A _little_ red rust makes a fine lapping compound for close-fitting metal parts... just sayin'. ;D On Feb 12, 2013, at 3:03 PM, Vaughn Mcdowell wrote: I got one frozen up too from Ebay which was supposed to have been refirbished; resisted taking it apart and realized that it was dry ( completely drained of oil and apparently sat on the shelf ). I put some oil in it and gently wiggled it ( hopping not to break the vain shaft) with some force; but with care. Believe it or not it finally gave way no longer frozen. When I flushed it I realized that the vanes were slightly rusted to the stator. Amazingly this initially frozen Welch 1400 turned out to be one of my best Ebay investments; at least if I believe my TC gauge ( less than 2 microns). Maybe you can get your frozen pump working. I feel extraordinarily lucky to have had so few complaints with roughing pumps. I lucked into my first one (a Cenco HyVac7) at an electronics surplus store who despaired of ever being rid of it. It was _well_ used (ahem) with a leaking shaft seal, no motor, not even a mounting base, for $50. It pumped okay, but the rebuild sounded like more than I wanted to take on, so I wound up giving it to another friend after someone gave me a Hyvac 14 in good working order. :) - Bill "Gomez" Lemieux, The Highland Tinker
|
Has it been a while since you ran the system? Perhaps the oil in the roughing pump needs to be warmed up and outgassed a bit through the interstage ballast valve, assuming yours has one, or the exhaust if not. How new is the oil in the roughing pump? I assume you haven't had any disasters in the chamber that could have outgassed anything. Wipe down all internal chamber surfaces with anhydrous alcohol perhaps? At that high a pressure, I think of things like water vapor or leaks. On Feb 12, 2013, at 7:55 PM, Guy Brandenburg wrote: Just tried and failed to aluminize a mirror because the pressure would not go below 1.7x10^-4 torr; as a result the coating was semi transparent. If it goes below 1.0e-4 all is good. This is unusual. Persisted even when i tightened stuff up.
Any suggestions?
------------------------------------
Yahoo! Groups Links
- Bill "Gomez" Lemieux, The Highland Tinker
|
http://www.vacuumresearch.com/pdfs/vane/pumpfluid.qxd.pdf take a look and see if this pump oil specs will work for you. 20 dollars a gallon
From: Vaughn Mcdowell
To: "VacuumX@..."
Sent: Wednesday, February 13, 2013 10:36 AM
Subject: Re: [VacuumX] RE: Welch 1402
?
It seems that vacuum pump oil price has gone up recently; for awhile I have been purchasing , from Specialty
Fluids
Co.? their type MVT-20 which is apparently a hydrocarbon dual use ( diffusion and mechanical). I have had good experience using it. I am considering their MVT-19 which costs less. I have also started using the INLAND 19 TOP QUALITY HIGH VACUUM PUMP OIL ; its in my opinion? very good . However I must confess my vacuum experience is very limited; I am in the learning mode. I am hoping to look into Duniway to see if it is a better fit to the beer budget.
Regarding the exploded
parts diagram for the 1402 pump; item 17 "center plate" is shown to be one component; I can say for my 1402 that the center plate is split into two halves not indicated on the diagram. Having semi-circular cavities facing each other also not indicated. I don't know why this is not illustrated.
Regarding freeze up besides rust rotor? and stator components keeping then from sliding; I should have mentioned when I was working on my 1402; the components were somewhat frozen ( hard to rotate the
shaft) because the rotor and stator were not lined up correctly ( as suggested from the Sam's FAQ) ; that's why I assembled it with the bolts loose then rotated the shaft with the system in oil; then later tightened the bolts; did? not have the alignment paper as discussed in the FAQ link; so I assumed this to be the next best thing working in the dark ( ie limited information found on the Web) . Another incident occured with a 1400 that I bought for very cheep had the vane rod bent keeping the vane from sliding in and out the rotor.
The 1402 that I recently got on Ebay didn't have exhaust or air intake components. With my limited knowledge as to where to get replacement components; found out the nipple replacements were outside the beer budget. After finding the required thread 1-20 I found http://www.amazon.com/dp/B000BPGRXI/ref=pe_175190_21431760_M3T1_ST1_dp_i1 and purchased three. With my metal lathe the hole was enlarged to fit a hose barb purchased from the hardware store. The intake was assembled using? solder. I then used the Loctite 592 with Teflon tape; seems to work OK.?
|
It seems that vacuum pump oil price has gone up recently; for awhile I have been purchasing , from Specialty
Fluids
Co.? their type MVT-20 which is apparently a hydrocarbon dual use ( diffusion and mechanical). I have had good experience using it. I am considering their MVT-19 which costs less. I have also started using the INLAND 19 TOP QUALITY HIGH VACUUM PUMP OIL ; its in my opinion? very good . However I must confess my vacuum experience is very limited; I am in the learning mode. I am hoping to look into Duniway to see if it is a better fit to the beer budget.
