Black Friday Tool Auction

[MRDucks2]

Went to a Black Friday Tool Auction my brother pointed out an old friend was having at his auction house. Rockler MDF Melamine Router table top with fence, plate and mount for a Bosch router all on an oak stand - $165, early version Drill Doctor 750 with extra Diamond wheel, looks nearly unused - $65, my favorite of the day, small medical vacuum pump on stand - $75 (a little dirty but draws full vacuum and whisper quiet).

Plus a day with my brother, nephew in law and great nephew.

 

[Dalecamino]

Nice!

 

[MRDucks2]

Learned a bit more on the vacuum pump. It is a Gast vacuum pump/compressor power by a 1/6 HP GE motor. 1.1CFM, 20 psi, 20" vac.

Rebuild kits are still available and consist primarily of seals for the pump housing. New the pumps run about $600 but they can be readily found in the surplus market for about $100. They are "liquid ring" vacuum pumps with only 1 moving part and no contact parts.

What does this mean: obviously the 1.1 CFM is going to take 3 times longer to pump down than the 3 CFM rotary vane I have. I will be curious how this this affects what I call "bubble overload". Because of the design they are not susceptible to vapor intrusion into the pump and they are designed/often do run 24/7 for years without maintenance or issues. Not only is it whisper quiet, it produces no smoke/emissions.

Plus mine is mounted on a cool cart.

I am have several applications to try including degas of resin, primary stage vacuum for stabilizing (bubble load) or secondary stage vacuum for holding vac on those critical jobs, even though I have a well sealed chamber, and finally a second chamber for my wife's jewelry resin.

 

[Dalecamino]

This is interesting. So it takes 3 times longer. Less likely to ruin it like I did.

 

[KMCloonan]

Learned a bit more on the vacuum pump. It is a Gast vacuum pump/compressor power by a 1/6 HP GE motor. 1.1CFM, 20 psi, 20" vac.

Rebuild kits are still available and consist primarily of seals for the pump housing. New the pumps run about $600 but they can be readily found in the surplus market for about $100. They are "liquid ring" vacuum pumps with only 1 moving part and no contact parts.

What does this mean: obviously the 1.1 CFM is going to take 3 times longer to pump down than the 3 CFM rotary vane I have. I will be curious how this this affects what I call "bubble overload". Because of the design they are not susceptible to vapor intrusion into the pump and they are designed/often do run 24/7 for years without maintenance or issues. Not only is it whisper quiet, it produces no smoke/emissions.

Plus mine is mounted on a cool cart.

I am have several applications to try including degas of resin, primary stage vacuum for stabilizing (bubble load) or secondary stage vacuum for holding vac on those critical jobs, even though I have a well sealed chamber, and finally a second chamber for my wife's jewelry resin.

I have a newer Gast pump that I picked up in the 1980s. I built a plastic bag veneer press with it, and it works wonderfully. The pump works tirelessly and is very quiet.

 

[duncsuss]

... obviously the 1.1 CFM is going to take 3 times longer to pump down than the 3 CFM rotary vane I have.

I wonder if this is true.

My suspicion is that the CFM ratings are based on no resistance - that is, if the vent on your pressure pot is open, the rotary vane pump can suck 3 CFM where the Gast can only suck 1.1 CFM.

But the reality is that you're only interested in what it can pump when the vent is closed - and if your pot is 1 cubic foot (7.8 gallons), it should be possible to evacuate it in a minute or less at 1.1 CFM (or just 20 seconds for a pump rated 3 CFM).

That's probably not what happens in the real world - does your rotary vane pump really hit high vacuum in just 20 seconds?

What I'm trying to say is that you might find your Gast out-performs the rotary vane system in your real-world application.

 

[MRDucks2]

I wonder if this is true.

My suspicion is that the CFM ratings are based on no resistance - that is, if the vent on your pressure pot is open, the rotary vane pump can suck 3 CFM where the Gast can only suck 1.1 CFM.

But the reality is that you're only interested in what it can pump when the vent is closed - and if your pot is 1 cubic foot (7.8 gallons), it should be possible to evacuate it in a minute or less at 1.1 CFM (or just 20 seconds for a pump rated 3 CFM).

That's probably not what happens in the real world - does your rotary vane pump really hit high vacuum in just 20 seconds?

What I'm trying to say is that you might find your Gast out-performs the rotary vane system in your real-world application.

I am wondering about the same thing. The 3 CFM can draw the vacuum on either chamber (I have a 3 gallon and one that is closer to 3 quart) quickly. The first half of the draw down is gradual and relatively linear, the second half happens very quick.

Unless I leave a lot of headroom in the container for the juice over the wood, the bubbles create a head that you have to watch and tinker with the intake valve allowing bubbles to collapse faster than the vacuum increases.

I am wondering if the slower rise in vacuum will require less valve control or if it will not be noticeable. Plus, it is very quite and produces no smoke.