Clay Pit Density Reduction - Just Add Salt (and more water)?

[Boggy Man]

There is something that has been on my mind ever since I watched a video linked to in this thread, especially the part found here! By adding salt to liquid clay, it turns into a thick buttery consistency! So, my question is this:

If you create a low viscosity (runny) mixture of clay and water, pour equal amounts of it into two containers, and add just salt to one to make it very thick and viscous, and add just more dry clay to the other to match the viscosity of the first one, which one would have a lower density/weigh less? Would the increase in density from the addition of salt be less than the increase in density from the addition of more dry clay to create the same viscosity? If so, then having a salt/clay mixture in the claypits could result in something where the models would have less buoyancy, making submersion easier!

Of course, there is the question about whether the salt could cause any eye/skin irritation, and possibly be hard on hair/wardrobe. Of course, if eye/skin irritation from salt was a problem, then no one would swim in the oceans or seas. However, it can be bad for the surrounding vegetation/environment when it spreads outside the pits, and where cleanup occurs.

Just something to think about.

[Fred588]

I think you are confusing density and viscosity. Density is the weight per unit volume. If you increased density the models would have MORE buoyancy.

While I have not experimented with this, I suspect that adding salt would increase the density but probably not as much, for the same effect on buoyancy as increasing the amount of clay. On the other hand, there are many different kinds of clays and I have no idea if salt would have the same effect on them all. For example, some clays absorb water and expand in the process, others do not.

There is something that has been on my mind ever since I watched a video linked to in this thread, especially the part found here! By adding salt to liquid clay, it turns into a thick buttery consistency! So, my question is this:

If you create a low viscosity (runny) mixture of clay and water, pour equal amounts of it into two containers, and add just salt to one to make it very thick and viscous, and add just more dry clay to the other to match the viscosity of the first one, which one would have a lower density/weigh less? Would the increase in density from the addition of salt be less than the increase in density from the addition of more dry clay to create the same viscosity? If so, then having a salt/clay mixture in the claypits could result in something where the models would have less buoyancy, making submersion easier!

Of course, there is the question about whether the salt could cause any eye/skin irritation, and possibly be hard on hair/wardrobe. Of course, if eye/skin irritation from salt was a problem, then no one would swim in the oceans or seas. However, it can be bad for the surrounding vegetation/environment when it spreads outside the pits, and where cleanup occurs.

Just something to think about.

[dlodoski]

There is something that has been on my mind ever since I watched a video linked to in this thread, especially the part found here! By adding salt to liquid clay, it turns into a thick buttery consistency! So, my question is this:

If you create a low viscosity (runny) mixture of clay and water, pour equal amounts of it into two containers, and add just salt to one to make it very thick and viscous, and add just more dry clay to the other to match the viscosity of the first one, which one would have a lower density/weigh less? Would the increase in density from the addition of salt be less than the increase in density from the addition of more dry clay to create the same viscosity? If so, then having a salt/clay mixture in the claypits could result in something where the models would have less buoyancy, making submersion easier!

Of course, there is the question about whether the salt could cause any eye/skin irritation, and possibly be hard on hair/wardrobe. Of course, if eye/skin irritation from salt was a problem, then no one would swim in the oceans or seas. However, it can be bad for the surrounding vegetation/environment when it spreads outside the pits, and where cleanup occurs.

Just something to think about.

If I didn't have some other tricks to try this year, I would definitely consider running the experiment.

I'm presuming that different clays would respond differently to the salt. If I had to throw a mental dart at it, I would think that clays with higher plasticity would thicken up faster. But it's conceivable that you could reduce density by a measure able/practical amount.

Thank you for the tip.

[Fred588]

This is far from definitive but I found the following, which bears somewhat on this question:

http://cigmat.cive.uh.edu/sites/cigmat/ ... 13/8_2.pdf

The above reports on a research report on, among several things, the effects of salt on the viscosity of bentonite drilling mud. Bentonite is a type of swelling clay and is the kind of clay used at Studio 588. [There are many other kinds of clay and these might behave differently. ] The study involved what is described as a 6 percent drilling mud, which is a good deal thinner (less viscous) than what would be used in a quicksasnd scene, and the salt level was not extremely high. The result, however, was reported as a DECREASE in viscosity. That means the mud is thinner, not what we want.

[nachtjaeger]

I wonder what effect Sodium polyacrylate (the active ingredient in "Gelly Baff") would have on the viscosity of a high-water-content (and hence lower density) clay slurry?

It seems to me that the ideal "fantasy" quicksand would have both low density (to make a human neutrally buoyant) and high viscosity (to make for thickness and nice struggles.) Some type of adhesive quality (like tar, for example) might be desirable also, for that feeling of being sucked down.

This may sound perverse (okay, not on this forum) but I have been curious what a real struggle would look like in a substance that was at once thick, sticky, and less dense than the human body.

[Fred588]

I am no chemist but low densityand high viscosity pretty much means a very large molecule, and that means organic, and that probably means biodegradable at best and toxic at worst.

I wonder what effect Sodium polyacrylate (the active ingredient in "Gelly Baff") would have on the viscosity of a high-water-content (and hence lower density) clay slurry?

It seems to me that the ideal "fantasy" quicksand would have both low density (to make a human neutrally buoyant) and high viscosity (to make for thickness and nice struggles.) Some type of adhesive quality (like tar, for example) might be desirable also, for that feeling of being sucked down.

This may sound perverse (okay, not on this forum) but I have been curious what a real struggle would look like in a substance that was at once thick, sticky, and less dense than the human body.

[kham]

Bunker C / Crude oil would be the first liquid that comes to mind. All of that, and a nasty way to drown.

[Fred588]

What occurs to me is molasses, but its expensive, biodegradable, and edible to ants.

[Fred588]

Also honey or sugar syrup. More or less the same thing as molasses.

[Boggy Man]

This is far from definitive but I found the following, which bears somewhat on this question:

http://cigmat.cive.uh.edu/sites/cigmat/ ... 13/8_2.pdf

The above reports on a research report on, among several things, the effects of salt on the viscosity of bentonite drilling mud. Bentonite is a type of swelling clay and is the kind of clay used at Studio 588. [There are many other kinds of clay and these might behave differently. ] The study involved what is described as a 6 percent drilling mud, which is a good deal thinner (less viscous) than what would be used in a quicksasnd scene, and the salt level was not extremely high. The result, however, was reported as a DECREASE in viscosity. That means the mud is thinner, not what we want.

So, it looks like the addition of salt to different types of clay can yield different, and even opposing, results, in terms of viscosity change. Unlike bentonite clay, which seems to become more fluid (less viscous) when salt is added, the clay sediment in the video I linked to earlier clearly became more viscous (thicker) when salt was added. So, it would require some experimentation to determine which clays work, and are best, for using salt as a thickening agent for minimum increase in density with a given increase in viscosity. Having a real thick clay with the lower density of runnier clay is definitely something that would make sinking/submersions easier.

Upon further investigation, it already looks like bentonite, which is already being used, already swells up nicely on its own (but salt destroys that). But, perhaps other clays that do swell in the presence of salt water could provide variations in some characteristics from bentonite. Only experimentation can tell.

I wonder what effect Sodium polyacrylate (the active ingredient in "Gelly Baff") would have on the viscosity of a high-water-content (and hence lower density) clay slurry?

I have wondered about other permanent (non-decomposing) alternatives, and apparently sodium polyacrylate doesn't break down, unless in the presence of ions. But, although it is said to be non-toxic, it can be irritating to skin, mucous membranes, and eyes, due to its water absorbing qualities, especially in dry form (like from residue left on skin).