$15 electric vacuum pump for anyone!

Was reading in another post about how a Rena air pump could *easily* be converted to a vacuum pump by simply rotating a piece inside the case. Thing is they cost upwards of $40… I purchased a $10 Whisper40 air pump ($15 with s/h) thinking I could convert it to vacuum then re-sell it for a profit. It turns out that converting the new whisper air pumps to vacuum is just as easy just take a look.

6 - completed vacuum pump
7 - pump with cover removed
8 - diaphram and valve (when used as a compressor)
9 - diaphram and valve (when used as a vacuum)

It draws a vacuum of 5” HG in under 2 seconds. I bet a Whisper10 would work quite well although the price difference between a 10 and 40 is not huge so I would go with the 40 which is the largest Whisper pump (with 1 air port and of this type of pump).

Where did you buy this?

EBay

I could convert this to computer control for under $100 and/or DC power for portability. Then again a low power inverter is only a few dollars so maybe DC is pointless except maybe for use on a small boat but then why would anyone be doing that? Working on a super cock while fishing for the big one? Multitaking? J/K

I wonder if they sell them at wallmart or somewhere local. I want to start pumping the whole package.

Thought the Whisper40 came with a splitter but its not a splitter its a valve! =>

You can buy them at Wal Mart and save the shipping. The manufacturer is Tetra, so look for the Tetra Whisper 40 in the pet section of Wal Mart. (The pumps are made for fish tanks)

Do not buy a Tetra Whisper 10. They do not have enough power. Make sure to buy the Tetra Whisper 40.

I have been using this pump for a long time now and just love it. The only problem is there is a big variation in the vacuum they draw after you convert it from pressure to vacuum. Mine draws a vacuum of 3 to 3.5”hg which is perfect for me, because that is my preferred pressure to pump at. I know another guy on line with the same pump that draws 6.0”hg and Smertios says his draws 5.0”hg.

The pumps do come with some rudimentary pressure adjustment valves, so some pressure adjustment is available. The only way I can tell what pressure I am drawing is to pump up with the Tetra, then disconnect the Tetra from your cylinder and connect your regular hands pump with gauge and read the pressure.

One other thing, the pump I bought at Wal Mart has 2 pressure outlets, so I just plumbed them together, and when you convert the pump, you have to rotate 2 of those pumps inside the casing to complete the conversion. You do not have to buy anything extra to plumb the 2 outlet ports together as the pump comes with a “T” fitting to do this. You might also want to buy a little extra tubing at Wal Mart while you are there.

I do love pumping with this pump though. Hands free pumping is fantastic and the pump is very quiet, as you would expect a fish tank pump to be! :)

Great idea thanks!

The attached photo shows several things about how I made my Tetra pump connections.

First, you can see the 2 outlet ports from the bottom of the pump and how I plumbed them together using the tubing and “T” connector from the Tetra box. It also shows how I was able to connect the small diameter tube from the Tetra to the larger diameter tubing from my cylinder be just inserting the smaller tube inside the larger tube. The last thing to point out is the quick disconnect to the cylinder. After getting a stable vacuum from the Tetra that is where I connect my regular hand pump with gauge to find out what pressure the Tetra is pulling.

What is not shown are the 2 pressure regulating valves that also come with the pump that can be added as required to lower the pressure as needed. Since my pump only pulls the 3.5”hg pressure, I didn’t need the valves.

I’m sort of surprised this two outlet aquarium air pump only draws 3.5 inch Hg for you. Seems sort of underpowered somehow, like there may be a leak! As you didn’t mention any sort of seal, are you sure that air isn’t leaking in where you joined the two different size air hoses?

Also, I am curious as to how much pressure can you get with only one of the air outlets connected?

If you follow and investigate the topic back all the way to it’s original source you’ll find that it was someone elses idea, but I’m sure the originator would have appreciated your thanks.

Since the 3.5”hg is my preferred pressure, I am not that motivated to look for leaks, but I might put some water on that joint where the 2 hoses connect just to see how air tight it is.

With only one air outlet connected I am guessing I would get a pressure similar to a Whisper 10 pump. I originally bought and tried a Whisper 10 and had to return it and buy the Whisper 40 as the 10 was totally inadequate for generating enough pressure to pump with.

I could really see buying a wisper pump and modifying. Thanks guys for all the improvements to modern pumping. I wonder if it is possible to control the pump with a computer via USB, including a controlled relief valve without spending a fortune.

Thanks for reviving this information about converting aquarium air pumps to vacuum. Here’s what I found:

Walmart had 2 Tetra Whisper pumps, both were cheaper than anything at the pet store. I bought both models, the Tetra Whisper 10-30 and the 30-60. I did the conversion on the smaller pump (10-30) and it produced a very weak vacuum, not measurable on my brake bleeder pump gauge. I opened up the larger 30-60 model and did the conversion - the parts were slightly different. The 30-60 has 2 pumps inside the housing. I converted just 1 pump and measured the vacuum - exactly 5” on my gauge. I removed the parts from the other pump inside the 30-60 to save them for future repairs.

So a few of observations:
The brake bleeder gauge may not be very accurate - I have 2 and they show different values at the same vacuum - therefore the search is on for a better quality gauge. The smaller Tetra pump should produce about 5” of vacuum but some units, like the one I purchased, just don’t work very well - so it just depends on the particular pump you get - it might be weak or it might be strong. I found no need to use both ports (pumps) inside the model 30-60 as one side works just fine. The lower the pressure from 5” to 3” I simply added a “T” to the hose and a small valve - open the valve to leak some air and it lowers the total vacuum available. I initially used the plastic air valve that came with the pump. I also tried another I purchased at a pet store. The best small valve came from the plumbing department of Lowe’s - look for drip irrigation supplies and you will find all kinds of fittings that are the same size at the Tetra pump outlet. Finally, I suggest the silicone air hose available at better pet stores (our Walmart did not have it) - the silicone hose does not kink and seals well at each fitting.

How did you get the valve assembly out of the case without damaging the rubber bladder or the white mounting plate? I’ve pried and pulled at the thing, but can’t seem to get it out.