Regarding the exploded
parts diagram for the 1402 pump; item 17 "center plate" is shown to be one component; I can say for my 1402 that the center plate is split into two halves not indicated on the diagram. Having semi-circular cavities facing each other also not indicated. I don't know why this is not illustrated.
Regarding freeze up besides rust rotor? and stator components keeping then from sliding; I should have mentioned when I was working on my 1402; the components were somewhat frozen ( hard to rotate the
shaft) because the rotor and stator were not lined up correctly ( as suggested from the Sam's FAQ) ; that's why I assembled it with the bolts loose then rotated the shaft with the system in oil; then later tightened the bolts; did? not have the alignment paper as discussed in the FAQ link; so I assumed this to be the next best thing working in the dark ( ie limited information found on the Web) . Another incident occured with a 1400 that I bought for very cheep had the vane rod bent keeping the vane from sliding in and out the rotor.
The 1402 that I recently got on Ebay didn't have exhaust or air intake components. With my limited knowledge as to where to get replacement components; found out the nipple replacements were outside the beer budget. After finding the required thread 1-20 I found http://www.amazon.com/dp/B000BPGRXI/ref=pe_175190_21431760_M3T1_ST1_dp_i1 and purchased three. With my metal lathe the hole was enlarged to fit a hose barb purchased from the hardware store. The intake was assembled using? solder. I then used the Loctite 592 with Teflon tape; seems to work OK.?
|
Just tried and failed to aluminize a mirror because the pressure would not go below 1.7x10^-4 torr; as a result the coating was semi transparent. If it goes below 1.0e-4 all is good. This is unusual. Persisted even when i tightened stuff up.
Any suggestions?
|
I bought those two from a guy who had listed them on the ebay but they did not sell. He was in Atlanta, and I was there for a few months setting up a big highway job in Tampa, so I made a deal for both of them and picked them up.? I think I got them both for $125-150 or something like that.? No freight except back strain!
On Tue, Feb 12, 2013 at 3:03 PM, Vaughn Mcdowell <vaughn.mcdowell@...> wrote:
?
Yes I found out about Duniway kits for repairing vacuum pumps from the Sam's FAQ link after I had already fabricated my gaskets and used them on my pump. I haven't had a chance to check them out for future projects.
I am curious about their vacuum pump oil. I spent a fortune ( in beer budge terms) on? flushing my 1402 with oil then testing and retesting with more oil. The oil is expensive too!! The Duniway catalog price appears to be good but haven't investigated it yet. Recently to keep within my
beer budget I have purchased diffusion and mechanical pump oil from: ? and mechanical oil from
I don't know enough about the Duniway oil; which one is best for my 1402 and price comparison. I have purchased a few Welch pumps form Ebay on the cheap ( except for freight of course) that require flushing or cleaning. It seem that every time I go through the exercise of refurbishing them I have to spend $$ flushing etc.
I got one frozen up too from Ebay which was supposed to have been refirbished; resisted taking it apart and realized that it was dry ( completely drained of oil and apparently sat on the shelf ). I put some oil in it and gently wiggled it ( hopping not to break the vain shaft) with some force; but with care. Believe it or not it finally gave way no longer frozen. When I flushed it I realized that the vanes were slightly rusted to the stator. Amazingly this initially frozen Welch 1400 turned out to be one of my best Ebay investments; at least if I believe my TC gauge ( less than 2 microns). Maybe you can get your frozen pump working.
-- Nick A "You know what I wish?? I wish that all the scum of the world had but a single throat, and I had my hands about it..."? Rorschach, 1975 "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."- Benjamin Franklin, Historical Review of Pennsylvania, 1759
"Suburbia is where the developer bulldozes out the trees, then names the streets after them." Bill Vaughan "The price of apathy towards public affairs is to be ruled by evil men." Plato
|
Yes I found out about Duniway kits for repairing vacuum pumps from the Sam's FAQ link after I had already fabricated my gaskets and used them on my pump. I haven't had a chance to check them out for future projects.
