Substitute for Vacuum Pump Oil??

[davefr]

I bought a pretty cool Welch vacuum pump at a garage sale. It looks
like the type used to evacuate air conditioning systems.

Is there a substitute for vacuum pump oil that is locally available?
I think it's around ISO 68 (20 wt??) and from what I can tell it's
main property is low vapor pressure.

How would a good synthetic motor oil compare. (Mobil 1)? How about
compressor oil?? Is anything else close enough?

I could always buy specialty oil via mail order but it would cost way
more then the pump cost me. Is it critical to have the exact type of
oil?

[rick]

Post by davefr
I bought a pretty cool Welch vacuum pump at a garage sale. It looks
like the type used to evacuate air conditioning systems.
Is there a substitute for vacuum pump oil that is locally available?
I think it's around ISO 68 (20 wt??) and from what I can tell it's
main property is low vapor pressure.
How would a good synthetic motor oil compare. (Mobil 1)? How about
compressor oil?? Is anything else close enough?
I could always buy specialty oil via mail order but it would cost way
more then the pump cost me. Is it critical to have the exact type of
oil?

What model Welch pump did you get out of curiousity?

Dunaway has very good prices on pump oil, seal and gasket kits, springs, and
everything else vacuum related. The standard vacuum oil from them is pretty
cheap...under $20 a gallon IIRC. Some of the diffusion pump oils are quite a
bit more expensive, but that is a different beast.

Rick

[Nick Hull]

Post by rick

Post by davefr
I bought a pretty cool Welch vacuum pump at a garage sale. It looks
like the type used to evacuate air conditioning systems.
Is there a substitute for vacuum pump oil that is locally available?
I think it's around ISO 68 (20 wt??) and from what I can tell it's
main property is low vapor pressure.
How would a good synthetic motor oil compare. (Mobil 1)? How about
compressor oil?? Is anything else close enough?
I could always buy specialty oil via mail order but it would cost way
more then the pump cost me. Is it critical to have the exact type of
oil?

What model Welch pump did you get out of curiousity?
Dunaway has very good prices on pump oil, seal and gasket kits, springs, and
everything else vacuum related. The standard vacuum oil from them is pretty
cheap...under $20 a gallon IIRC. Some of the diffusion pump oils are quite a
bit more expensive, but that is a different beast.

Do you have a URL for Dunaway? My google attempts didn't work v ery
well.

[jim rozen]

Post by Nick Hull

Post by rick
Dunaway has very good prices on pump oil, seal and gasket kits, springs, and
everything else vacuum related. The standard vacuum oil from them is pretty
cheap...under $20 a gallon IIRC. Some of the diffusion pump oils are quite a
bit more expensive, but that is a different beast.

Do you have a URL for Dunaway? My google attempts didn't work v ery
well.

Common problem. :^)

Try this one instead:

<http://www.duniway.com/>

I use them for all my leak checker spares. Good
company.

Jim

[davefr]

It's model 1410.

It has an oil drain plug but there's no obvious place to add oil. I
assume you add it thru the exhaust port since that looks like part of
the oil resevoir. Either that or you lay it on it's side an add the
oil back thru the drain hole.

Post by rick

Post by davefr
I bought a pretty cool Welch vacuum pump at a garage sale. It looks
like the type used to evacuate air conditioning systems.
Is there a substitute for vacuum pump oil that is locally available?
I think it's around ISO 68 (20 wt??) and from what I can tell it's
main property is low vapor pressure.
How would a good synthetic motor oil compare. (Mobil 1)? How about
compressor oil?? Is anything else close enough?
I could always buy specialty oil via mail order but it would cost way
more then the pump cost me. Is it critical to have the exact type of
oil?

What model Welch pump did you get out of curiousity?
Dunaway has very good prices on pump oil, seal and gasket kits, springs, and
everything else vacuum related. The standard vacuum oil from them is pretty
cheap...under $20 a gallon IIRC. Some of the diffusion pump oils are quite a
bit more expensive, but that is a different beast.
Rick

[rick]

Post by davefr
It's model 1410.
It has an oil drain plug but there's no obvious place to add oil. I
assume you add it thru the exhaust port since that looks like part of
the oil resevoir. Either that or you lay it on it's side an add the
oil back thru the drain hole.

