Vote for vacuum pump(s) for the vacuum former

Could the stand be built to contain the vac. pump and also dampen the noise, at least somewhat?

Any interest in the ShopVac(r), now?

John2pt0

Dave,

Thanks for getting the pump. I think I also found the oil for the pump, it should be in the email thread.

I agree that the stand could hold the vacuum pump in an enclosed space with sound deadening material on the inside. Won’t make it stealthy, but will probably cut the racket down by a factor of 3.

We use a high vacuum pump at my work for some microscopy work and it isn’t that loud. Probably depends on the model.

We also need to get some vacuum tubing to get from the pump to the former.

I’m also not sure what fitting the pump has on the inlet. The pump description talks about 1/4" MFL (which I think means “male flare”) and 1/2" ACME.

Most of these things are minor ones we can address once we get the pump.

Send Jim your receipt(s) and you will get reimbursed.

I found a 1/4"FFL to 5/16" barb on Amazon ($5.63):

http://a.co/f96jNnG

This should let us use 5/16" ID tubing to get to the former.

Hose clamps ($5.19):
http://a.co/7guioWn

5/16" silicone vac hose ($14.95):
http://a.co/2DHEaNu

The vacuum pump and oil are ordered and due to be delivered late Saturday.
Robinair (15500) VacuMaster Economy Vacuum Pump - 2-Stage, 5 CFM
Robinair 13203 Premium High Vacuum Pump Oil - 1 Quart

Item(s)Total before tax: $210.44
Estimated tax to be collected: $14.73
Grand Total: $225.17

I’ll get fittings from Harbor Freight or Grainger after the pump arrives and we can be sure of layout. 3 foot AC charging hoses with fittings go for $10 at Grainger. With one of those we might only need some pipe nipples. Oil separator from HF for exhaust is under $6.00. An oil separator may not be necessary.

Noise elimination is best done from the source or at your ear. Surrounds have been problematic in my experience. Concrete and cast iron work well. Sheet metal and plywood can wind up beating like a drum.
Depending on the pump noise level, we may need vibration isolation mounts to keep the base from transmitting / amplifying the pump vibration. Rubber vibration isolators for 50# loads are under $2 each from Grainger.

Let’s do the engineering with hands on the parts.

Dave

Great. Thanks for working on it.

Submit your receipts to Jim for reimbursement.

I agree on the source as the best place to eliminate the noise.

I’ve found that well built enclosures can help lessen the “bite” of noisy equipment though. They do have to be sturdy so they don’t resonate. I enclosed my shop vac in my home workbench and it is much more tolerable. We humans tend to be more sensitive to certain frequencies so things can be dramatically improved with some simple steps.

Let’s not do anything till we get a sense of the real noise from the pump. We even have a fancy noise meter that someone donated. It is in the hand tool area in a labeled case.

We still need to get some plastic sheets to do some vacuum forming. I think Lorin knew of some local supply places where we could get some.

Thanks again,

Brad

I have a smallish buck already made, we can test on. I would love to know that local plastic supplier. If not I have some thicker PETG we can possibly use, I have to measure it

Dave:

Pardon my delay to make this post. Thank you for stepping up to front the money and make this procurement for the Hive. I will contact you off-line to get you promptly reimbursed with Hive funds.

JimD - Hive13 Treasurer

I can help with the sound proofing. Rotary vane pumps are primarily noisy above 600Hz, 1k+. An air-gap would be the trick. 60 Hz could be deadened with rubber mounts, although I have a source for some architectural types that might be better for this light machine (grainger mounts are expecting a very heavy load).

Why couldn’t we locate the vacuum pump farther from the machine, like, say, outside like a window planter? That would decouple it with the neighbor’s apartment. Masonry walls are great absorbers and diffusers, unlike the beams and planks that shoot sound upstairs in our main space…

The vac pump and oil have arrived. The pump has soft rubber feet for vibration isolation. Filled with oil and ran the pump in the driveway to get an open sound field. 90 dB noise comes mainly from the exhaust port. Sound spectrum app on phone shows peak just above 1 kHz. No big surprise. Hand cupped over the exhaust port cut noise on meter to 80 dB. Slight white vapor from port. Many posts state this is oil and should get vented away or captured in a separator.

Let’s get a design for the vacuum former stand started, then purchase the pump connections.

Alternative to a steel frame is a heavy sided box with acoustic foam liner for sound damping.

