how long

[Jeanne]

Hi there,

I am very new in lampworking and I would like to know how long does it take for the glass rods to melt ? ( in minutes ) What is the difference between soft glass and hard glass??

Thanks

Jeanne

[Redhotsal]

Sorry to be a little pedantic - but that's a bit of a "how long is a piece of string" question! It depends on the torch that you're using, the fuel, the type of glass rod you're putting in the flame and where you are putting the rod into the flame!

Most people start off with a hothead torch - this is made of brass and usually runs on either a special fuel called Mapp gas or standard propane. If you are holding the glass a couple of inches above the face of the torch then I would expect soft glass to start to melt in a matter of seconds - not minutes. Maybe 10-15 seconds?

If you are using a dual fuel torch - such as a Bobcat or a Minor burner, which runs on propane and oxygen then this time will be less - probably around half the time.

It does make a difference as to which glass you're using. Soft opaques - such as White Effetre will melt much quicker than an Effetre transparent such as cobalt. Effetre is softer than Bullseye, for example so you will see a difference between manufacturers as well as the individual colours.

There is a huge difference between soft glass, which is commonly known as Soda glass and hard glass which is commonly known as Borosilicate (or sometimes Pyrex).

This glass has added Borax to it which makes it much harder physically (and is usually the glass of choice for scientific glasswear). It is also harder to melt as the melting temperature is much higher than that of soda glass. Many torches will not be able to melt Borosilicate very easily - you'll be in for a long wait trying to melt this on a hothead as I doubt the torch will get hot enough to melt it. You'll have a similar wait with a dual fuel torch if your oxygen source is low pressure (such as a single oxycon). It is rare for beginners to start off on borosilicate then, because of this increased demand for oxygen. The oxygen will make the propane burn hotter so that it reaches a temperature which will successfully melt the borosilicate.

[MadelineBunyan]

beat me to it sal! I'll post what I already wrote anyway!

the how long question varies depending on what type of torch you have, how you have it set up, the type and thickness of the glass and also the colour.

hard glass and soft glass however I can answer.

soft glass is the type most of the glass beads shown on this forum are made from. it is referred to as soda lime glass and melts more easily than hard (borosilicate) glass.
if you are planning to make beads you will most likely be using soft glass in 104 COE (for more about COE and compatibilty use the search box and you'll find lots of information)

soft glass brands include effetre, CIM, vetrofond, lauscha, reichenbach, double helix, bullseye and many more. bottle glass is usually soft glass too.
hard glass brands include pyrex, simax, momka, glass alchemy, and will be referred to generally as boro or borosilicate. its often used to make scientific glassware, as well as all the wonderful beads and sculptural work.
northstar and TAG make both hard and soft glass varieties.

one of the main differences between hard and soft glass is that hard glass is more resistant to thermal shock, which is why its good for scientific glassware, and also your pyrex cookware.

hope thats helpful and not too confusing!

[Shirley]

It also depends on how big the bead is that you want to make!

[Jeanne]

thanks for the quick replies.  )

Sorry I forgot to say that I'm got a propane/Butan torch and the glass rods that I'm working with are: Effetre / Vetrofond / Lauscha.

LOL

Jeanne