Gast Vacuum Pump - Right Fittings??

[Doug Olsen]

Hi,

I am about to buy a Gast 0523 vacuum pump and need to ask about the two canisters and gauges as seen in the picture. Are these component I will need when setting up a vacuum chuck system?

The Gast is used but in excellent operating condition and I found it locally for $250 which seems in the range seen on ebay. It is offered by a medical supply surplus company.

There are other parts I'll need and I'm unsure about those as well. All of the threads I've read leave me totally confused. My knowledge about this is zero so any help will be appreciated.

Regards, Doug Olsen

 

[john lucas]

I'm not that sharp on the Ghast equipment but the 2 cylinders on the left are filters. Good things to have since you'll be working around a lot of dust. It looks like those might be vacuum gauges on top. Also a good thing to have because it will tell you if the wood is losing vacuum or in some instances you don't want full vacuum and they tell you where you are.
You'll need an on off switch and a way to bleed off the vacuum you don't need. You'll also need a way to conduct the vacuum from the pump to your chucks, and of course some vacuum chucks. All are easily built from readily available parts.

 

[Dennis J Gooding]

Doug, the canisters may be filters, but coming from a medical facility, they might be more than that. Carl Ford published an excellent report a few years ago on how to build your own system, right down to specifying part numbers in the McMaster-Carr catalog for necessary parts. I used it extensively in building my own system a couple years ago. You might want to do a Google or contact Carl regarding any recent updates to the report.

The link is: http://www.carlford.info/pages/demos_classes/vaccum_chucks_demo/Vacuum_Chucks_Demo.pdf

Dennis

 

[Mark Mandell]

Hi,

I am about to buy a Gast 0523 vacuum pump and need to ask about the two canisters and gauges as seen in the picture. Are these component I will need when setting up a vacuum chuck system?

The Gast is used but in excellent operating condition and I found it locally for $250 which seems in the range seen on ebay. It is offered by a medical supply surplus company.

There are other parts I'll need and I'm unsure about those as well. All of the threads I've read leave me totally confused. My knowledge about this is zero so any help will be appreciated.

Regards, Doug Olsen

Hi Doug,

The pump you are looking at is an oil-lubed rotary vaned pump (small bottle on the side) that will pull 4 CFM at a max vacuum of about 26"hg. There are two filters in your picture. One, on the intake side, will be a protective filter to keep particulates or liquids from being sucked in. The other, given the oil lube, is likely to be a coalescing filter to remove any oil vapor for the exhaust stream. The gauge on the intake will tell you how much vacuum you're pulling at any given time, and the 2nd gauge is likely there to monitor the output pressure which will usually be close to "0". each filter you'll see a hose barb fitting to grip your vac line from the lathe and to direct an outlet tube if you use one.

As john mentioned, you will need some good hose for the suction; semi rigid stuff that won't collapse and clog. You'll also need some plumbing fittings to make up a bleeder valve to control the suction at the lathe. 1/4 brass fittings including a ball valve will be fine, and I recommend you get another vacuum gauge to put next to your lathe and the bleeder.

You'll need a way to connect your suction line to your lathe spindle. My back connection is the E-Z Vac rod and fittings that works quite well (backup because my Stubby lathe has internal vacuum fittings built in).

Vacuum chucks are easy to make using Schedule 40 or 80 PVC drain fittings, a faceplate, and a few pieces of MDF.

There are a number of vacuum articles in the "How To" section of this site as well as on the WoodCentral Turning Articles section with pictures and diagrams of the set-up and fittings.

 

[Bill Boehme]

The unit pictured is the type that has oiled vanes in the pump.
that is what the little bottle of oil is for. The preferred type of vacuum pump for vacuum chucking is the dry vane type. The main problem with the oiled vane type is that fine wood dust that gets through the filter will mix with the oil and make a sludge that will require cleaning periodically. Here are a few other things that you will need:

• Needle valve for regulating the vacuum by letting in a tiny amount of bleed air.
• rotary coupler that connects the vacuum line to the hand wheel side of the lathe's spindle.
• vacuum gauge.
• small filter for needle valve.
• Inline air filter that goes between the rotary coupler and the vacuum gauge and bleed valve.
• vacuum chuck.

 

[Mark Mandell]

The unit pictured is the type that has oiled vanes in the pump.
that is what the little bottle of oil is for. The preferred type of vacuum pump for vacuum chucking is the dry vane type. The main problem with the oiled vane type is that fine wood dust that gets through the filter will mix with the oil and make a sludge that will require cleaning periodically. Here are a few other things that you will need:

• Needle valve for regulating the vacuum by letting in a tiny amount of bleed air.
• rotary coupler that connects the vacuum line to the hand wheel side of the lathe's spindle.
• vacuum gauge.
• small filter for needle valve.
• Inline air filter that goes between the rotary coupler and the vacuum gauge and bleed valve.
• vacuum chuck.