Perhaps a box from 3/4" MDF = cheap + heavy. 4x8 sheet is $20 at HD. Router a step on the edges then glue it together. Add casters and we have a stand.
Vacuum pump and plastic sheet should probably be kept separate if the exhaust vapor contains a hint of oil.

If heat from former is a concern I’ve got some extra 1/2" concrete hardie backer board for the top surface.

I suspect we will find other uses for a vac pump. example: vacuum chuck for wood lathe, easy way to remove the compression foot from a bowl. Need to pull 20" to 25" of vac. I’m thinking of making a vac chuck for the hive lathe. This would mean a ‘portable’ solution to the vacuum pump rather than permanent mount to the stand.

We may want to add a vacuum gauge. For the exhaust noise, perhaps a muffler like this link could be printed or milled. The guy claims 10 dB reduction.

See you all on Tuesday.

Cool.
We can look at it Tuesday.
I may stop by Monday if our household calms down.

We could certainly make a separate vacuum cart that could be scooted around as needed. That way people could do cool vacuum stuff.

We have a 220v super vac in the tool shelf area. I fired it up and got quite the oil mist exhaust. Another member donated two other nice vacuum pumps but I think they are 480v. They are in the Annex. I think having this 110v one is more convenient.

Good times.

Brad

I am personally against taking this Vacuum pump and making it for multiple uses, mostsly because in the past items like that are what vanish, get lost or otherwise become unusable.
To a smaller degree, this is why we put the wrenches on wires for the CNC router
The Mist is common, my small vac pump also puts off the mist. from what i gathered its common

I could adapt the muffler to the pump and print it.

I also have about 50lbs of 3" thick sound insulation roxul mineral wool (not fiberglass, the stuff made of rocks). That’s what we use professionally for 1k band. Absorption coefficient of 1.05 at 1k. That would take care of a lot of sound if we go with an enclosure.

If we use this, It should be faced with fabric (burlap is fine for this) and mounted with an air gap 1"-2" between wool and exterior ply (this is the important trick – sound would rather bounce off ply, but if absorption layer is coupled, it will rattle the pywood (the surface would be a wool/ply composite, not a layer of wool preventing sound from hitting ply). Air gap “traps” sound and lowers the effective frequency response.

We should deal with the misting somewhat, as even a fine mist of water is considered toxic if inhaled (just ask anyone who uses an airbrush). The $100 commercial solutions seem overblown. I think something DIY could work, although there seems to be little precedent via my googling. Nonetheless, a mini vacuum hepa filter would do a little something, wouldn’t it? Or, at least directing the mist off via tubing. Breathing submicron oil is not too healthy.

L

The separators I’ve seen are basically a mesh muffler with an enclosure. The air velocity is reduced a great deal and the oil collects on the mesh and drips down into the enclosure.
I’ve also seen a foam filter that gets saturated with the oil.
I think we can engineer something to work. If only we had a mill & lathe . . .

Yes, but first we have to have develop long, complicated mailing list discussions which lead to a solution so complex our only option is to give up. Remember the laser?

So, to get things rolling, how about a catalytic converter stage and a 40,000 volt electrostatic element as well?



From: Brad Walsh
Sent: Monday, September 4, 2017 11:09 AM
To: cincihackerspace@googlegroups.com
Reply To: cincihackerspace@googlegroups.com
Subject: Re: [CHP] Re: Vote for vacuum pump(s) for the vacuum former

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The separators I’ve seen are basically a mesh muffler with an enclosure. The air velocity is reduced a great deal and the oil collects on the mesh and drips down into the enclosure.
I’ve also seen a foam filter that gets saturated with the oil.
I think we can engineer something to work. If only we had a mill & lathe . . .

Roll of toilet paper and a coffee can.

A $5.49 oil separator from Harbor Freight is number one on my list.
It’s used for air lines and can handle 80 cfm at 100 psi.
Shouldn’t be any problem to handle the 5 cfm from the vac pump exhaust.

Also like the HEPA shop vac filter idea. Cylinder pleated paper filters are under $10. We could recycle ones that are too dirty to use in a shop vac. Thinking of that, my shop vac is due for a change soon. Cut sheet metal to close top and bottom. Hold it together with an all thread rod up the middle, add flare nipple for tubing. Set it in a plastic tub so years worth of oil vapor doesn’t drip. Or, just duct tape it. If that doesn’t hold use a coat hanger. Think how cool that will look hanging out the side of the cabinet. :wink:

Either of those would probably work for a long time then just replace.

Harbor freight, to the rescue. Still, though, it just seems too simple…