Question for those that stabilize their own

Shaughnessy

Shaughnessy

Joined
Apr 11, 2007
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1,077
So I put my vacuum chamber together today, and besides my neighbors thinking I'm cooking up batches of crystal meth, it was kinda fun. Heres my problem. I can push and hold pressure no prob. Cant get the venturi vac to pull anything that even registers on the gauge. The compressor just runs and runs, and nothing. Its like theres a giant hole in the pot. When I shut it off and open the valve you can hear the pot drawing in air so the vacuum is sucking air out of the pot. So for those that use a similiar set up how long does your venturi vac take to draw down to the 20's? Am I not being patient enough?

The little venturi vacuum block is behind the regulator in the pic, so you can't really see it.

Larry
 

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Why not use the intake side of the compressor to draw the vacuum? Then you can switch to the outlet side of the compressor to pressurize the pot.

I am not familiar with venturi blocks so can't comment on them.

George
 
I have a paint pot and venturi vacuum pump also, and mine pulls to 25" in seconds. The venturi is nothing special, only the harbor freight model for like $20. The gauge should register a vacuum as soon as you start airflow. I push at least 90PSI through mine. Couple things. Why do you have the regulator in the plumbing? Have you tried hooking the venturi up in the other direction to make sure you have not hooked it up backwards? I doubt it is a leak in your pot cause you said it takes and holds pressure.

I pulled every single bit of plumbing off of mine that I did not need except for one line in, tee, pressure gauge, and one valve, and quick disconnect to hook up my venturi or air hose for pressure.

Lots of guys in this forum have suggested that pulling a vacuum using the inlet of their air compressor is not so good for the compressor for a couple reasons. One is the unit was not designed to pull, but to compress. And the other thing is I would not feel safe pulling flammable fumes through the compressor knowing how hot my outlet air temps are. But of course I cannot confirm or deny these claims cause I am not a castmember of mythbusters so...

I just had a random thought. look at the underside of your pot lid and look at the opening that you have the venturi hooked up to. my paint pot has several openings for plumbing, and one of em is restricted to like maybe a pinhole. If you have the vacuum hooked up to that one of course that is gonna cut down on your vacuum flow.
 
Thanks guys for the info. I dont know if I could do it thru the compressor only cuz its got a cage around it and might be hard to rig up. Not sure. I will check what your saying Gixxer. Sounds reasonable. I got the same HF pump ur talking about. Either I got a crack or something is seriously wrong. My compressor was running for like 2-3 minutes with nothing, so I dunno. My configuration has the regulator in there so I can push pressure and vacuum in a single pot. The ball valves isolate each section, to a take the pressure off the gauges. The pic is probably confusing, cuz of the angle.

Thanks guys,
Larry
 
I haven't stabilized yet, but I have the set up done. I have a vacuum pump to a air tank, to a paint pot. The air tank holds a vacuum so if there is any leakage, it will take a lot longer. I can get up to about 25" of vacuum with that whole setup in about 3 minutes.
 
Hey Larry,

Do you register a vacuum with out the chamber? You know, like close the valve and see if you get a vacuum on just the line. If you don't your leak is probably in there some where. It won't take much of a pin hole to just keep sucking and sucking and never build a vacuum up. If you put the palm of your hand over the end of the hose do you get a hickey? Just a few thoughts trying to isolate portions of the system to see where the prob is.

Good luck, Phil
 
Sounds like you're pulling at least some vacuum. Are you sure the guage is reading ok.

Just a thought, Craig
 
To run the venturi, you want the compressor's full power. Run the line from the ball valve to the venturi at full pressure. I suspect you are not getting enough air flow through the venturi block, and only pulling a tiny vacuum. If that is not the trouble, check that the gauges are working right. Maybe the vac gauge is full of resin or something?
Stacy
 
Thanks for your input on this guys.....

Well I think I found part of the problem. Theres a hairline crack in the aluminum block of the venturi pump. I guess Im gonna need to buy another vac. So back to Harbor Freight for another of these, or spend more and get a heavier duty pump?

I like the design idea of adding pressure or pulling the vac and then using the valves to take the load off the gauges.


Heres some pics of the other side and the crack in the block.

Larry
 

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I just set one up today,straight pull from the pot to the vacuum pump,no frills setup.
How long do you guys keep them under vacuum to get full penetration and what kind of stabilizer are you all using.I am using Akryloid B72 dissolved in acetone.
 
Honestly I have not had any problems pulling a vacuum in a timely manner. my setup is pretty darn close to yours, and I have confidence with my setup. I do not think you need a heavier duty pump. You did not mention if any of the openings in your pot lid is the size of a pinhole.

J, I keep my stuff under vacuum for a couple days then check to see if the wood is still floating. That time is dependent on how dense the wood is, and how thick you are mixing the B72 and acetone. Denser or thicker = longer soak.
 
Gixxer the long stem on the inside of the pot....I cut that off. The elbow fitting goes directly onto that and out to the vac pump. Hole is like 3/8ths or so. Well maybe another cheapie at the HF? Its fine to go directly to the tank however you dont want to continously run / cycle your compressor thats why theres a valve in the line.

Larry
 
Got it figured out. I had a bad vac gauge. Exchanged it, and actually I was pulling vac before it just didnt register on the gauge. Now I know I can pull down to between 23-24 and hold it. I also put a little CA over the hairline cracks, just to help in case it starts to leak. No problems so far tho...:D

Anyone get below 23 with one of the little venturi pumps? Thanks again guys for helping me troubleshoot that thing.

-Larry
 
Glad you got your problem sorted out. I am pulling around the same with mine, give or take a swing in either direction for gauge inaccuracy since mine is beat on a little also.
 
If anyone else is interested in the tutorial on this vac pot, send me a PM with your email address and I can send it out to you. The file is a PDF, and about 680K so, its probably too big to go up on the board. Its pretty easy to follow tho, so if you guys want it just let me know.

Larry
 
Shaughnessy said:
If anyone else is interested in the tutorial on this vac pot, send me a PM with your email address and I can send it out to you. The file is a PDF, and about 680K so, its probably too big to go up on the board. Its pretty easy to follow tho, so if you guys want it just let me know.

Larry
Click to expand...

PM Sent!
 
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