Won't care for the "whistling" needle valve. 1/4" ball vale is fine

 

[nicktodd]

Muffler

I have an older version(0522) of the same pump. I bought it second hand and have had 7 or 8 years of service from it. The canister on the exhaust also acts as muffler. Removing it will drastically increase the sound of it.

 

[Syd Sellers]

Hi,

I am about to buy a Gast 0523 vacuum pump and need to ask about the two canisters and gauges as seen in the picture. Are these component I will need when setting up a vacuum chuck system?

The Gast is used but in excellent operating condition and I found it locally for $250 which seems in the range seen on ebay. It is offered by a medical supply surplus company.

There are other parts I'll need and I'm unsure about those as well. All of the threads I've read leave me totally confused. My knowledge about this is zero so any help will be appreciated.

Regards, Doug Olsen

This is a great product Doug but as mentioned, it is a combo Compressor / Vacuum pump. Most of the pumps made by Gast are of this nature. The seal on the rotor is oil so you have to keep it lubed up. Also, it doesn't like moisture so if you are going to chuck up green/wet wood you will shorten it's life a fair bit.
Check out the other models Gast makes, they have a true piston type or a diaphragm type. For small jobs like Vac. chuck, I would recommend the Diaphragm, they don't mind getting wet and the dust isn't as big a deal. They too come with filters and gauges for both Vac and pressure and are much cheaper to buy and a lot easier to repair.

 

[Rob Wallace]

I own two Gast Model 0523 rotary vane pumps, both of which are "dry" oil-less pumps that run both cool and quiet for long periods as necessary (mine are rated for continuous duty). Depending on your system filtering and installation, infiltration of fine dust that invariably gets drawn into the system gets in contact with the oil of the lubricated head, and will, over time, accumulate all manner of gunk (technical term) in and around the vanes, and in the input and exit ports at the top of the pump head. The internal filters (if installed) also get clogged with dust-oil mix and need to be cleaned periodically. Been there. Done that. Also, aerosol oil exiting the pump also creates a mess, which is one of the reasons the "hanging" external filters are in place. Outflow air still can create a nice mess of oil in proximity of where the pump is installed.

Both of my pumps are oil-less and have not given me any problems with my vacuum chucking systems which have been working (fairly frequently) for over 7 years. The likelihood is that the pumps will not have any issues until the vanes are worn to the point when the pump no longer pulls the rated vacuum.

My recommendation is to keep looking for oil-less (i.e. carbon-composite vane) pumps which (as the Model 0523 specs state) will pull ~5 cfm at 26" Hg. Many of the medical replacements (some hospitals, etc. are required to replace their equipment at specific use/time intervals) of these vacuum pumps are used for aspirators and other applications, where having oil-lubricated pumps are not an issue. In the fine-dust environments we turners live in, infiltration of dust into the pump IS an issue, and one that can be avoided with obtaining a pump with a dry-vane design.

I have been re-building Gast, Sargent-Welsh, Fisher, Alcotec (and other) vacuum pumps since the late 1970s as the "lab rat Mr. Fix-it" of most of the research labs I have worked in, and I can tell you that it is a major PITA to have to strip down a pump head and clean it periodically. If replacement parts are needed, rebuild kits can be pricey. Try to avoid this if you have the opportunity, and look for a dry-vane pump. (BTW - I would rate $250 for one of these pumps as a so-so price even when compared to comparable units on eBay). There are some excellent bargains out there on dry-vane 0523's (or even 0823's), so don't give up looking. Be sure the motor voltage is what you want (some 220V units are often sold from industry from things like printing presses and graphics studios), and be sure the motor voltage is compatible with your installation voltage, since you probably don't want the added expense of additional wiring upgrades costs.

Good luck with installing your system.

I have said for years, "Once you go VAC, you'll never go back!"

Rob Wallace

 

[Rob Wallace]

I just read the post ahead of mine. I would not recommend diaphragm pumps (not sufficient air flow volume - they are not designed for these higher air flow applications) and piston pumps are quite noisy and likely have the same problems with oil and dust. The likelihood of using vacuum chucks on wet wood is quite low (unless you are doing something quite atypical), so water infiltration into the pump is usually not an issue.

Your best bet is still a dry rotary vane, continuous-rated vacuum pump - this is why this type of pump is sold as part of most vacuum systems offered by vendors such as Craft Supplies, Packard, etc.

Good Luck!

Rob

 

[Doug Olsen]

This Gast 0523 oil type is a no go.

Thank you everyone. I didn't realize what the little bottle on the side is but I have read that an oilless rotary vane is the best choice. Thanks Rob for reminding me of that. Knowing that the one I was considering uses oil, I will opt out of that purchase.