Yeah, the exhaust port works. 1410, that is a good un. I have a 1400 and a
1402. You should be able to get down to 2-3 microns if you cool the head with a
fan and new oil. I use thermocouple gauge tubes and meters to measure from 1 to
1000 microns (1 millitorr to 1 torr) bought new off ebay for around $6 per tube
and I think $25 for the meter. Look for Hastings or Varian on ebay. Of course
if you are just deflating car tires with it or something, you may not need this.
:-)

Oh, and sorry about misspelling duniway, heh heh.

Rick

[jim rozen]

Post by davefr
It's model 1410.
It has an oil drain plug but there's no obvious place to add oil. I
assume you add it thru the exhaust port

Yep. That's how it's done on those.

Jim

[Dev Null]

Post by davefr
I bought a pretty cool Welch vacuum pump at a garage sale. It
looks like the type used to evacuate air conditioning systems.
Is there a substitute for vacuum pump oil that is locally
available? I think it's around ISO 68 (20 wt??) and from what I
can tell it's main property is low vapor pressure.
How would a good synthetic motor oil compare. (Mobil 1)? How
about compressor oil?? Is anything else close enough?
I could always buy specialty oil via mail order but it would
cost way more then the pump cost me. Is it critical to have the
exact type of oil?

Yes, it is critical to have the exact type of oil. I am (almost)
certain that you have an oil sealed pump. You need an oil that has
a very low vapor pressure (no volatile fractions) for everything to
work right. The primary purpose of the oil is NOT lubrication!

There is a LOT of information on the web.

[bw]

Post by davefr
I bought a pretty cool Welch vacuum pump at a garage sale. It looks
like the type used to evacuate air conditioning systems.
Is there a substitute for vacuum pump oil that is locally available?
I think it's around ISO 68 (20 wt??) and from what I can tell it's
main property is low vapor pressure.
How would a good synthetic motor oil compare. (Mobil 1)? How about
compressor oil?? Is anything else close enough?
I could always buy specialty oil via mail order but it would cost way
more then the pump cost me. Is it critical to have the exact type of
oil?

There are several "types" of vacuum pump oil, as I recall, the Welch used
"type 19"
Based on just looking at authentic pump oil pours, ISO 68 is a pretty good
guess. If you are not planning any critical pumping, I'd guess any hydraulic
oil would work.

[brownnsharp]

I have a similar pump which I run with ordinary motor oil. The vacuum
pump oil will buy you the ability to meet the manufacturer's
specifications, which you will not meet with motor oil because of the
vapor pressure. Capella oil, from Texaco works pretty well. It is
formulated for refrigeration purposes, and is low in volatility. If
you smell a bunch of odors from the oil, don't use it. I never use
hydraulic oil for anything. Stinks, leaves sticky residue behind,
irritates the skin.... I don't know what's in it, but it reeks of
New-Jersey-Chemical-Plant.
Capella oil, on the other hand, has almost no odor, and when it gets
on you hands, the skin is very happy. And motor oil... well it is
available EVERYWHERE..

brownnsharp

[Wild Bill]

I spotted some vacuum pump oil at a farm/tractor supply store a while ago
that was under $10/gallon, IIRC (for milking pumps).

When I mentioned it here as a possible low cost alternative, someone
suggested that it would be smarter to to use the manufacturer's recommended
oil. Another comment was made that cautioned against the cheap oil, since it
would require a lot of the proper oil to flush it out.

Like your deal, I got a Welch (1405 maybe) for about $7, and had checked the
Welch prices.. about $20/quart, I think.

I still haven't tried out the pump, so it's just sitting around with
whatever was in it when I got it.

WB
..................

Post by davefr
I bought a pretty cool Welch vacuum pump at a garage sale. It looks
like the type used to evacuate air conditioning systems.
Is there a substitute for vacuum pump oil that is locally available?
I think it's around ISO 68 (20 wt??) and from what I can tell it's
main property is low vapor pressure.
How would a good synthetic motor oil compare. (Mobil 1)? How about
compressor oil?? Is anything else close enough?
I could always buy specialty oil via mail order but it would cost way
more then the pump cost me. Is it critical to have the exact type of
oil?

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