Years ago I had built a granite coffer. The dimensions reflected that of the great pyramid. Going through a divorce though and it being outside in the back yard I had to deconstruct it. I was wondering if anyone had any other projects like that or any experiences of that type of construction for astral projection purpose?

In terms of a "Viewing chamber", I haven't personally done anything.

I understand Joe McMoneagle got some magnetic shielding material and built a chamber out of that, about 2012.

The guy that brouught Uri Geller out of Israel, Andrei Puharich, did a lot of work with Faraday cages, energised to ground, high positive and high negative potentials (this is very dangerous with the high and low potentials), he found that a grounded Faraday cage worked best for his psi experiments.

I forget the name of the aluminium chamber, again grounded electrically. - EDIT kozyrev mirror thank you elemni.

that as much i know tbh. find wearing an old school steel helmet cuts the noise a little bit while viewing and certain items produce worse results. presumably they have some kind of blocking or distortion effect again introducing rather than reducing it. none them perfect results effects could be psychosomatic really need my big crystal to do any psychic work etc think there is but it pretty small.

Is the effect because it's stone, or because of the sensory deprivation?

Testing with a floatation tank a few times might save you a HUGE amount of time, effort and money!

You also have other means that i believe can induce a higher state, they work for treatment dis-ease:

I did some blind experiments on that Orgone stuff. Children and some people can feel it. No doubt about that. There is clearly something about it. Maybe also good for RV. Never heard about it being tested for RV purpose. I think that is scalar wave energy.
Cheap & easy to make: Alternating layers of isolator and metal (no Aluminium!)
Steel wool and kitchen plastic foil or cotton wadding is cheapest. Box and tins: iside layer: metal, most outer layer: isolator. Also good for energizing water. It gets stronger and stronger over time if you refill and leave a small rest. My blind experiments showed similar taste close to fresh well water from the forest (not the same but also very good). Even direcly after fresh refill from the tab. Everyone was able to taste the difference. blind!
Blankets, Pillows (for female pain!), tins, "helmets", ... -don't store it close to the bed, especially not the footend, desk, etc. or redissemble after use. More layers: stronger.

And here is the context of the Orgone accumulator to the Granite:
Granite contains Feldspar, Quartz and Mica.
Feldspar has an electrical conductivity, Quartz and Mica are isolators.
See also the similarity to the Kozyrev chamber: Aluminium and Air as isolator. But Aluminium has side effects according to Reich. That might explain the partly negative results of Kozyrev, et al.
There is more context. Kozyrev and Reich both cured also psychic diseases. So we have a connection to psychic enhancement. Reich wrote about UFOs and how to take them down with his Cloudbuster which draws energy and which was connected to the water by metal hoses ... Kozyrev and others using K-Mirrors reported on Orbs and UAP over and in their labs.

Reich (and later Prof. Bernd Senf) also used the Orgone Energy to treat accupunkture points.
And here we go back to the Granite... This Maya "helmet" has inlays to treat those points at the back of the head and it is said to have been used for meditation.

These inlays are from Jade which becomes conductive when it gets warm by the body! -Conductor on the inner side.

Hmm, Mayan Artefact or standard pattern Russian steel helmet with all markings removed and my own name and date added as markings.

I know which I'd rather pay for, and I generally don't bother with it anyway. I bought it because it FITTED me. Very important consideration when it comes to helmets.

You can imagine the problems the Maya had, trying to share headgear or have enough of them to go around.

More layers of metal and isolator should have a stronger effect. You could try to make a cover for the helmet with alternating layers of cotton wadding and pulled steel wool. The layers of metal can be thin, as long as they are well seperated from each other. Would cost close to nothing. Steel wool for polishing is available at any hardware store. The metal helmet with its steel inside is perfect for this! You dont need to glue it on. It can be removable, on the outside of the helmet. I am not a sensitive or Viewer, etc., but I would definitely try it if I were. But don't go for 20 layers from the start. Could be too much if you are very sensitive. 3-5 are better for beginners you may add more later. With a nice outer textile and your favorite design pattern. Would also look better...
Made some nice anti-pain pillows this way for my girlfriend -it worked for her.

Hmmm...

I can't quite remember who, might have been Nyiam. Certainly a very good viewer.

They were blindly tasked on viewing a person doing normal remote viewing, and then a person viewing from inside a pyramid. Although I can't recall what kind of pyramid.

Anyway, the 2nd session looked like someone wearing a superman costume. Which could be a indication of super powers, or an indication of somebody with Heroic Idiocy delusions. Possibly both.

WOW. So RV inside a pyramid would eventually be too much and drive one crazy or into exuberance.
That is interesting!
It fits exactly into the findings of Wilhelm Reich. He (or was it Prof. Bernd Senf?) said: "The resolution of the blockage is the solution. Gently, not violently."
This is precisely within the context I mentioned. The "too many layers" above.
I can imagine that. -A big pyramid may be very a powerful tool/ accumulator if it has the right dimensions and material.
And the RV sessions are long so this would be a long exposure time in a strong field.
Reich always started slowly and with shorter exposure times when he used his powerful orgone chamber on patients. It had 10 Layers and had not been disassembled between the uses so it became stronger over time. And it was also in a room with metal-plated walls.
Let me add more context:
Dr. Klaus Dona (all images I am linking here are made by him) reported also about a small stone pyramid which had been found in Guatemala (if I remember correctly it was about 17 cm / 6,7 inches high):
https://www.facebook.com/KlausDona13/posts/this-is-the-only-known-artifact-of-a-pyramid-with-an-eye-inlay-13-steps-and-the-/940604189731278/
there has been also found a stone showing a person holding such a pyramid in both hands -one under and one on the top-
with a hedgear
- a kind of helmet -
connected to a kind of parabolic antenna with another small pyramid where the LNB would be nowdays. See it yourself what he is doing ...

and a helmet with a strange hole has also been found in the same place...

only the dish is missing...

"WOW. So RV inside a pyramid would eventually be too much and drive one crazy or into exuberance."

This has been reported with Kozyrev mirrors IRL. Also the RPG allegory, Call of Cthullu - the more Cthullu Mythos you know, the more insane you grow.

This is why people are recommended to start with shielding and grounding by some energy worker groups, rather than diving straight into Farsensing / Scanning / Farsighting / Remote Viewing.

But hey, it doesn't matter with where you start in life so much as where you end up. :)

"I'll still ask - have you tried the sensory deprivation tanks??"

Nope.