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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

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

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

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

I worked for an outfit who bought consumables and hardware from Duniway on a regular
basis. Their staff are knowledgeable - at least the ones I spoke to - and they do
not sell junk, as far as I can tell.

No vacuum vendor will survive long selling lousy stuff, the market is too small.
Duniway has the best prices I've found anywhere, and I've had no trouble with
anything I've bought from them for my personal use.

I think I might worry a little bit about dual-use oil, until I know more about
it. It seems to me just a little hard to believe that an oil good for DP operation
will also have sufficient high-pressure lubricity to preserve the bearing surfaces
in my mechanical backing pump. I admit to ignorance, but the requirements for the
two applications are so different - with the exception of possessing low vapor
pressure when cold, obviously, that it just seems wiser to me to use what the
manufacturer's recommend: DP oil in the DP, mechanical oil in the mechanical
pump.

On Feb 13, 2013, at 8:36 AM, Vaughn Mcdowell wrote:

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 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.

- Bill "Gomez" Lemieux,
The Highland Tinker

On 14/02/13 02:36, Vaughn Mcdowell wrote:

...

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.

For rust-removal, evaporust is good because it dissolves rust instead of converting it like other stuff. It works better when warm > 20-25degC.
Complete immersion or continuous spraying with a jet is best.

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
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.

You could make an oil mist output filter using a car oil or air filter.

Yeah, you can't use anything even slightly abrasives to remove rust
from any of the bearing/wiping/sliding surfaces such as shafts and
vanes and valve seats and so forth.

If there is pitting or a change in the shape or surface quality of
the cleaned steel, that part is scrap.

On Feb 14, 2013, at 5:22 AM, Russell Shaw wrote:

On 14/02/13 02:36, Vaughn Mcdowell wrote:

...

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.

For rust-removal, evaporust is good because it dissolves rust instead of
converting it like other stuff. It works better when warm > 20-25degC.
Complete immersion or continuous spraying with a jet is best.

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
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.

You could make an oil mist output filter using a car oil or air filter.


------------------------------------

Yahoo! Groups Links

- Bill "Gomez" Lemieux,
The Highland Tinker

On the gasket where the case parts split - is that RTV?

There's no chance any RTV got inside the pump or any
oil-wetted surfaces is there?

I'm probably stating the obvious, but I don't think you
want an aromatic acid like acetic any where in your
vacuum system, for both obvious reasons.

OTOH, if you've flushed the pump and its backing a DP
well, that would sorta prove the pudding, I suppose. :)

- G.

On Feb 14, 2013, at 3:25 PM, Vaughn Mcdowell wrote:

Opps my last link should be

- Bill "Gomez" Lemieux,
The Highland Tinker