Jump to content

Hot Glass Formula Question


Recommended Posts


Do differant formulas have differant densities?

I ask, if compressed (rolled into a ball), will you get differant reactions?

If a particular color, was less dense, when compressed with glass with more density wouldnt it be squeezed, (the first) forced out the sides ("sandy"). Also more likely to "smear"(gotta go somewhere) across the surface of higher density glass.?


edit: probably would be more (heat sensitive)? less dense easier to heat? or reacts at lower temperature?

editedit: I expect, even if so, at some point (temperature) they would (combine/equal/blend) into the same mass (blob)

but before that?

Editeditedit: edit to the editeditedit

alright, a density example: take a bugger. now roll it around twix yur fingers, c how some jus "disappears"(not,chk that fingernail)while the other rolls into a tight ball.


alright sorry bout the bugger joke. Serious question on the table!

Link to comment
Share on other sites

not so sure rolled in a ball is really in much of a state of compression. and once the various materials have bee melted and made glass I believe density is fairly close with different colors. Its all glass. Now different chemicals in the glass can react at different temperatures or length at temp. To create color variations. Adding or removing oxygen can also create variuos reactions. I think what made up the glass would create most of the variations we see.

Link to comment
Share on other sites

I thought it a good question.

Relative, Galen, relative. (thank you for the response)

Compared to unrolled, there would almost have to be a "differance" of compression.

Density is my question. And I aint got a clue. I would have to question "its all glass", if all things were (completely combined)(or heated past a certain point) would it not a that stage be a single colored "blob". Chemical componentants certainly the (main)(?) reactives.

I saw a (glass man) take a look at the thread and move on. Sooo I'm a guessing, this dog wont hunt.

But "fairly close" densities I would expect, The differances, if subtle, maybe minut.

Minut may be jus enough to "fuzz" the perimeters(edge) of a line. After a much closer inspection than ever before.

I see squeezing edit/pushing/seperationendedit, taking place. and sometimes unicorns.

The amount of competing forces(laws) going on in something as volatile as a marble making operation, I can barely speculate.

allright, I'm wordy and speculating(well past barely)

but looks like (sand)(a chemical component) not mixed or formulated to the degree of surrounding............

in say concrete, density depends on a wide variety of combinations of chemicals and mixing practices. And Bread. and....

thanks for engaging galen.


relative-second cousin to my aunts third

edit: to Mike below, whew, thanks, thats something to chew on.

spaaat, that bubble gum - did you clean your fingers after the first -training aide!?

Link to comment
Share on other sites

"..Do differant formulas have differant densities?.."

Yes, but probably not very significant when it comes to a ~5/8" marble glob on the rollers. I expect at a larger scale, say in a furnace, density (specific gravity) would play a bigger part since heavy sinks and light rises = separation/statification.

With compression and squeezing what might be a bigger factor is the apparent viscosity (resistance to flow). Lower viscosities "flow" better than higher viscosities. Think of trying to roll a ball out of bubble gum (high viscosity) and adding water (lower viscosity). Of the two, the water will be more likely to squeeze out.

Most materials viscosity will change with temperature

Link to comment
Share on other sites

Chemical properties also have a lot to do with it, not all glass has the same specific gravity ie: lead glass being heavier. You'd see this mostly under static conditions like a furnace. Trying to mix/cool glass in a marble size with different properties will probably be more difficult for reasons like COE than anything else mentioned above.

Except for the unicorns. Anything is possible.

Link to comment
Share on other sites

This was discussed before. I wasn't going to jump in. Remember the discussion Rich had about mixing glass. Most glass doesn't mix. One color of glass sticks to another color, but doesn't mix. That's how you get ribbons and patches and swirls. BUT sometimes the glass does mix and a glass man will have to tell you how that happens.

Link to comment
Share on other sites

Glass Density

Here are some words used in science when working with glass density:

Density is mass per unit volume (g/cm3).

Density gradient is a column containing a liquid mixture that undergoes a gradual decrease in density from the bottom level to the top level.

Density meter is an electronic device for measuring density.

Plummet is a sealed, immersible chamber of known volume and density.

Temperature controlled column is an item specifically made to contain density liquid and remain at a constant temperature.

Meaning and use of density:

Density, a fundamental property of glass, varies with changes in composition and thermal history. Density determined either by direct measurement or comparison is suggested if elemental analysis is not available. It is impractical to measure density on glass fragments smaller than two to three millimeters. If two samples of glass can be differentiated by density, they could not have originated from the same source. Further limited discrimination may be possible by doing a density comparison in conjunction with refractive index comparison.

Something to think about:

Glass samples exhibit a range of density values. Density is a function of the chemical composition of the glass and its thermal history. The composition of a glass sample can be measured by a variety of techniques. Thermal history is typically assessed through a measurement of either refractive index or density.

Link to comment
Share on other sites

Not a glass guy but I could see the beige glass squeezing out with pressure, like when the glob hit the screws), IF the strata of beige glass had an appreciably lower apparent viscosity than the strata of glass above and below it. I think differential viscosity (flowability), might be a more significant variable than differential density. Like when you bite into a s’mores, when the marshmallow gets good and gooey.

Link to comment
Share on other sites


got lost

all, properties of the ingredients?

the mix and (mixing) - the more mixed and/or heated the more uniform, less (mixing/heated) differing mixes, differing "vescosities"?

In my line of work, more or less mixing affects "viscosity" and density. Or viscosity affects density, anyway.

seems the properties would have to be differant or it would be a (single) color. It looks like a hotassed glob of glass.

But there is reason to believe that a past manufacturer had a lot of intentional control of that glob.

Taint incidental, and it smeared cause they wanted it to. IMO


after the edit, I couldnt think of nothing, so thats what I said.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...