How to melt glass in a muffle furnace - technology, melting point, features

How to make glass?

Glass is produced by cooling molten components at temperatures between +300 and +2500 °C, at a rate sufficient to prevent the formation of visible crystals. Sand alone is enough to make glass, but the temperature required to melt it will be much higher.

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Is it possible to melt glass and what is needed for this?

Glass melting is carried out at high temperatures. There is no exact value; it is determined experimentally. The heating time depends on what impurities and in what quantity are contained in the glass. Usually, for each specific type, the average values ​​of the melting temperature of glass are determined, which were obtained by studying and testing them in laboratories. The most common types melt at the following temperatures:

• Plain glass – 700-750 oC.
• Glass for making dishes and containers – 1200-1400oC.
• Ampoule – 1500-1800oC.
• Quartz – 1650°C.

At enterprises that work with glass, the temperature in the furnaces is maintained at 1600°C.

Bottle glass

There are two methods of melting glass - casting and bending. When casting, it melts to a liquid state and the necessary forms (molds) are filled with it. Bending is a process in which glass is heated to a viscous state and becomes bendable and pliable. In this state, glassblowers work with it, bending and stretching the material.

Glass bending

As you can see, the temperature of molten glass has high values, which can be achieved if you use a high-quality muffle furnace.

Furnaces for melting glass and their types

A muffle furnace is a device for uniform heating of substances. It consists of:

• Cases.
• A chamber, also called a muffle.
• Doors.
• Control unit.

The body can be made of stainless steel or carbon. Stainless steel models last much longer.

The muffle is the most important part of the furnace, because it is in it that the glass is melted and the heating elements are located. It can be made of ceramics, corundum or special fiber.

Another important part is the control unit, which is responsible for selecting the mode and setting the oven. Now all furnaces are equipped with electronic units, which have replaced dial units.

Muffle furnace diagram

Whether glass can be melted in a particular muffle furnace depends on the type of device itself. There are different types of them, which differ:

• Maximum heating temperature.
• Heating method.
• Device.

Muffle furnace SNOL

The most important characteristic is the temperature range. According to this parameter, furnaces are divided into:

• Low temperature – up to 400°C.
• Medium temperature – up to 900oC.
• With high temperatures – up to 1400°C.
• High temperature – up to 2000oC.

Furnaces also differ in their processing mode, they are:

• Operating in air (conventional).
• Vacuum (heating is carried out in a vacuum).
• Operating in a gas environment (heating is carried out in the presence of various gases, for example, hydrogen, nitrogen, argon, etc.).

There are models that are intended for home use, and there are professional units that are used in laboratories or large enterprises. Both domestic and foreign manufacturers produce various versions of muffle furnaces. The Lithuanian company SNOL has proven itself well.

Preparation of material

Before melting glass at home, you should prepare for the procedure. Collect unwanted old cans and bottles. Before melting, these containers must be cleaned and dried. Remove labels from bottles.

You should also get rid of any glue that remains on the glass. By soaking the bottles, you can easily scrape off any remaining glue. Use a small spatula, scrap plastic card, or wallpaper scraper for this purpose.

If the inscriptions are painted directly on the glass itself, it can be left. But it is necessary to take into account that after such melting, a small amount of paint will remain on the glass.

Do-it-yourself glass bending furnace - Metalworker's Guide

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Good afternoon, forum users! Awesome forum! I learned more information about glass making than anywhere else. I especially liked the articles on sandblasting. So, in continuation of the topic, as it were. The point is that I want to do sandblasting with fusing elements.

I started studying the prices of furnaces for this very fusing and, to be honest, I was very amazed. They charge amazing prices for a tiny stove. It's not worth it though. And so the idea arose to assemble this technical miracle myself. If anyone is interested, I will post all my work, drawings, calculations, addresses.

Maybe someone can tell me something interesting.

I agree, the topic is very interesting and useful, I myself have deeply studied this glass processing technique and practice it. You can’t imagine what masterpieces can be made using the fusing technique, it’s not just diamonds and squares glued to the mirror, there really are paintings that are simply mesmerizing. But these are lyrics.