I am curious about their vacuum pump oil. I spent a fortune ( in beer budge terms) on? flushing my 1402 with oil then testing and retesting with more oil. The oil is expensive too!! The Duniway catalog price appears to be good but haven't investigated it yet. Recently to keep within my
beer budget I have purchased diffusion and mechanical pump oil from: http://www.vacuumoil.com/vacuumpumpfluid.htm? and mechanical oil from http://www.ebay.com/itm/4-LITERS-MORE-THAN-1-GALLON-INLAND-19-TOP-QUALITY-HIGH-VACUUM-PUMP-OIL-/370757280683?pt=LH_DefaultDomain_0&hash=item5652db23ab
I don't know enough about the Duniway oil; which one is best for my 1402 and price comparison. I have purchased a few Welch pumps form Ebay on the cheap ( except for freight of course) that require flushing or cleaning. It seem that every time I go through the exercise of refurbishing them I have to spend $$ flushing etc.
I got one frozen up too from Ebay which was supposed to have been refirbished; resisted taking it apart and realized that it was dry ( completely drained of oil and apparently sat on the shelf ). I put some oil in it and gently wiggled it ( hopping not to break the vain shaft) with some force; but with care. Believe it or not it finally gave way no longer frozen. When I flushed it I realized that the vanes were slightly rusted to the stator. Amazingly this initially frozen Welch 1400 turned out to be one of my best Ebay investments; at least if I believe my TC gauge ( less than 2 microns). Maybe you can get your frozen pump working.
|
Re: Welch 1402 [3 Attachments]
A belt guard, how quaint!
On Mon, Feb 11, 2013 at 6:06 PM, Russell Shaw <rjshaw@...> wrote:
?
[Attachment(s) from Russell Shaw included below]
On 12/02/13 11:53, Vaughn Mcdowell wrote:
> Hi,
>
> In the next few days I plan to put new oil in my 1402 and test it again. Now
> that it seems to be reliable I want to make sure it has clean oil to be on the
> safe side; ie just in case tiny particles that may be left that could clog
> things up. At this point its worth it. Assuming it stays OK ; I have no plans to
> take it apart unless I really have to. However the exploded view could come in
> handy some day; the data sheet might be handy for checking its performance of
> for diagnosis.
>
> When you get the chance to fire up your 1402; hope things go smoothly for you. I
> could find very little information on the Web regarding details on repairing
> these pumps; the best I could find is the link Sam's FAQ ; at least he gave me
> some tips that got me through it all; having much patience was also helpful
Hi Vaughn.M,
Attached is info i saved 5 years ago.
--
regards,
Russell
-- Nick A "You know what I wish?? I wish that all the scum of the world had but a single throat, and I had my hands about it..."? Rorschach, 1975 "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."- Benjamin Franklin, Historical Review of Pennsylvania, 1759
"Suburbia is where the developer bulldozes out the trees, then names the streets after them." Bill Vaughan "The price of apathy towards public affairs is to be ruled by evil men." Plato
|
Cheap to buy, ridiculous to ship!? I have three of them.? One is seized, one pumps a bit and one is untested, still in the broken ultracentrifuge I bought for $35 from NMSU.? I think Duniway Stockroom sells the rebuild kits for reasonable amounts.
On Mon, Feb 11, 2013 at 1:04 PM, Vaughn Mcdowell <vaughn.mcdowell@...> wrote:
?
I am an experimentalist retired but have some part time contract work to help pay for my toys on a beer budget. I have some personal experiments that I want to try out with my vacuum systems. I am assuming there are others in this group in my situation; decided to provide information that might help others. I have tried finding information regarding repairing Welch vacuum pumps in order to try fixing those bought very cheep on Ebay. Recently I purchased a Welch 1402 pump, with ballast, at a relatively cheep price from Ebay. The pump was very dirty with sludge; it required extensive cleaning; I was forced to take the pump completely apart, including the ballast valve, and wash and clean it throughly. I am not claiming the following procedure is correct; but that it has worked for me.
First of all I wish to thank the following link for giving me guidance in fixing my pump:
I decided to try out making my own gaskets using the sheets given in : ; I used an Xacto knife to cut out the form for both gaskets required.
To reseal the ballast valve I use the information given in: ; from there I purchased the suggested Loctite 592 Thread Sealant 50ml ~ 59231 from:
I can't count the number of times I assembled / disassembled the 1402; in reassembling I partially tightened the bolts to allow the vanes to clear the stator without sticking. Finally I tightened them after the vanes seemed properly seated. My pump still wasn't working properly. I noticed bubbles occurring ; fixed it by adjusting and cleaning the valves. Afterward the pump seemed still weak pumping. I decided to flip the vanes each 180 degrees. I was lucky, this fixed my pump; it now pumps very fast; and seems to achieve , with moderately used oil, about 2 Microns as read by my TC gauge ( I zeroed it using a diffusion pump). I am very happy with my pump now.