I'll continue looking for a Gast 0523 or 0823 oilless pump and I am grateful to everyone for their advice. It saved me from making an unpleasant mistake.

The Gast's I've seen on ebay have pricing all over the place. Some have fittings, many don't. And then there is the risk of it's "used" condition so I may have to buy a new one from Craft Supply's. Heck if I order it today I may win the "every 14th order is free" ... their thing for Valentines Day.

Thanks again to all of you.

Regards,
Doug Olsen

 

[Bill Boehme]

Won't care for the "whistling" needle valve. 1/4" ball vale is fine

You may have it confused with something else. There is no whistling from a needle valve unless you have a cheapo or defective one with a fluttering needle. At most, a barely audible hissing sound and even that is very soft because there is a filter installed on the inlet side of the valve -- usually something like a small sintered metal type similar to the sintered metal muffler found on Gast dry vane pumps. Further, a ball valve isn't a very good choice with respect to fineness of control to make small adjustments to the vacuum level since it is primarily intended to be used as an on-off type of valve.

BTW, for the OP there are a few other necessary parts that have not been mentioned yet -- a brass T and two ball valves. The T mounts on the inlet of the vacuum pump and the ball valves attach to the two other legs of the T. One of the ball valves vents to open air and the other is in line with the hose to the rest of the system. These two valves are used when doing the pump cool-down/shutdown procedure according to the Gast instructions for your particular pump. If you did not get that with the pump, you can find it on the Gast web site. Gast has modified the procedure on newer pumps so you will need to see what is appropriate for your particular pump.

 

[Mark Mandell]

Think you've got unnecessary parts, Bill. I have one filter [sintered] in my line to the pump [Robinair, oil, 6cfn]. My bleed valve is a 1/4" ball that allows me to adjust vacuum in 2"steps, more than fine enough for any vacuum chucking. I can see no use for an outlet valve in this application as we want the maximum amount of airflow to compensate for leakage at and through the wood. Please explain?

A friend used a needle as a bleeder, and when I had my ears "in" the pitch was uncomfortable. For those of us without high-end hearing loss, I'd suggest another valve.

 

[Steve Worcester]

I have the 1023 and it rocks. A little overkill sometimes for woodturning (10CFM-3/4HP) but a great pump.
I would hunt around ebay and look for a rotary vane, >2CFM, >23" Hg, >1/4HP. These are my preferences, any number greater than those listed is a bonus. I think I paid under $200 with shipping but it has been a few years.

Also, you are going to want to pipe the ball valve and vac gauge to where they are easy to get to and see. There are a jillion articles floating around on the plumbing, which is way easier than the diagrams make it look.

 

[Richard Coers]

I would be very hesitant to buy a pump from a medical surplus outfit. Way too many bodily fluids, and things (read bacteria and virus) floating around a hospital or doctor's office for me to attempt to save a couple hundred dollars. Buy a cheap pump, and we'll throw in a free case of MRSA. What a deal!

 

[Bill Boehme]

Think you've got unnecessary parts, Bill. I have one filter [sintered] in my line to the pump [Robinair, oil, 6cfn]. My bleed valve is a 1/4" ball that allows me to adjust vacuum in 2"steps, more than fine enough for any vacuum chucking. I can see no use for an outlet valve in this application as we want the maximum amount of airflow to compensate for leakage at and through the wood. Please explain?

A friend used a needle as a bleeder, and when I had my ears "in" the pitch was uncomfortable. For those of us without high-end hearing loss, I'd suggest another valve.

Mark,

I've seen a lot of different configurations for vacuum systems -- most of them not optimal, but still fully functional. While you may think that some of the things that I do seem unnecessary, on one level you are correct that a functional system can be put together with fewer parts. My intention is to prolong the life of the pump vanes with a $2 filter and more optimal location of the main filter to minimize build up of sticky dust in the lines and vacuum gauge diaphragm. The difference in flow rate through a piece of hose that is clear and one that has even a thin build-up of residue can be significant under some circumstances.

As for the T and two ball valves mounted directly on the pump intake, they're there IAW the Gast vacuum pump shutdown instructions. I presume that other brands of rotary vane pumps also have some sort of shutdown cycling between open and blocked port operation. I am not familiar with your oiled type Robinair. If it is a piston or diaphragm pump then it may not have any type of recommended shutdown cycling. Mine does, although none of the other woodturners who I know that have Gast pumps bother to follow those instructions.

I have several friends and relatives who have high powered hearing aids and it seems to me that they all have the propensity to squeal and whistle at the slightest provocation. So, could it be possible that the whistling is actually the hearing aid being excited by just the right frequency? Regarding whistling coming from a valve, it is possible if something is loose which is basically what happens with reed type musical instruments. I would not be too surprised if a hardware store variety needle valve whistled, but usually tightening the packing nut slightly should fix the problem. Better needle valves can be had for not much more $$.

