic choice especially doesn't either. I dunno, I guess what I'm saying is that there are ways to disagree without basically calling those who do idiots in so many words.

[Carl Willis]

Block-quoting and nested block-quoting are new to members who got accustomed to this forum over the decade or so before conversion from W-Agora to phpBB just this summer. It's clear there are divergent opinions on the subject. My own feeling is that nothing in this thread has crossed an obvious line. I think we can put a cork on the raging. And break it out on the occasion when some asocial mongoloid has the temerity to use the post quote button! (I'm sure we won't have to wait long.)

So there was a discussion about cheap turbopumps. My own menagerie of turbos came largely from the sale of old CRT evacuation equipment that landed on eBay last year. Most of those were the Pfeiffer TPH-065, sold as-is for $90 each by one seller who had many dozens of them. Periodically another lot surfaces. I obtained four pumps: three working pumps and one with a damaged rotor. I know a number of other fusioneers grabbed these pumps as well. This particular pump has a lower bearing that is easy to replace with a part that can be obtained from a bearing manufacturer for about $30. It is "rumored" to be the same bearing that Pfeiffer uses, but neither Pfeiffer nor the manufacturer will acknowledge that outright. The lube wick costs about $70 and is available from a local vacuum supply house here in Albuquerque. I also have a couple "pumping stations" based on the Alcatel ACH-31+ baby turbopump. In contrast to the Pfeiffer, there is nothing user-serviceable about this pump. Precision tooling is required to disassemble it. My suggestion is to keep a search going for more of the Pfeiffer TPH and TPD-series pumps. The driver board, TCP-035, is often held by the same person selling the pump, but neglected. The TCP-015 is a complete driver with the TCP-035 board, a switching power supply to power it, and a chassis with nice panel buttons. These, however, are rarely let go cheap.

-Carl