My current vacuum source and a little thought on the topic

[Osmosis Vanderwaal]

1. 
   When it comes to vacuum sources for the labf
   
   
   
   When it comes to vacuum sources for the home lab, unfortunately cheap options are hard to come by. If you want an actually good laboratory vacuum pump, expect to shell out $500 for a used piece that is the minimum of good. Most of us home enthusiasts don't have that kind of money. We make due with repurposed;
   1. Rotary vane vacuum pumps, most often used to dry water out of A/C lines and detect leaks. The main problem with this type of pump is that all of the air and gas you vacuum out of a vessel, travels through the pump oil, and degrades the seals and spoils the oil pretty fast. Certain chemicals broke the oil down in 1 run of less than 4 hours. I've killed a couple of cheap ones.
   2. There are diaphragm pumps similar to the rotary vane pumps in size and power consumption. They don't use oil, sonthey don't have that problem, but they don't draw a very strong vacuum. Not enough to be useful
   3. Chinese companies like Vevor make little diaphragm pumps for chemistry. Inside they are basically and aquarium pump and have very little volume clearing ability, but they can just barely muster a usable vacuum on a static load, and they start at about $175
   Here's what I'm currently using, a 2 stage diaphragm pump, plumbed in series. It was about $30 on Amazon, but aliexpress has them for $20. It's ran off of a 24 volt power adaptor I had laying around, but $15 on Amazon will get you a really overpowered one, $10 on aliexpress so, $30-40 I put it on a gadget ( I have a few) and it pulled -28"hg. Water boils at 100°f instead of 212 (37.8C instead of 100) enough to work for most common solvent distillation, vacuum filtering and dessication..just thought I would show a cheap alternative for a piece that goes with a basic kit
   
   

 

[Osmosis Vanderwaal]

I forgot venturi vacuum sources. Some are $300 and up and you have to have running water. They make cheap ones but I'm not sure if they are up to the task or not. Also this pump pulled -23"hg on one side, so it could be used as 2 sources over vacuum also running the second pump online made it 1/10th the volume of a single diaphragm pump. It's whisper quiet.

 

[jessejames122669]

I 3d printed an asperator vacuum pump and have it in line with an electric water pump that recycled water in a bucket. I havent had a chance to use it yet. Its loud. my little oil ac vacuum is pretty much fried. Nitric acid does a number on them

 

[Osmosis Vanderwaal]

Hcl too. Anything really. I have a single diaphragm pumpnthat is basically half of this and its too loud to run at night. This one is also loud if only hooked up to one side, but when you attach the second daiphram, it gets 20 dB quieter

 

[Dr. MMX]

i got vevor's cheapest,, funny that it lasted about half year with using couple times a week. Usually for filtratgion of mmc freebase or vacuum distilation. Probably I am luck

 

[Osmosis Vanderwaal]

I've kept them alive for a while, ,maybe 6 months also, it was a 4 hour distillation that killed one and vacuum distilling *something that was very acidic if I had a really good trap or 3 it would last 5 times as long

 

[Loki12]

I have found that for distilling high boling compounds and using the pump with corrosive or solvents that affect the pump health, it is a better, cleaner and overall more cost-effective idea to buy the cheapest AC vacuum oil pump and once it dies (stops turning on) just trash it and buy a new one. No need for fancy-pantsy pumps with chemically resistant parts, they cost too much, they still require maintaining, parts are sometimes also hard to acquire if you are not a registered individual.

 

[Osmosis Vanderwaal]

I've killed a couple. No parts available for a $60 vevor 1/4 hp 3.5 cfm pump. What I like about these little DC vacuum pumps is, you hook up the other side and it's a compressor. I blew up a kids inflatable cnair last night with this one. Took forever (15 minutes) but these don't move a lt of volume. I thinkmit could air up my tire if I tried

 

[gnbarsh3463_11]

How about machining these parts from teflon? The thing that happens to my oil pump is that the sliding plastic valve inside absorbs solvents and expands, and then gets stuck. It's easy to machine this part out of teflon with home tools (it's literally two plates with springs inside them), but I'm not sure about how well teflon is going to work because it's much softer than whatever material the valve is made out of.
And the metal parts - maybe they can be coated with nickel for corrosion resistance?

 

[Osmosis Vanderwaal]

Both of my rotary vein pumps have Teflon blades, the problem is the oil breaks down and you lose vacuum and there are some tiny valve body holes that tend to get clogged

 

[Labchef]

I wish there is a video showing a vacuum distillation using one of those rotary vane vacuum pump used to degass epoxy.

 

[Osmosis Vanderwaal]

I e burnt up a couple of them. It's really straight forward, how to use them. You hook them up and turn them on, you aught to have a t on it, one side is your vacuum line, the other side is a valve and on top is your gage, you open the valve a little and that's how you control th3 vacuum. The bigg3st problem with them is all ofmthe air you vacuum goesmthroughnthe oil be9fe being expelled. That's OK for hvac or a vacuum chamber, but the life expectancy of the oil could be as low as 1 minute, but 4 hours is my average inciuld g