I am hopping this information helps someone in this group
-- Nick A "You know what I wish?? I wish that all the scum of the world had but a single throat, and I had my hands about it..."? Rorschach, 1975 "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."- Benjamin Franklin, Historical Review of Pennsylvania, 1759
"Suburbia is where the developer bulldozes out the trees, then names the streets after them." Bill Vaughan "The price of apathy towards public affairs is to be ruled by evil men." Plato
|
On 12/02/13 11:53, Vaughn Mcdowell wrote: Hi,
In the next few days I plan to put new oil in my 1402 and test it again. Now
that it seems to be reliable I want to make sure it has clean oil to be on the
safe side; ie just in case tiny particles that may be left that could clog
things up. At this point its worth it. Assuming it stays OK ; I have no plans to
take it apart unless I really have to. However the exploded view could come in
handy some day; the data sheet might be handy for checking its performance of
for diagnosis.
When you get the chance to fire up your 1402; hope things go smoothly for you. I
could find very little information on the Web regarding details on repairing
these pumps; the best I could find is the link Sam's FAQ ; at least he gave me
some tips that got me through it all; having much patience was also helpful Hi Vaughn.M, Attached is info i saved 5 years ago. -- regards, Russell
|
Hi,
In the next few days I plan to put new oil in my 1402 and test it again.
Now that it seems to be reliable I want to make sure it has clean oil to be on the safe side; ie just in case tiny particles that may be left that could clog things up. At this point its worth it. Assuming it stays OK ; I have no plans to take it apart unless I really have to. However the exploded view could come in handy some day; the data sheet might be handy for checking its performance of for diagnosis.
When you get the chance to fire up your 1402; hope things go smoothly for you. I could find very little information on the Web regarding details on repairing these pumps; the best I could find is the link Sam's FAQ ; at least he gave me some tips that got me through it all; having much patience was also helpful
Thanks ?
|
On 12/02/13 07:04, Vaughn Mcdowell wrote: I am an experimentalist retired but have some part time contract work to help
pay for my toys on a beer budget. I have some personal experiments that I
want to try out with my vacuum systems. I am assuming there are others in
this group in my situation; decided to provide information that might help
others. I have tried finding information regarding repairing Welch vacuum
pumps in order to try fixing those bought very cheep on Ebay. Recently I
purchased a Welch 1402 pump, with ballast, at a relatively cheep price from
Ebay. The pump was very dirty with sludge; it required extensive cleaning; I
was forced to take the pump completely apart, including the ballast valve,
and wash and clean it throughly. I am not claiming the following procedure is
correct; but that it has worked for me.
First of all I wish to thank the following link for giving me guidance in
fixing my pump:
I decided to try out making my own gaskets using the sheets given in :
; I used an Xacto knife
to cut out the form for both gaskets required.
To reseal the ballast valve I use the information given in:
; from there I
purchased the suggested Loctite 592 Thread Sealant 50ml ~ 59231 from:
I can't count the number of times I assembled / disassembled the 1402; in
reassembling I partially tightened the bolts to allow the vanes to clear the
stator without sticking. Finally I tightened them after the vanes seemed
properly seated. My pump still wasn't working properly. I noticed bubbles
occurring ; fixed it by adjusting and cleaning the valves. Afterward the pump
seemed still weak pumping. I decided to flip the vanes each 180 degrees. I
was lucky, this fixed my pump; it now pumps very fast; and seems to achieve ,
with moderately used oil, about 2 Microns as read by my TC gauge ( I zeroed
it using a diffusion pump). I am very happy with my pump now.
I am hopping this information helps someone in this group Hi, I have a 1402 i got years ago that i'll use one day. I have a data sheet and exploded view diagram of its parts if needed. Thanks. -- regards, Russell
|
I am an experimentalist retired but have some part time contract work to help pay for my toys on a beer budget. I have some personal experiments that I want to try out with my vacuum systems. I am assuming there are others in this group in my situation; decided to provide information that might help others. I have tried finding information regarding repairing Welch vacuum pumps in order to try fixing those bought very cheep on Ebay. Recently I purchased a Welch 1402 pump, with ballast, at a relatively cheep price from Ebay. The pump was very dirty with sludge; it required extensive cleaning; I was forced to take the pump completely apart, including the ballast valve, and wash and clean it throughly. I am not claiming the following procedure is correct; but that it has worked for me.
