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Kiln repairs service and spares

Thermal Technologies is a supplier of Kilns and associate equipment and also provide Kiln repairs, Kiln Services and Kiln Spare Parts.

In the near future we will be adding a simple shopping cart for all our products especially spare parts.

Spares will be supplied Australia wide and Repairs & Service will be limited to NSW

Some of the spares we supply are Kiln Shelves, Kiln Furniture, Kiln Supplies, Kiln Electric parts, Kiln elements and much more.

Contact Peter on: 02 9602 1670 Peter Geddes or use the contact form.

Here is a list of the products supplied by Thermal Technologies.

Product Range

Kilns Hobby PMC Kilns Hobby Glass KilnsWarm Glass Studio Kilns Hot Glass Studio Kilns Ceramic Studio
Furnaces Laboratory Furnaces Dental Furnaces Alloy Casting Furnaces Microwave Autoclaves Tabletop

Glass slumping and fusing

To Get More Information on Vesta Kilns Contact Us

Glass Slumping Process

What is the glass slumping process? Glass slumping is bending or slumping glass into or over a mold. Generally glass is slumped into ceramic molds and bent over metal molds.

To achieve this, you must take your glass through a few heating and cooling phases. There are five steps to this glass slumping process.

Read each process to see how slumping is performed in glass fusing. If you have any questions, please contact me through the contact page.

Step One – Heating Up the Glass

You will be heating the glass up to a slumping temperature. This involves placing your glass on a prepared kiln mold inside your kiln.

After turning on your kiln, you will heat the glass to anywhere from 650 degrees Celsius to about 760 degrees Celsius, depending on the look you want to achieve and your individual kiln. Allow your glass to heat up slowly to avoid thermal shock. At around 540 degrees Celsius, your glass will begin to soften and appear glossy. Once you get past this stage you should not have any problem with thermal shock.

At around 700 degrees Celsius and 760 degrees Celsius, slumping occurs. Keep an eye on your glass and make notes of your progress.

Once your glass has slumped to your satisfaction, it is time to go to Step Two.

Step Two – Soaking the Glass

In this phase, you are going to want to allow your piece to soak. Longer soaking times cause the glass to flatten out and take on the shape of the mold. You will notice that the glass takes on a smoother appearance. Now on to Step Three.

Step Three – Cooling the glass

Once your glass has slumped into your mold and you are satisfied with the look, you need to cool your glass down. Some people cool off the glass rapidly by opening the lid and allowing the temperature to drop to about 600 degrees Celsius, while others just turn off the kiln and allow the piece to cool down on its own. This is a personal preference, take notes and determine what method suits your needs.


The reason for quick cooling your glass is to avoid devitrification. Devitrification can occur at temperatures above 1300 degrees Fahrenheit. Depending on how high a temperature you have reached with your glass, you can avoid devitrification by quickly cooling your glass.

Step Four – Annealing the Glass

Once your piece has cooled to about 540-565 degrees Celsius, you begin the annealing process. This will help relieve the stress that has built up in your glass. It is important to always anneal your pieces. Soak your piece at this temperature for about 20 minutes. Then slowly drop the temperature from the annealing point.


Another method of going through the annealing stage is by slowly cooling the glass. This method allows the glass to relieve the stress as it is slowly cooled off. This is especially helpful if you are not sure where the annealing point for your particular glass is located. Cooling slowly drops the temperature through different ranges of annealing. This method is referred to as constant linear annealing or shotgun annealing.

Stage Five – Cooling Glass to Room Temperature

Once you have taken your glass through the annealing stage, and relieved the stress, it is safe to cool your piece to room temperature. There are a couple of ways to accomplish this final glass slumping process.
You can turn off the kiln and allow it to naturally cool. If your particular kiln maintains heat, the natural cooling may be adequate. This is great for small pieces of glass.

It is still important for larger pieces of glass to continue to cool down slowly. This will again help with thermal shock. The best way to avoid this problem is to continually cool and soak your piece slowly.

By following these five steps of the basic glass slumping process, you should achieve your desired results. It is always a good ideal to keep detailed records in a glass fusing log of your procedures for future reference.

To See our hobby glass slumping and fusing kilns click here.

To Get More Information on Vesta Kilns Contact Us

Industrial and domestic Autoclaves

Weigao Biotech AutoclavesAutoclaves are a device to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C or more, typically for 15 to 20 minutes depending on the size of the load and the contents.

Autoclaves are widely used in microbiology, medicine, tattooing, body piercing, veterinary science, mycology, dentistry, chiropody and prosthetic fabrication.

Autoclaves are found in many medical settings and other places that need to ensure sterility of an object. Many procedures today use single-use items rather than sterilized, reusable items.

This first happened with hypodermic needles, but today many surgical instruments (such as forceps, needle holders, and scalpel handles) are commonly single-use items rather than reusable.

Air removal in Autoclaves

It is very important to ensure that all of the trapped air is removed, as hot air is very poor at achieving sterility. Steam at 134 °C can achieve in 3 minutes the same sterility that hot air at 160 °C takes two hours to achieve.[6] Methods of achieving air removal include:

Downward displacement (or gravity type) – As steam enters the chamber, it fills the upper areas as it is less dense than air. This compresses the air to the bottom, forcing it out through a drain. Often a temperature sensing device is placed in the drain. Only when air evacuation is complete should the discharge stop. Flow is usually controlled through the use of a steam trap or a solenoid valve, but bleed holes are sometimes used, often in conjunction with a solenoid valve. As the steam and air mix it is also possible to force out the mixture from locations in the chamber other than the bottom.

Steam pulsing – Air dilution by using a series of steam pulses, in which the autoclaves chamber is alternately pressurized and then depressurized to near atmospheric pressure.