 

[Mark Mandell]

Bill,

I do understand your wanting to keep your lines clean.

If I remember, a "shut-down" procedure on oil-less pumps is to block the intake, run the vacuum up to max which, along with getting the pump warm, works to dry out the pump's interior that's been sucking moisture to prevent corrosion.

My oil-lube pump doesn't need that procedure. Since I change the oil after every 10 hours of operation I can see that my filter is sufficient to protect everything after the "T" rig as there is no dust in the oil. I do, however get a very small amount of condensed water in the oil, hence the required change.

Biggest issue I had with the Robinair was that it's not designed to be used in an open/free-air system like vacuum chucking. Thus the air stream will pick up oil and blow it out as a micro-mist. I had to fit my exhaust with a oil coalescing filter [photo] to prevent my shop from being filled with an oil fog.

 

[Bill Boehme]

I would be very hesitant to buy a pump from a medical surplus outfit. Way too many bodily fluids, and things (read bacteria and virus) floating around a hospital or doctor's office for me to attempt to save a couple hundred dollars. Buy a cheap pump, and we'll throw in a free case of MRSA. What a deal!

Can you describe specifically the medical uses that you are thinking about?

AFAIK the types of pumps that woodturners use are for pumping air, refrigerants and some other gasses, but not fluids. Medical surplus refers to the fact that they were used in medical manufacturing such as in making vacuum formed orthotics or prosthetics.

 

[Steve Worcester]

I wouldn't have an issue buying from a medical firm, in this litigious society they have some good procedures for decontamination, the big issue is it's not a good price.

 

[Doug Olsen]

I wouldn't have an issue buying from a medical firm, in this litigious society they have some good procedures for decontamination, the big issue is it's not a good price.[/QUOTE]

Nor is it the right pump

 

[Mike Brazeau]

I have had one of these Gast pumps with the oil resevoir for over ten years and it was likely 30 years old when I bought it. I picked it up on eBay for $70 and had been used in a Canadian Federal Government lab. Have had absolutely none of the problems alluded to and it will still easily pull 25" of vacuum. I have never filled the oil resevoir. It has some oil in it and has what looks like 1/4" cotton cord in the bottle as a wick. Have the information for oil etc. but have never got around to filling it. regular detergent motor oil will work. The filters will trap any dust. Looks just like the ones I sold when I started my career with Fisher Scientific in the late 60's.

 

[Doug Olsen]

I'm happy, found one because of Larry's link. It is an oilless 1023 series Gast wired at 110 at the moment. I'll rewire it for 240v and then determine all the other components I'll need to finalize a vacuum chuck setup. I will need to do some more research on the subject to get the set up in place.

Thanks to everyone. Doug Olsen

 

[Richard Coers]

Can you describe specifically the medical uses that you are thinking about?

AFAIK the types of pumps that woodturners use are for pumping air, refrigerants and some other gasses, but not fluids. Medical surplus refers to the fact that they were used in medical manufacturing such as in making vacuum formed orthotics or prosthetics.

Specifically? You want me to describe the exact situation where a vacuum pump can be contaminated? It doesn't have to be pumping blood to be contaminated. Hospitals have a great task to keep virus and bacteria at bay, (killed my father-in-law when he contacted MSRA in the hospital). So I'm no medical decontamination expert, just wouldn't buy a scrapped item from a hospital.

 

[Bill Boehme]

Specifically? You want me to describe the exact situation where a vacuum pump can be contaminated? It doesn't have to be pumping blood to be contaminated. Hospitals have a great task to keep virus and bacteria at bay, (killed my father-in-law when he contacted MSRA in the hospital). So I'm no medical decontamination expert, just wouldn't buy a scrapped item from a hospital.

Your concerns are understandable, but in this case I think that you are worried about a situation that doesn't exist. These types of vacuum pumps are industrial equipment and would never be suitable for any kind of use where contamination of the sort that you are concerned about would be factor.

However, it is important to make a distinction. Imagine the maintenance department in a hospital having a vacuum pump for air conditioning system servicing. As you said, just being in a hospital is a good way to collect about every bad pathogen known to man, so it is not too far fetched to imagine that in addition to all the other junk in the vacuum pump that it could also collect some of those pathogens. The important point is that this is not medical equipment. It is just industrial equipment and any contaminants whether biological or chemical may or may not be worse than any other surplus industrial equipment.

Additionally, these vacuum pumps are not used in the food processing industry where there would be a possibility of coming into contact with food. As I mentioned in my previous post, the term medical surplus equipment refers to manufacturing. Because of the clean-room environment of medical manufacturing, surplus vacuum pumps are likely to be in much better condition and far less contaminated than any used vacuum pump that may have been used for who knows what in some other industrial use.