Vacuum pump pledge! (interested in outer-space? Optics? Nuclear fusion?)

[Sci]

As you probably know, we recently got the major parts of a high-vacuum
system that we can reassemble into a system that will let hackspace
members play with plasma, fusion, x-rays, outer-space environments,
custom thermionics, electron microscopes, and optical coatings (such as
mirrors for telescopes and faux-chrome on plastic).

One part missing from the equipment is the backing/roughing pump. It is
a primary component. The pumps offered by other space members are sadly
not up to the task. None can get pressure low enough, or have a high
enough pumping speed.

Amazingly a suitable pump has just appeared on ebay.

Not just suitable in fact, but the BEST advised match pump for the
diffusion system, an Edwards RV12.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=220872063639

It has a good service history, and would be ideal for our purposes. If
we can get it without others bidding against us, the total pledge would
be �150. �95 for the pump, �40 postage, �15 few fresh oil.

The retail for this model pump is �2200.

http://wiki.london.hackspace.org.uk/view/Pledges/Vacuum_Pump

The pledge is starting at �70, so we only need another �80. Four people
pledging �20 would do it to get the minimum. Any more improves our odds
of getting it in the face of counter-bids. Any surplus can go toward
other vacuum system parts.

Please pledge, this would give the idea of "Hoxton Space Center" some
real credibility.
And make stuff from the laser-cutter shine like chrome.

Sci

[Sci]

Well we've had a couple of additional pledges, and since I'm going into
my overdraft anyway I've put a bid on it.
Hopefully we'll get some more pledges, but if we don't I think this
thing is ideal enough that it's worth it the bank fines.

Sci

[Mark Steward]

The point of pledges is to determine whether there's demand for something.  Please keep passive aggression off the list.

Regards,

Mark

[Russ Garrett]

On 13 October 2011 01:55, Mark Steward <marks...@gmail.com> wrote:
> The point of pledges is to determine whether there's demand for something.
>  Please keep passive aggression off the list.

Well, I don't think that was passive-aggression, but give people a
chance! I just pledged.

--
Russ Garrett
ru...@garrett.co.uk

[Mark Steward]

On Thu, Oct 13, 2011 at 1:58 AM, Russ Garrett <ru...@garrett.co.uk> wrote:

On 13 October 2011 01:55, Mark Steward <marks...@gmail.com> wrote:
> The point of pledges is to determine whether there's demand for something.
>  Please keep passive aggression off the list.

Well, I don't think that was passive-aggression, but give people a
chance! I just pledged.

Fair point, apologies for the imputation.

I think it's generally bad practice to have retrospective pledges - that sort of thing works out fairer if people pay for using the item.

The vacuum project's still awesome either way :D

Mark

[Sci]

Was supposed to denote eagerness and a measure of how significant an
opportunity it is, not passive aggression.

Sci

[Sci]

That said, my apologies if I came across as blunt trying to express
that. It is quite late at night.

Sci

[Sci]

There's a bit under 2hours to go now. We've currently been outbid by a
new bidder at �212.
I have a nasty feeling they're going to have put a price on it a fair
bit higher, possibly pushing that �300 approx maximum I mentioned on the
pledge page.

If there's no more pledges to add, then we'll have to say this is a lost
cause now. :(
Current pledges stand at �240, which minus the �40 carriage is only �200.
Any last minute contributions to boost our bidding limit anyone? (or
someone who can collect it from Portsmouth & save the carriage cost)

Sci

On 12/10/2011 19:26, Sci wrote:

[Sci]

Sadly we did not win the RV12 pump. Bidding ended at �258, excluding the
�40 postage. :(

There is currently only one potentially suitable alternative on ebay for
under �300, but it's precise model is unknown.
It's Edwards range number would suggest it's of suitable power, but
until the seller replies with the precise model number so this can be
verified I will not attempt to bid. It ends in just under 5 days,
bidding starts at �100 with �50 postage.
http://www.ebay.co.uk/itm/280755438166
It's service history is unclear, but aside from some (possibly) cosmetic
damage to the terminal box it looks in good order and has been working
recently.

More information as it becomes available. I have altered the pledge page
to match.

Sci

PS;
On an upside, there are what appear to be some vacuum gauge controller
boards listed currently. They are cheaper than the previous controller
option but the seller is uncommunicative so there's a lot unknown about
them. I suspect they're displayless interface boards for automated
monitoring. I'll likely take a gamble on them with my own money since
they're very cheap and of unknown utility. If I'm guessing right though
it'll just mean figuring out a data protocol to read the information.

On 12/10/2011 19:26, Sci wrote:

[Nigel Worsley]

Sci wrote:
> There is currently only one potentially suitable alternative on ebay for
> under �300, but it's precise model is unknown.

