# Vacuum Chamber/pump



## LittleBear (Mar 24, 2012)

My experiences:

Decided I wanted a vacuum chamber and pump to try stabilizing soft, panky, half rotten spalted, wood for pens, knife blanks, boxes etc. 

Since I was reluctant to spend much cash without trying the process first I decided to try the DIY refrigerator compressor conversion rout. 

Scored a very rusty compressor from an old refrigerator, to my surprise when I plugged it in it worked. Great had a working pump all I needed was a chamber. 









Even though I had read many warnings about the dangers of flying glass and imploding chambers I decided to try a mason jar chamber, after all I'd seen a few photos of purportedly working ones, had all the fittings and tubing I'd need so I attached them to th lid and mine worked too... for awhile at least&#8230; wasn't there when it imploded, messy and I wouldn't have wanted to have been close when it happened. Ok so glass was out, after a little rummaging around I unearthed the heavy stainless steel camping cook pot I'm still using, the metal lid held up to the pressure but I couldn't see in, from reading I new what I wanted was a ½" thick piece of Plexiglas but having a stubborn streak I shattered, sucked down, and broke an assortment of options from a safe distance before admitting that it was time to make my first purchase a 12" x 12" x ½" sheet clear sheet, add a home made gasket and I was in business. 

My next purchase was a gauge, turned out my rusty glass crushing refrigerator pump was capable of -28.5 inches of mercury (in/hg) at <100 feet above sea level. 

I then started trying out different stabilizing solutions/methods, several work quite well, but what became apparent was that even though -28.5 at my altitude was ok for many projects it wasn't quite enough for others, I needed at least the recommended -29 in/hg or better yet as close to -29.929 on the gage as I could get. At sea level under normal atmospheric conditions absolute pressure is approx. 14.7 psi and one inch of mercury = 0.491161 psi (14.7 psi divided by 0.491161 psi = -29.929 at sea level).

So what's the difference between -28.5 and -29.9 when evacuating air from wood?
Tied off glove at 0 in/hg









28.5 in/hg (less than 100 feet above sea leavel)









29.6









29.8









29.9









Currently using the U.S. General 2 stage pump in the photos, purchased from Harbor Freight for $154.99 - a 20% coupon, by all accounts the cheaper $104.99 Harbor Freight also works but...


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## Sean (Nov 17, 2011)

Interesting, don't know much about it but it looks like your well into a cool experiment.

I'm also glad that after reading the title of the thread I didn't have to hide it.


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## LittleBear (Mar 24, 2012)

Sean said:


> ...I'm also glad that after reading the title of the thread I didn't have to hide it.


Ok, glad I didn't call it "My Vacuum Pump Experience"

Which brings up a point about chamber size, the larger the chamber the stronger it has to be, the pool cue turning forums are full of people collapsing 8" and 10" PVC pipes with converted refrigerator compressors, most of their DIY tutorials use sections of the type of pipe intended for high pressure water mains which apparently is a bit stronger than a large PVC drain pipe.


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## Jakerock (Mar 8, 2012)

What type of stabilizing solution are you going to use?


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## treefork (Feb 1, 2010)




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## LittleBear (Mar 24, 2012)

Have tried the following:
Resinol 90c/Permabond 90c, great but for the price and hard to get reliably, oh lots of people sell it, or what they claim be it on-line but you never really know what you are actually getting, its shelf life etc. Would be my preference if I could find a reliable source for under $150 a gallon.
Ultraseal, again works but...

Lacquer, didn't work
Polyurethane, didn't work
Minwax Wood Hardener, didn't work beyond surface
PC-Petrifier, better bot still no.
Problem with the last 4 is that they contain solvents which boil off even faster under vacuum

Currently use Cactus Juice, works I like it because of; price, reliability, 6 month shelf life once activator is added, heat activated (note, does not dry it activates like and epoxy). Bottom line easy to get best bang for the buck. Have used it on two slingshots so far, Phoenix and Twig.


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## Jakerock (Mar 8, 2012)

Thank you very much for sharing that information! Is stabilizing wood something you ONLY do to wood that might be structurally comprised?


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## MAV (Mar 18, 2012)

Wow, it gets more complex.
I did knife handle stabilizing a long time ago. A open grain wood will suck it up, a dense wood not as much. A oily wood wont take as much. To stabilize a oily wood you need to put it in your chamber with a degrease solvent like MEK to get the oil out, maybe several times. Then it will take the stabilizer deeper. Denser wood takes more time and the vacuum/pressure, vacuum/pressure helps. One thing is for sure its better then a brush coat! Cant go wrong.

Mark


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## LittleBear (Mar 24, 2012)

Jakerock said:


> ... Is stabilizing wood something you ONLY do to wood that might be structurally comprised?


No you can do all sorts of interesting things, prevent warping, dye it, in some cases make it even harder an/or stronger. On my Twig slingshot the wood was in good condition it just wasn't strong enough for a slingshot so I took a chance and it worked, on the Phoenix I needed to harden the soft areas but also added black dye.

Stabalizing can refer to a number of different processes done for different reasons.

My primary goal is to infuse as much acrylic resin as deep as possible into soft, punky, half rotted otherwise useless wood with "character" or on burl wood so that it can be turned on a lathe without flying apart, or be hard enough for a knife handle, jewelry box, etc. Pool cue turners use it to prevent the wood from warping, for those wonderfully straight cues that will never warp, even in the dampest dingiest tropical air pool hall.

Where once there was water, sap, and oil when dry there is air, evacuate as much of that air as possible while it is submerged in a resin and then let the air back into the chamber it replaces that air with liquid acrylic resin, catalyze that resin (not dry or evaporate) and you have a hard acrylic & wood composite material. Note; it will not fill larger voids in the wood, or as noted by MAV if there is oil instead of air it can't be replaced with acrylic, similarly if the wood is so dense that the resin can't flow in there will be little or no change either.

Results vary but if the wood is dry and porous, with strong intact fibers the resulting compost can be as strong as any fiber glass it just has wood fiber instead of glass fibers, as Capnjoe called it in another post "forever material." If the wood is porous but without a sufficient amount of intact fibers it can be hard but brittle, and as indicated above if it's not porous nothing much happens.

I also add reactive chemical dyes to the resin, as an example I added black while stabilizing the blanks to this pen, you can see that the black resin flowed to the porous sections while the hard dense portions retain all or more of their original color.








Other stabilizing processes and/or solutions can add preservatives, oils, dyes only, or like PEG water soluble plastics.


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## LittleBear (Mar 24, 2012)

Sorry for the double post but here's before and after photos of stabilizing with black dye.


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## Jakerock (Mar 8, 2012)

Thank you very much for the explanation of what is possible here. I had no idea that this could be done, especially outside of a highly technical process.
Getting the different color dyes in there is fantastic. For me, the most beautiful natural forks are made more beautiful by the effects of decomposition, and this of course compromises the integrity of the wood. Having this process available makes the best of all worlds for slingshot building. Very cool, and thanks again for the answer.


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## WILD BILL (Jan 26, 2012)

Great information!

I appreciate your time and the showing of the beautiful results

Bill


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## MAV (Mar 18, 2012)

A pic is worth a 1000 words. Very nice results, great job!


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