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 Post subject: How much pressure is recommended for oiling Emeralds?
PostPosted: Tue Jul 16, 2019 11:51 am 
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Location: Tampa, Florida
Hi guys, I have an Emerald that would not fully absorb Cedar oil into all of it's cracks using just a vacuum chamber and a hotplate. I've had this problem before with a much larger stone and we sent it to a friend who fixed it with a pressure chamber. Does anybody know how much pressure is needed?


I've been looking for a machine for a little while now off and on. One of the first people that I found selling a machine specifically for oiling Emerald was in India so I looked for an American supplier instead. The only person I could find that was in the US didn't list prices on his site and asked for all of this personal information "to make sure you were a serious buyer". After reluctantly complying with these strange conditions and talking back and forth, a few days went by and I didn't hear anything. I asked him if he could sell me a machine once again and he responded with, "you would have to look elsewhere..." :roll:

To make matters more annoying, I was warned not to do business with him when I brought his name up with someone I work with. Apparently he had attempted to make faceting machines that could also facet Diamond but they didn't work. So he was saying that his machine for oiling Emeralds might be in the same boat and be engineered wrong. He was probably right considering he was unwilling to sell me one. Watch out for Ted Themelis everybody- guy is a mad scientist.

So now I'm tasked with either building a machine or finding a supplier that produces similar machines but for other lab purposes.


Does anybody have any experience with using a pressure chamber to oil Emeralds? What level of pressure do you use???

Themelis was saying 3800 PSI on his website but that seems as overkill as possible. Wouldn't that crush the stone???


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 Post subject: Re: How much pressure is recommended for oiling Emeralds?
PostPosted: Tue Jul 16, 2019 7:18 pm 
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Joined: Thu May 12, 2016 2:18 am
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In Israel they use a simple hand pump for both pressure and vacuum. It is what most people there use. It sells for between $1,200 to $1,500 for a heater, pump, vessel. Vacuum goes to about -.8 bar pressure to about +2 bar.

I have built a similar machine for my own use. Mine goes to vacuum about -.8 BAR and pressure to about +3 BAR (40 psi) . When heated to between 180 -200 degrees, either oil, or opticon works well at these specs for most stones.

My vessel should actually hold more much more pressure, but I have never bothered to get a better pump. I have been thinking of getting an electric pump so I can increase pressure.

The important things are:

Make sure the fracture you are filling reaches the surface, either directly, or through a another connecting fracture. Make sure all fractures are clean, and free of obstructions. I have found that soaking in Acetone works well.

Heat the stone and the oil under vacuum. The stone and the oil should be heated together to avoid thermal shock, but the stone must not be in the oil. This keeps air pressure from creating bubbles and blocking the oil penetration into the fractures. Then you must drop the stone into the oil without losing the vacuum. To do this I use a wire basket, and magnet system built into my vessel design.

At one time, I was looking to buy a machine that did pressures up to 2500 psi. The one sold in India does do this. They quoted me $2,500 shipped. If I were doing a lot of low quality, highly fractured Emerald, or Rubellite stones this might be worthwhile. But I don't do too much of that kind of clarity enhancement currently. For all but type III stones I find that the clarity enhanced disclosure lowers perceived value more that the visible inclusion. For better quality type III stones my setup works great.

Here is a picture of my current setup.


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 Post subject: Re: How much pressure is recommended for oiling Emeralds?
PostPosted: Wed Jul 17, 2019 10:51 am 
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Location: Tampa, Florida
Thank you so much for your reply! Your setup looks great. Wish I could get one just like it. $2500 for 2500 PSI is a steal considering I just got quoted $7,500 for a machine that caps at 130 PSI.


I'm not sure why the machine I found is so expensive, although it looks really professional and modern. Hopefully I can find a better option but for now I'm thinking I'm just going to send the stone to someone who already has a pressure chamber. I had no idea the machines were this expensive and difficult to find.


Does anybody have any suggestions on a source for this technology?


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 Post subject: Re: How much pressure is recommended for oiling Emeralds?
PostPosted: Wed Jul 17, 2019 11:49 am 
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Location: Tampa, Florida
I'm seeing that some people are using paint sprayer pots converted into pressure chambers for casting resin. Hopefully I can get some results for a much less expensive system. If you only need 40 PSI for finer stone, then I think I'm good!

What do you think of this? I can just set it on top of a hotplate.


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 Post subject: Re: How much pressure is recommended for oiling Emeralds?
PostPosted: Wed Jul 17, 2019 8:16 pm 
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Stephen,
I did a small run of my vessels so I have a few extras. I would be happy to provide you one if you cover my costs. It will be under $100. You can use a hot pad, and buy a pump directly from the manufacturer. My guess is that you will end up with a fully functioning 100 psi vacuum and pressure system for about $250.

Let me know if you are interested.

Steve


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 Post subject: Re: How much pressure is recommended for oiling Emeralds?
PostPosted: Thu Jul 18, 2019 5:45 pm 
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What does the vessel look like? I am very interested. Want to finish oiling this stone.


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 Post subject: Re: How much pressure is recommended for oiling Emeralds?
PostPosted: Thu Jul 18, 2019 8:17 pm 
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Steven Weintraub Jr wrote:
What does the vessel look like? I am very interested. Want to finish oiling this stone.


It is the C&C aluminum container that is sitting on top of the digital hot plate in the picture I posted earlier in this thread. If you look to the side you can see the wire basket, and the magnet as well as a couple of the extra vessels.


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