> http://www.ebay.co.uk/itm/280755438166

> It's Edwards range number would suggest it's of suitable power, but
> until the seller replies with the precise model number so this can be
> verified I will not attempt to bid.

Did they respond? Is it suitable?

Currently �165 plus postage at cost (not the arbitrary �50 guess in the listing) and ends in less than 3 hours.

Nigle

[Sci]

They did, that was our bid winning. The pump was three times more
powerful than needed. Sadly it went outside of our budget again today a
few hours before end.
Shame really, the seller was particularly nice and approachable.

Ended at �295, plus the �50 postage (I had talked with them about
courier postage in email before bidding). �100 over our pledge budget.

There are currently no other pumps meeting the necessary spec and listed
starting inside the price range. Will keep my eyes peeled for more.

Sci

[Nigel Worsley]

> The pump was three times more powerful than needed. Sadly it went outside of our
> budget again today a few hours before end.

Bugger!

> There are currently no other pumps meeting the necessary spec and listed
> starting inside the price range.

So what is the necessary spec?

Nigle

[Sci]

On 20/10/2011 13:52, Nigel Worsley wrote:
>> The pump was three times more powerful than needed. Sadly it went
>> outside of our
>> budget again today a few hours before end.
>
> Bugger!

Yup.

>> There are currently no other pumps meeting the necessary spec and listed
>> starting inside the price range.
>
> So what is the necessary spec?

An ultimate pressure of equal to or less than 0.9mbar (9x10^-1mbar) and
a pumping speed equal to or over 9.7m^2/h^-1 (cubic meters per hour).

Each on their own isn't too hard to find, but both together is currently
awkward.

For future reference though, the simplified Edwards pump "size" number
(in this case 30) refers to the approximate pumping speed in cubic
meters per hour (in this case 32). Just about any Edwards pump ranged 10
or over should do, but this should be checked first. The whole range
should have sufficient ultimate pressure.
Of course it doesn't need to be an Edwards pump as long as the spec is
right.

Sci

[Nigel Worsley]

> An ultimate pressure of equal to or less than 0.9mbar (9x10^-1mbar) and
> a pumping speed equal to or over 9.7m^2/h^-1 (cubic meters per hour).

This one seems to meet the spec:
http://www.ebay.co.uk/itm/OVP-0-1mBar-VAKUUMPUMPE-VAKUUM-PUMPE-224L-MIN-UVP-549-/310228605269?pt=K%C3%BChltechnik&hash=item483b10d955

0.1mbar, 13.44 cubic metres per hour and under �200 delivered. And it is NEW!

Nigle

[M]

I know nothing about this stuff, but you ahve written 0.1mbar, but the
requirement was 0.9. unless I'm mistaken.

--
>
++++++++++[>+>+++>++
+++++>++++++++++<<<<
-]>>>+++++++.>++++++
+++++.+++..---------
.++++++++++.<<+++.<.

[Nigel Worsley]

> I know nothing about this stuff, but you ahve written 0.1mbar, but the
> requirement was 0.9. unless I'm mistaken.

For the ultimate pressure lower is better. The Edwards ones go down to 0.001 mbar.

Nigle

[Sci]

On 20/10/2011 15:14, Nigel Worsley wrote:

Well spotted! I was limiting my searches to within the UK, but shipping
on this isn't bad at all.
Spec certainly looks right. Ran it through google translate. It does
look like cheap build quality, but I guess we're not going to be doing
full-scale industrial work.

Been working all night, so will double-check again come morning before
committing. I do notice the seller has another pump type listed for �25
more with a 0.0005mbar ultimate vacuum, but can't think if we need that.

Again, good find! Will deal with once awake and coffeed'.

~ Sci

[Sci]

On 20/10/2011 15:14, Nigel Worsley wrote:

Okay, looking at this again in the light of day. It looks like it should
be fine. Found spec's listed on another site to confirm:
http://www.50512.com/P_view.asp?pid=363

It lists the pumping speed a little lower, but still within spec.

And the other pump they list is �50 more, not �25 as I said. This is why
I'm trying not to use ebay late at night. ;)
http://www.ebay.co.uk/itm/310199617352
http://www.kanpus.com/show_imgnews.asp?id=1097

The bigger one would be nicer, as the better ultimate pressure means
it'd probably have a lower risk of oil-vapour getting back into the
system. But isn't *technically* necessary. It would mean being able to
get down to decently low pressures without engaging the diffusion pump
though.
I do also note the larger one is also the only one mentioned as having a
gas-ballast valve, which would make it possible to remove moisture
build-up from the pump oil and adjust for contamination.

There's enough in the pledge for either. I'd say it's the difference
between getting good and very good service out of what we buy. I'm
inclined to say for �50 it's a difference we'll notice.

Sci