First of all I wish to thank the following link for giving me guidance in fixing my pump:
I decided to try out making my own gaskets using the sheets given in : ; I used an Xacto knife to cut out the form for both gaskets required.
To reseal the ballast valve I use the information given in: ; from there I purchased the suggested Loctite 592 Thread Sealant 50ml ~ 59231 from:
I can't count the number of times I assembled / disassembled the 1402; in reassembling I partially tightened the bolts to allow the vanes to clear the stator without sticking. Finally I tightened them after the vanes seemed properly seated. My pump still wasn't working properly. I noticed bubbles occurring ; fixed it by adjusting and cleaning the valves. Afterward the pump seemed still weak pumping. I decided to flip the vanes each 180 degrees. I was lucky, this fixed my pump; it now pumps very fast; and seems to achieve , with moderately used oil, about 2 Microns as read by my TC gauge ( I zeroed it using a diffusion pump). I am very happy with my pump now.
I am hopping this information helps someone in this group
|
I am a new member interested in trying to set up A vacuum chamber to deposit metal coating on telescope mirors. Salutations
|
New Member. Introducing myself
I am building a vacuum system. I have no knowledge other than what I
have discovered on the internet and a little personal experience of what
has not worked well. I have questions.
My vacuum system (powered by a Welch 8920 two stage rotary vane pump
rated at 7.2 cfm) will serve three functions. First, a degassing
chamber for various casting materials, second, for thermoforming, and
third, as a vacuum chuck (work-holding device) for my Bridgeport milling
machine. As you can see I do not need a high vacuum. Each of these
uses will bring their own problems and having a knowledgeable source for
the vacuum portion of these problems would be great.
Right now I am building the degassing chamber.
I am a semi retired draftsman enjoying my shop and trying to be useful.
Nice to meet you.
Bruce
|
Another Noobie Project and a hello
Hello all,
As to introduce myself to the group I will spin you a yarn as to how I found myself here.
My tale starts a year or so ago learning how to cast using dental plaster for a very large 16 foot long gaming table (Hirst arts molds).
Hundreds of hours and 100 lbs of dental plaster into the project i found this amazing stuff called allumite at the local hobby lobby.
Using permission from Hirst to create my own to speed up the project, Eureka, I was now churning out 9x the amount of tiles I needed at the same time and quicker set times to boot! My sanity was saved
It was finicky stuff, super quick set times etc but it got the job done. Then the use cases started to hit me and got me thinking about being able to duplicate other one-off projects, etc.
A few months later and I've since moved to Smooth-on Products and while I've had great success I still get voids and bubbles etc.
So began my search into pressure and vacuum casting. I picked up a 3CFM pump off of amazon and a chamber/lid from Ebay for what seemed like a good price.
My first test was degassing silicone. It worked great but i didn't use a large enough cup, it nearly overflowed as i scrambled for the shutoff switch. Lesson learned! I've since been degassing my resins and pouring them into the molds I've made however its still not exactly perfect.
So I've done my homework and it looks like what I'd like to try next is a liquid feedthru for my degassed resin. I checked online and all I could find was abbess instruments. I spoke with them but they essentially would not talk to me even though I was interested with buying one of their chambers. I asked if they would sell me a liquid feed thru kit they do-not/would-not sell one. It makes me wonder how they stay in business.
Fast forward to today:
Since all I really need is to modify the lexan lid to my chamber this sound like an easy DIY. Would any of you have a site or guide how to DIY a liquid feed through?
Thoughts? comments?
Thank you for your time...
|
Veeco EP 2A 1 Diffusion Pump
I am a new member retired from the government; now do part time contract work from time to time. I purchased a Veeco EP-2A-1 diffusion pump from Ebay for a very low cost therefore willing to take a risk. I tried to get some information from the Web but couldn't find any technical information for this pump. I decided to test it out using my old version of the Welch 1405 for backing, decided to try about 70 cc of Specialty Fluids Co.version of type 704. With my limited resources it seems to work OK. However I want to make sure that the correct charge is used.
Does anyone have any information for this diffusion pump; its correct fluid charge; backing pump requirements ?? Is there some archive on the Web for vintage vacuum pumps; ie the old Welch 1405? I did find one source after spending hours searching.
