Vacuum chamber and plastic for lid?

[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.

 

[Onoff]

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

It's raining today

 

[DAPPH]

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.

View attachment 352520

Life's too short to stuff an olive , so is making your gasket ring , you're over thinking a simple solution .

Remember KISS ???
Simply stick the tube to a flat plate using " Bosticks Sticks like Shi* " cartridge gun glue , gluing up the tubes rim & run a thicker bead round the outer edge of the tube , clamp it in place with F clamps till it cures in 24 hr .

For the top get whatever you are going to use for the lid put the evacuation holes & any union threading's in it
For the lid ... Stick a large square of sticky backed plasticto cover the top plate wrinkle free , run a thick ring of " Sticks like " round the rim of the tube , invert the tube to sit on the flat top of whatever lid you want on it , again run a thicker bead round the outside & clamp up for 24 hrs .

Assemble & test ?
Vacuum alone will pull the ends down onto the rims , peel the sticky plastic off or leave on.

Once the vacuum is broken the pieces will part easily enough .

 

[Onoff]

Life's too short to stuff an olive , so is making your gasket ring , you're over thinking a simple solution .

Remember KISS ???
Simply stick the tube to a flat plate using " Bosticks Sticks like Shi* " cartridge gun glue , gluing up the tubes rim & run a thicker bead round the outer edge of the tube , clamp it in place with F clamps till it cures in 24 hr .

For the top get whatever you are going to use for the lid put the evacuation holes & any union threading's in it
For the lid ... Stick a large square of sticky backed plasticto cover the top plate wrinkle free , run a thick ring of " Sticks like " round the rim of the tube , invert the tube to sit on the flat top of whatever lid you want on it , again run a thicker bead round the outside & clamp up for 24 hrs .

Assemble & test ?
Vacuum alone will pull the ends down onto the rims , peel the sticky plastic off or leave on.

Once the vacuum is broken the pieces will part easily enough .

Sorry, who's over thinking things?

 

[Kram]

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.

View attachment 352520

Yes that would be great if you can.
Not raining, sunny here today

@DAPPH cartridge sealant would work, its messy, takes 24h and needs to be removable for storage. I dont want to get any glue solvent on the acrylic lid.

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.

This should be here soon, should be adequate? Whats the advantage of vented, oil filled?

G1/4in Pressure Gauge 0‑14psi Air Gauge Instrument for Vacuum Pump : Amazon.co.uk: DIY & Tools

G1/4in Pressure Gauge 0‑14psi Air Gauge Instrument for Vacuum Pump : Amazon.co.uk: DIY & Tools

www.amazon.co.uk

Are they standard plumbing ball valves?

 

[Onoff]

@Kram knock me up a sketch of the profile you think and tell me the OD and ID of that chamber you turned up.

 

[daedalusminos]

Whats the advantage of vented, oil filled?

Shock dampening from the pressure pulses leading to better accuracy and longevity... especially on cyclic applications.

 

[Kram]

@Kram knock me up a sketch of the profile you think and tell me the OD and ID of that chamber you turned up.

128.5mm ID, 139.15mm OD. Profile looks good and you probably know better than me for rest of sizes

 

[daedalusminos]

A nice soft silicone for the gasket will be ideal...that way the seal will improve under higher vacuum.
Not sure FDM printing a seal is a good idea - it's potentially full of holes!

 

[Onoff]

A nice soft silicone for the gasket will be ideal...that way the seal will improve under higher vacuum.
Not sure FDM printing a seal is a good idea - it's potentially full of holes!

Well it's got a "skin" all round it with whatever percentage infill.

We have to try so we know!

 

[Kram]

I guess the print path could be important? If it loops the circumference may be better than radially outwards. One print groove crossing the seal instead of many. I know nothing about printing, that may not work.

 

[Onoff]

I guess the print path could be important? If it loops the circumference may be better than radially outwards. One print groove crossing the seal instead of many. I know nothing about printing, that may not work.

Laddo is out on the lash or something. Will have to wait until tomorrow.

 

[graffian]

I used to seal bags and chambers with takky tape.
Well I didn't waste the expensive takky tape, I used some sort of
builders[?] mastic tape I found amongst the **** a previous owner had
left in a car.

 

[Onoff]

tape I found amongst the **** a previous owner had
left in a car.

I found a Dire Straits tape under the back seat of my first Capri.....

(Along with an earring and condom wrapper).

Actually would a femidom work? The chamber is circa 200mm dia, sounds about right from my experience...

 

[Onoff]

Printing a test gasket in TPU. If it doesn't work at least we tried. 5% infill to ensure "squishiness".

A super boring video clip. Should be done in 3 hours:

https://flic.kr/p/2nu54Lv