I work on an M-800 stove. Few people want to share the secrets of this technique, especially the glass fusion modes. I decided to make a table on sintering modes for different glasses, so that it would be clear to beginners too.

I myself work with American glass Spectrum S96, for this glass I enter data into the table and will definitely post it! Spectrum is one of the most expensive glasses, I want to try Bryansk glass, although it is criticized, and Chinese glass, they are of worse quality but cheaper.

I don’t know the modes for these glasses, but I will fuse and lay out the modes experimentally. If anyone knows what modes can tell me. Let's try it together and post it!

I also started trying with ordinary window glass, well, there’s a song here

ANMitin. It’s great that I unexpectedly met you like this - I was all going to find a like-minded person on the forum and together look for optimal modes for sintering. I recently started fusing myself too. I also use the M-800 oven.

For now I’m working on Spectrum glass - and I think this is quite enough for me, for starters). Bryansk glass can be easily sintered if the dimensions are small - the same squares and diamonds - it’s better not to even bother with something big. It will bake normally, but after six months it will suddenly crack.

I had a piece of paper with the regime somewhere on Baoli glass, they gave it to me at the company where I bought the stove, if I find it, I’ll definitely post it. At the moment, I have sintered small products with a maximum size of 15x15 cm and 14x25 cm, double-layer glass, and a small detail - squares.

sintering effect - medium and complete. Tomorrow night I will post samples for clarity. I will be glad to mutual cooperation.

I haven't bought anything yet. Until I figure everything out, I won’t make any purchases. But I can tell you about the prices. In general, cotton wool costs a hundred and a little rubles per kilo.

Slabs 1000x500x75 brand KTP cost a little less than 2 thousand rubles per joke, you can look for other slabs ShVP-350, for example, but their thickness is already 10 cm. 1000x500 are the largest standard ones that I found on the net. Other sizes are already available to order. And it will cost a pretty penny.

So I relied on this size. In the end, I roughly calculated that a stove of my size would cost about 20-25 thousand rubles, and you must agree that you can’t buy a stove of that size for that kind of money.

If we talk about your dimensions of 2x1.5 m, then I don’t even know, it should be calculated at 380 volts three-phase voltage. My spirals will be located in the upper part of the working area of ​​the oven. I'll post the drawings at the completion stage soon.

Fusing - DIY stained glass art

Fusing as a technology for working with glass appeared only at the end of the twentieth century, but has already managed to interest craftsmen around the world. Thanks to special processing of materials, amazing multi-colored decorations, stained glass windows and tableware are obtained. Try and master the magical fusing technique.

Fusing: classification of types

Fusing is a special type of stained glass processing. After laying out the mosaic glass picture, the multi-colored shards are sintered together in a kiln, forming a stained glass window without wood, iron or any other joints.

The fusing technology is the same in all cases - glass fragments, granules, crumbs are laid out in a certain form in the form of an intended pattern, then sent to an oven heated to 800-1200 degrees. The finished products are left in the oven for a while and then taken out.

But the styles of processing the finished product using the fusing technique differ. To give the workpiece a specific shape, glassblowers use fusing shaping techniques.

Bending

This technique gives the workpiece a certain shape. To do this, the product is heated again, as in the first stage of fusing, and shaped in accordance with the idea. This technique is used to work with utensils - vases, dishes and plates.

Fire polishing

Polishing is aimed at imparting additional smoothness to the surface of the product using a glass furnace. This technique helps to get rid of uneven surfaces of both large stained glass windows like a glass door insert and small items like beads.

Combined carding

The technique is based on giving a specific shape to a workpiece using specialized tools. This style helps to remove all defects along the edges of small items: brooches, beads and pendants.

Fusing is to a certain extent similar to the lampwork technique - melting multi-colored glass to give it a certain shape. But lampwork works with small sizes - glass beads, brooches, and using the fusing technique you can create large products, even a stained glass door.

Required materials and tools

Fusing works with different colors of glass depending on what composition you plan to fuse. In this case, you need to ensure that all glass parts have the same coefficient of thermal expansion - an indicator of strength, otherwise, when fused, the product will become very brittle and fragile.

