Vacuum chamber and plastic for lid?

[Onoff]

hmm... you could pump water through a venture and use the suction from that?

I've never used one but the guys on the bio diesel foum use them to suck methanol into their reactors... can't remember the numbers but they can get a hell of a vacuum going

I did suggest using a mains tap to create a vacuum...

 

[Kram]

Ordered the vac pump. Vevor currently have a £6 off fathers day voucher, so it was £38

However I might try plaster with the hand pump today. Need to work out how much plaster to use first.

 

[Onoff]

Working on the life's too short basis I just bought one of £38 pumps too!

I'll go get those couple of gas cylinders at the weekend and try and make a concerted effort to start / finish a furnace like yours.

 

[Kram]

Im trying to work out what fittings we need, as the listing only states 1/4". We think they might be SAE, which means 7/16 UNF 20tpi thread.

@daedalusminos do you know what yours uses?

My pump is shipped but looks like snail mail with the tracking number not recognised

 

[Onoff]

My pump is shipped but looks like snail mail with the tracking number not recognised

Same here. Says try again tomomorrow.

 

[daedalusminos]

@daedalusminos do you know what yours uses?

Yes I'd say 7/16x20TPI....measures up at 10.8mm and 5.08 for 4 threads

 

[Onoff]

Posting here as an fyi. Looks to be a JIC-4 fitting. Correct me if I'm wrong:

 

[knighty]

if you need fittings / a hose for it

just just some refrigeration hoses on ebay and cut one end off - fit that end to the chamber with a jubilee clip?

you can get hoses with a little valve built in, will make it easy for you to seal the chamber from the pump :-)

 

[Maker]

Lpg is gas at STP where as Im thinking of say, alcohols/solvents which would liquify as soon as they hit the low pressure side.

The right way to do it is with a cold trap, like this:


It's submerged in something cold and anything volatile will condense/freeze before it makes it to the pump. Of course you do need an easy supply of liquid nitrogen or dry ice, I'm not sure if it would be worth bothering with using regular ice.

I've just had a look on eBay, you can usually get Chinese-made lab glass for next to nothing, but they don't seem to do cold traps.

 

[Onoff]

My vac pump arrived too. @Kram those two right angled fittings I have fit perfectly. One is yours when I see you. Nominal OD on the barbs is 6.8mm:

 

[Kram]

Filled with oil, put it against my manual vac pump, to use the gauge of that, instantly pulls 28 inchesHg, but I assume the manual is leaky - Ive never had it past that. I'll need to add a vac gauge somewhere on chamber or pump.

Should I fit some kind of filter on the vac inlet? Stop particles getting sucked in.

The second note on label, about water vapour.. is it generally ok to vacuum water vapour below 40c?
I guess that rules out my idea of vacuum drying clothes and wet things? Be a bit more efficient than tumble drying in winter?

Pump is 85L/min FAD, say 1 litre of water makes 1600 litres of vapour.
At 8.5L/minute it would be 3 hours per litre. About 0.6kw/h..

 

[daedalusminos]

Should I fit some kind of filter on the vac inlet? Stop particles getting sucked in

Yes, one of those little finger filters - will also help restrict airflow when venting

Edit: This sort of thing...

 

[Kram]

Ah I guess thats a good idea after a vent valve. I ment an inline type, similar to a compressed air filter, to stop any particles from inside chamber getting to the pump.
This came up on amazon, not sure what the metal body is for?

https://www.amazon.co.uk/dp/B07ZKS59HX/

 

[Kram]

First proper test. Tomorrow I will try doing the plaster, as Im going out soon.

Waiting on a few amazons, inline filter and a new gauge.
https://www.amazon.co.uk/dp/B01HQF0H0Y/ was £4, now silly price. They have a couple of others.

The amazon I linked above, got a cheap one for £3. Turns out it is a pnuematic venturi vacuum generator, much like @Onoff 's suggestion. Air is more practical (for me), so might be useful. A bit of effort pulling the compressor out though!

 

[Lazurus]

Those are the same pumps as I have been using for a couple of years. If using in the workshop get an exhaust filter as they can pump out a lot of oil vapour. Use mine on Polyester casting resin, and vacuum chuck on the lathe.

 

[Kram]

My video shows some smoke/vapour, it doesnt appear unless I have the chamber connected, so it might be a chemical gassing from the rubber seals of chamber. What do you think?

 

[Onoff]

First proper test. Tomorrow I will try doing the plaster, as Im going out soon.

Waiting on a few amazons, inline filter and a new gauge.
https://www.amazon.co.uk/dp/B01HQF0H0Y/ was £4, now silly price. They have a couple of others.

The amazon I linked above, got a cheap one for £3. Turns out it is a pnuematic venturi vacuum generator, much like @Onoff 's suggestion. Air is more practical (for me), so might be useful. A bit of effort pulling the compressor out though!

What's the clear pot with the black lid? Water trap?

 

[Kram]

Thats what I'll be using it for. Came with brake bleeder, theres a short bit of hose to go inside and stays submerged to prevent air getting sucked back.

 

[Onoff]

Rather than using the rubber sheet (?), is there any mileage in 3D printing a TPU ring gasket? Thinking less rubber to de-gas and make "smoke", if indeed that's what it is. Sized for that particular CHS of course.

 

[daedalusminos]

I think the 'smoke' from the exhaust is oil or water vapour - don't worry about it too much.

Definitely get a new gauge - a vented oil filled is what you want (I assume that's the only reason you've got your hand pump still plumbed in) and simplify your plumbing. My set-up has the gauge and ball valves (very handy) as one assembly then just a single hose to the pump.