Vacuum pumps – Vacuum pumps to suck air or air/steam mixtures from the chamber.

Superatmospheric – This type of cycle uses a vacuum pump. It starts with a vacuum followed by a steam pulse and then a vacuum followed by a steam pulse. The number of pulses depends on the particular autoclave and cycle chosen.

Subatmospheric – Similar to superatmospheric cycles, but chamber pressure never exceeds atmospheric until they pressurize up to the sterilizing temperature.

Because autoclaves uses saturated steam under high pressure to achieve sterilizing temperatures, proper use is important to ensure operator safety.

Prevent injuries when using the autoclaves by observing the following rules:

  • Wear heat resistant gloves, eye protection, closed toed shoes and a lab coat, especially when unloading the autoclave.
     
  • Prevent steam burns and shattered glassware by making sure that the pressure in the autoclave chamber is near zero before opening the door at the end of a cycle. Slowly crack open the autoclave door and allow the steam to escape gradually.
     
  • Allow items to cool for 10 minutes before removing them from the autoclave.
     
  • Never put sealed containers in an autoclave. They can explode. Large bottles with narrow necks may also explode if filled too full of liquid.
     
  • Never put solvents, volatile or corrosive chemicals (such as phenol, chloroform, bleach, etc.), or radioactive materials in an autoclave.

Inspect your autoclave components regularly. If you find a problem, notify your area mechanic. Do not operate an autoclave until it has been properly repaired.

To Get More Information on Purchasing Your Autoclave Contact Us

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Different types of glass beads

Millefiori glass beads

The Venetian Millefiori glass beads are famous around the world.

Translated to mean "a thousand flowers", Millefiori glass beads are made by grouping many long pieces of glass together, heating them, then slicing small pieces from the resulting roll.

Many of these pieces are then melted onto the surface of a single glass bead. This makes the final result look as though the bead is filled with flowers.

They can also use other geometric designs, but are most famous for their floral patterns.

Lampwork glass beads

Glass beads that are made with the lampwork technique are made by hand. It takes a lot of skill to create these round, globe-like glass beads, and they can be fairly intricate.

Many European lampwork beads that are produced today have been passed down through each generation within a family. Their techniques produce highly artistic and beautiful designs.

They can have flower patterns, swirls, dots inside the bead or on the surface, and in themselves are amazing and artistic.

Pressed glass beads

Molds are used to create glass beads with this technique, particularly when a specific shape is needed.

Exterior detail is pressed into the bead, creating patterns, shapes and lines.

Blown glass beads

Glassblowing dates back to ancient empires, and blown glass beads today use the same technique.

Also known as furnace glass beads, these achieve quite attractive results.

A tube is used to shape the molten glass bead with air while it is in a liquid state. The resulting glass bead is hollow.

Crystal glass beads

Crystal glass beads contain lead, and refract light at a rate that approaches that of a diamond.

The lead content makes the bead stronger, allowing precise facets to be cut into the crystal glass bead.

Firepolished glass Beads

Often mistaken for crystal glass beads, firepolished beads have facets, but they do not have the lead content. The facets are cut and then melted until smooth to create an extremely distinct shape.

They can have metal in the middle to produce a glittering effect. The facets of these glass beads are emphasized by the metallic center, making this partnership of firepolish and metal extremely attractive.

Make sure your beads are annealed

Glass shrinks when it cools. The beads are pulled out from the flame to cool; they are left out in the open air which means that while the outside of the bead is rapidly cooling, its inside is still very hot. The uneven temperature resulting from this method will often cause a bead to crack.

Kiln annealing is a process by which both the inside and outside temperature can be closely regulated. The bead is placed in high temperature to make sure that all the glass is evenly heated. After several hours, the bead can now be put out at room temperature for cooling. But it is important to make sure that the glass beads you make or buy are all kiln annealed.

A kiln for annealing beads can be seen here

PS: Google books has some interesting books on Glass Beading and this one especially is a quick reference and some great photos of what can be achieved. Click here to read ( opens in a new window)

Synotherm microwave dental furnaces

Microwave heating is emerging                      as the innovative, time saving  and energy efficient technology  for today’s demanding dental  sintering processes.

 

Microwave heating is emerging as the innovative, time saving and energy efficient technology for today’s demanding dental sintering processes.

For example, alumina the most common ceramic which until recently, required conventional heating to 1600C and 2 hours of hold time to achieve 98% of theoretical density, can now be sintered much faster, at lower temperature (1400C) and with no hold time, using microwave energy to achieve the same degree of densification , but with substantially less grain growth.

The microwave process provides similarly spectacular results when firing zirconia with rapid heating times of 40-45 minutes to 1500C compared to typical conventional radiant furnace process heating times of around 7-9 hours.

Microwave heating is emerging                      as the innovative, time saving  and energy efficient technology  for today’s demanding dental  sintering processes.
Why is microwave heating      so efficient and so fast? Why is microwave heating so efficient and so fast?

In the case of the microwave process, absorption followsvolumetric with the conversion  of electromagnetic energy intothermal energy.

The heat is generated internally within the material instead of from external sources.This is an inverse heating profile – inside out, unlike conventional heating which is outside in.

In this way, the heating is instantaneous, rapid, very efficient and with energy savings approaching 90%.

How microwave heating provides stronger materials with finer grain.

Above all, the most outstanding features observed from microwave sintered materials are their finer grain structures and increased strength.

Conventional slower heating systems expose the material which is being processed to longer periods within the critical temperature range where most grain growth occurs.

By comparison, microwave heating times are generally 10 times faster – producing sintered materials which approach 99.8% theoretical density. 

How microwave heating provides  stronger materials with finer grain.

To read more about Synotherm Microwaves visit our products page Click Here.

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