Thread: vacuum chamber

Just a thought here but what about using pvc pipe as a chamber ? You don't have to watch the process do you ? Threaded cap on 1 end,a tee for a valve and vacuum hook up, and if you made it specific for the job it would cut down on the amount of juice needed ? Sorry I didn't watch the vids and just a brain fart here.

Originally Posted by 10Pups

Just a thought here but what about using pvc pipe as a chamber ? You don't have to watch the process do you ? Threaded cap on 1 end,a tee for a valve and vacuum hook up, and if you made it specific for the job it would cut down on the amount of juice needed ? Sorry I didn't watch the vids and just a brain fart here.

I think you have a great Idea,would deff use Schedual 80,getting a 100% seal might be a challange but with some gaskets, maybe doable.

I think that the seal would be no problem but just thought that you better check that the solution won't react with PVC.

Originally Posted by 10Pups

Just a thought here but what about using pvc pipe as a chamber ? You don't have to watch the process do you ? Threaded cap on 1 end,a tee for a valve and vacuum hook up, and if you made it specific for the job it would cut down on the amount of juice needed ? Sorry I didn't watch the vids and just a brain fart here.

the problem with PVC is brittle failure. it may be able to handle the pressure under perfect conditions but a knock or bump under pressure can set it off then it shatters into sharp bits which go flying. better to use a plastic with a more forgiving failure mode like abs.

All good points,seems like thick wall Plexi is the material of choice.

Kennedycustomcalls (source for --90) uses plastic pipe for manifolds (multiple chambers, same vacuum source) and for overflow chambers. Check out his website - kennedycustomcalls.com.
I want to be able to see what is going on in the chamber, so I will go with glass. The amount of liquid has to completely cover the wood as it is absorbed, and I want to be able to monitor if the foam is getting too close to the line to the pump. Pixel, I'd suggest you include a separate overflow chamber in your Mason jar setup. Could be a one quart mason jar, with a couple inches of water in the bottom. The incoming line should extend under the water, and the outgoing line to the pump be at the top of the jar - this info comes from Geezer, who worked with vacuum chambers in his work life.
Really enjoying this thread. Good luck, everyone. I will have my setup working in July.

I also think the visual is important,the bubbling in my test pces lasted about an hr (you have to see it) slowley let down the vac and the fluid level dropped about an 1/8 inch proving that the wood fibers had taken in the poly.
Now will wait a few days and cut them apart to see what we shall see,The process really darkens the wood which to me is a good thing.

Still dinking around with this,I made a system like Glens,The woods were 1.5 x 1in. rounds,Bubinga,Gabon Ebony,Malaysian Blackwood.
Wgt ea pce before the process and after two days in the hot sun,105 degs.each pce took in about one Gm. of wipe on poly.
Since the wood fibers are microscopic in nature,is 1 Gm alot?? No clue.
I turned a half in. off ea pce,They deff turn differant,no chips, just very fine sawdust.
To be honest,am not sure what I Did,but the wood is without question differant.

Originally Posted by bridger

it's an older one, from a thrift store. it has a rubber seal, though, and I see what you mean- there's nothing to keep the gasket from being sucked in. drat.

last night I spent a couple of hours making a retainer ring for the gasket that would spread the gasket tighter the harder the vacuum. made it from mdf. came out this am. and gave it a quick coat of shellac. while it was drying, I thought... am I overthinking this? grabbed the pressure cooker, hooked it up to the vacuum pump and plugged it in. after it pulled down for 30 seconds or so, I could no longer budge the handle. pulled the plug and after 5 minutes or so I could start to move it. I think I don't need the retainer.....

my vac pump is a compressor pump from some old heavy duty fridge or freezer. one advantage of using these is that you can hook it up and just leave it running all night if necessary. it maxes out around 25-30 inches of mercury (12-15 psi) plenty for this process and safe for the chamber. the pump will hold vacuum for a couple of hours, so the leakage is mostly from the pressure cooker. no matter, I'll just leave it running for the time I expect the resin takes to gel.

now to test if the japan drier will kick off a good short oil varnish sans oxygen.

One of the warnings from several sites about vacuum stabilizing is that it is important not to shut off the vacuum pump while the system is holding vacuum - in other words, there need to be a valve between the pump and the tank, which is closed before turning off the pump. FYI .
Pixel - with unspalted wood, your will probably not get a lot of penetration, so my guess is that the the amount of poly you got on the samples you used is about right. The other possibility is to switch to pressure after you vacuum - Randydancer did an experiment with poly and just pressure some time back - I turned several brushes with the wood, and it seemed to have good penetration - most of the wood was not spalted.
Bridger - Your system sounds cool - I like the "make do with what you can find" approach. Let us know how the drying process goes.