So my bro is stuck on doing two things and hopefully someone here has some experience in these or knows enough about the chemistry/whatever to know how to do this.

(1) There’s a soy wax candle he is making and would like to have a “frothy” look on top. He has mixed the soy wax with baking (or bicarb?) soda and it’s created the desired frothy-type look on the top of the candle after the wax has set. But when the candle burns, it’s heating the wax, and the soda in the wax is releasing CO2 and the flame dies right down because of the now lack of oxygen around the wick. What could be used instead of baking (or bicarb?) soda?

(2) Trying to cut a glass bottle in half. More precisely, a square glass bottle. How could you cut a glass bottle (scotch/whiskey style) in half? Have tried getting string around the bottle and lighting it, thereby heating the glass, then quickly putting it in cold water, but the best he can get is a wavy break in the glass, up to 1cm wide. How could you break the bottle in half with a straight cut?

I’m not sure of the exact method, but I think you can cut bottles with heated wire.

No guarantees, but I found this:

http://www.ehow.com/how_7676588_make-hot-wire-bottle-cutter.html

Can you tell I was a child in the 1960s?

buffy said:

No guarantees, but I found this:

http://www.ehow.com/how_7676588_make-hot-wire-bottle-cutter.html

Can you tell I was a child in the 1960s?

I seem to remember you could buy an electric one, may have been battery powered.

To make wax look frothy, get and old fashioned egg beater. Melt the wax and then beat until frothy. Keep beating until almost set and then use a spoon to place where it’s needed.

Thanks, I’ve passed on details about the egg beater for frothy soy wax.

Cutting the glass bottle, he has tried a burning string but can’t get a straight line. Not sure the method for using a hot wire (how you could heat the wire and keep it hot long enough while around the bottle?), but thinking this might be a similar thing to the burning string. He said something about a diamond disc (??) on an angle grinder but I’d be concerned the glass would just shatter.

Use a glass cutter…

JTQ said:

Thanks, I’ve passed on details about the egg beater for frothy soy wax.

Cutting the glass bottle, he has tried a burning string but can’t get a straight line. Not sure the method for using a hot wire (how you could heat the wire and keep it hot long enough while around the bottle?), but thinking this might be a similar thing to the burning string. He said something about a diamond disc (??) on an angle grinder but I’d be concerned the glass would just shatter.

That would work. Protect the operator and onlookers from the sharp silica dust. Think silicosis.

Real men use their teeth.

JTQ said:

Thanks, I’ve passed on details about the egg beater for frothy soy wax.

Cutting the glass bottle, he has tried a burning string but can’t get a straight line. Not sure the method for using a hot wire (how you could heat the wire and keep it hot long enough while around the bottle?), but thinking this might be a similar thing to the burning string. He said something about a diamond disc (??) on an angle grinder but I’d be concerned the glass would just shatter.

connect the wire to battery terminals??

(Only to get the caps off beer bottles.)

http://www.instructables.com/id/Want-to-cut-wine-bottles-Build-this-jig/

http://www.instructables.com/id/How-to-use-a-wet-tile-saw-to-cut-glass-bottles/

Michael V said:

JTQ said:

Thanks, I’ve passed on details about the egg beater for frothy soy wax.

Cutting the glass bottle, he has tried a burning string but can’t get a straight line. Not sure the method for using a hot wire (how you could heat the wire and keep it hot long enough while around the bottle?), but thinking this might be a similar thing to the burning string. He said something about a diamond disc (??) on an angle grinder but I’d be concerned the glass would just shatter.

That would work. Protect the operator and onlookers from the sharp silica dust. Think silicosis.

I think the problem is quartz. None of that in glass.

Pull some wire out of an old toaster. Make it short enough and connect to a car battery or such.

It’s crystalline silica dioxide that does the badness. So I guess sibeen isn’t incorrect this time…

morrie said:

Michael V said:

JTQ said:

Thanks, I’ve passed on details about the egg beater for frothy soy wax.

Cutting the glass bottle, he has tried a burning string but can’t get a straight line. Not sure the method for using a hot wire (how you could heat the wire and keep it hot long enough while around the bottle?), but thinking this might be a similar thing to the burning string. He said something about a diamond disc (??) on an angle grinder but I’d be concerned the glass would just shatter.

That would work. Protect the operator and onlookers from the sharp silica dust. Think silicosis.

I think the problem is quartz. None of that in glass.

Sure, that’s the way it seems, but would anyone want to test the theory by breathing glass dust?

“Generation of cristobalite, a particularly toxic form of respirable silica, also occurs during high-temperature industrial processes involving amorphous silica or quartz.” (UpToDate)

Wouldn’t one just love to polish the tiger’s eye gemstone? Cristobalite replacement of crocidolite. Sometimes comes as a blue, partial replacement rock…

Thanks everyone, I’ll pass it on :)

For cutting the glass bottle, I’d take it along to a shop that sells just mirrors & glass. They need to cut glass exactly straight all the time and will have the correct tools for the job.

I used to cut the bottoms off flagons to make little bowls, made hundreds. The method was to score the outside of the bottle, then rotate it over the tip of a flame produced on a small mini-blowtorch affair connected to a small gas cylinder. It would usually brake cleanly in two.

Another method that I’ve read about (but never tried) is to fill the bottle with oil up to the desired level, let the oil settle, and then gently dip a red-hot poker into the oil.