Thanks
|
Vacuum Generators Limited 1GP2 Pirani Vacuum gauge controller
Hello, I've just joined this group. My background is electronics (TV), now pensioned off and I want to try my hand at some vacuum work with electron tubes etc.
I have the above controller which looks like it can read both a Pirani and Ionization gauge. I'm looking for a manual for it, schematic, instructions, etc. Can anyone help with this please.
Thanks, Don Black.
|
If your pumps are very clean, you may not need a trap.
If you are using mechanical pumps which are sealed by oil,
you will need a trap.
"clean" (no back-streaming) pumping techs include:
? turbopumps backed by a diaphragm, scroll, or dry screw roughing pump
? sorption pumps
My apologies if you stated you have existing pumps and I missed it.
toggle quoted message
Show quoted text
On Nov 27, 2012, at 11:46 AM, Attila wrote: Hi Alex,
I can explain only my experience. Actually I don't use those baffles.
Because I do IBAD coating for mirrors. During this process my ion
gun needs gas flow to work properly. To maintain a working pressure
I need as much pumping speed as possible. Those baffles, at least
what I own, reducing the pumping speed to 50-60% of the original.
This is not acceptable for me.
So if you need a clean low vacuum you should use those baffles. If
you need to maintain a working pressure(tipically 1-5x10-4 Torr),
you need high pumping speed instead.
Br.
Attila
--- In VacuumX@..., "grossmann200" <email@...> wrote:
Based on the pictures uploaded by David and Attila (thank you
both!), it is pretty obvious, that the baffle has quite some
complexity. Most likely, a baffle maybe not so easy to build on
your own.
So, there is the question:
- In which (coating-) situation do you really need a baffle?
Or to ask the way around: when would I not need such a baffle?
Cheers
Alexander
------------------------------------
Yahoo! Groups Links
|
Andrew,
Well, the Ion Beam Assisted Depositon means, there is an assisting ion source in the chamber which helps to change the physical and mechanical properities of the protective oxide layer.
That means, the ion gun only used during the overcoating.
Beacuse I make high reflective aluminium coating, called enhanched multilayer aluminium coating. Over the Sio2 layer, there is a Tio2 layer too.
And because of Tio2, I use electron beam gun to evaporate the materials.
The ebeam gun is very good controllable, especially the evaporation rate is important. And I can evaporate everything which in the periodic table exist, some materials at very high rate.
So during the aluminium evaporation, I don't use the ion source. I evaporate at 10nm/sec, at the lowest pressure possible.
After this, the ion assisting gun is turned on, and during the Sio2 and Tio2 process it hammers the atoms to the mirror surface. This way the oxide layer will have higher refractive index, totally dense(no absorption), less stress and no collumar structure.
And because of the layer thickness is precisly controlled and measured, I can make constructive intrference layer, which tunes up the reflectivity to 97%.
The IBAD process is a surface "phenomenon", that is why it works at relative high pressure(1-5x10-4 Torr), even though the mean free path is smaller at this pressure, than the source to substrate distance.
Hope this helps.
Best Regards
Attila
www.ebeamguns.com
toggle quoted message
Show quoted text
--- In VacuumX@..., Andrew Aurigema <eosraptor@...> wrote:
Attila,
This may be old to everybody else but could you explain the IBAD you have.
Is it for aluminization or SiO overcoating or both ??? I understand
tungsten coil evaporation process very well but not the others. How you
power that sort of process is what I really want to know.
Thanks in advance.
Drew in sunny Florida
--------------------------------------------------------------------
On Tue, Nov 27, 2012 at 1:46 PM, Attila <schneyolo@...> wrote:
**
Hi Alex,
I can explain only my experience. Actually I don't use those baffles.
Because I do IBAD coating for mirrors. During this process my ion gun
needs gas flow to work properly. To maintain a working pressure I need as
much pumping speed as possible. Those baffles, at least what I own,
reducing the pumping speed to 50-60% of the original. This is not
acceptable for me.
So if you need a clean low vacuum you should use those baffles. If you
need to maintain a working pressure(tipically 1-5x10-4 Torr), you need high
pumping speed instead.
Br.
Attila
--- In VacuumX@..., "grossmann200" <email@> wrote:
Based on the pictures uploaded by David and Attila (thank you both!), it
is pretty obvious, that the baffle has quite some complexity. Most likely,
a baffle maybe not so easy to build on your own.
So, there is the question:
- In which (coating-) situation do you really need a baffle?
Or to ask the way around: when would I not need such a baffle?
Cheers
Alexander
|
Nick Andrews