For a full-fledged creative process, you will need glass shards, granules and crumbs, as well as liquid glass or silicate glue.

Before work you need to stock up on certain tools:

• Sintering molds made of porous materials;

• Special processing solutions and mixtures;

• Separator - a separator between the workpiece and the mold so that the product does not stick;

All these devices can be purchased at specialized craft stores. Of course, you can make baking dishes and a separator yourself (for example, from plaster), but only if you already have some experience in fusing techniques.

You will also need a specialized muffle furnace for the job. But those who do not have one can safely use a microwave.

Fusing: master class

To consolidate your knowledge of fusing in practice, try making a small simple stained glass product with your own hands - a butterfly. To do this, stock up on white base glass and multi-colored pieces of glass.

• Draw a sketch of the image on paper, marking the areas of the drawing with the necessary colors.

• Take the glass base and use a glass cutter to give it the shape of the blanks.

• Clean the finished parts and coat them with a specialized compound. Measure and prepare colored blank parts in the same way.

• Create blanks, starting from large parts and moving on to smaller ones.

• Place in a special porous form and microwave for a few minutes. Then leave the mold to cool in the microwave for 30-40 minutes without opening it.

After mastering simple fusing techniques, try baking something more significant. For example, please your loved ones with new Christmas tree decorations.

Get creative with colors and shapes of your products. Combine round, rectangular and square pieces, layer colors on top of each other to end up with a unique piece.

Advice from the experts

If you are just learning fusing, listen to the advice of professionals. They will help you do your work better and reveal little tricks to this craft.

• If you want the product to have a hanging loop, place it between the pellets before sintering in the kiln. Thanks to the ceramic or plaster hood, at high temperatures nothing will happen to either the product or the microwave oven.

• If you need through holes in the product, insert thermal paper rolled into a thin tube between the blanks. This must also be done before the actual sintering process.

• Many people are attracted to products with many air bubbles inside. To achieve this effect, sprinkle a pinch of salt between two pieces.

It is necessary to say about the harm of temperature differences for the product. If you open the microwave immediately after the process is completed, the operation will be damaged. Due to sudden temperature changes, fresh glass becomes brittle.

Features of melting glass melt at home

You can melt glass at home, but, as in any craft, you need special equipment and compliance with safety precautions. To melt glass, you must strictly maintain the temperature regime and time intervals, since if the time delay is not observed or the temperature increases even by a few degrees, the result can be completely different.

You can use a gas torch to solder the elements. To fully work with glass, you need to purchase a special furnace with a temperature regime of up to 1000 0 C. Glass bottles, perfume bottles, and other glass products commonly used in everyday life are suitable for creating new products. For a high-quality result, it is necessary to thoroughly clean the material from labels and other foreign elements. Melting glass with paint is allowed, but it should be taken into account that this paint will affect the final result.

At home, the fusing technique is most often used. This look does not require a clear outline, but rather helps create a watercolor result. The technique is suitable for making jewelry and other small creative items.

Melting glass at home is associated with a number of difficulties, including calculating the melting temperature of different materials and accurately maintaining a given mode and time.

Sources:

• https://labor-snol.ru/news/kak-rasplavit-steklo
• https://promplace.ru/steklo-staty/-1990.htm
• https://oknaforlife.ru/poleznaya-informatsiya/temperatura-plavleniya-okonnogo-stekla
• https://www.syl.ru/article/319546/temperatura-plavleniya-stekla-maksimalnyie-i-minimalnyie-pokazateli

Fusing furnace: device, principle of operation, DIY production

Modern life cannot be imagined without installations for heat treatment of glass objects.
With their help, stained glass windows and multi-colored glass products are created (fusing furnace), curved surfaces (glass bending furnace), and glass is tempered to improve its strength characteristics.

Such thermal installations have found their application both in small industries and private workshops, and in mass production.

What is fusing?

Fusing is the process of fusing into each other and then sintering two or more glasses of different colors without the use of metal components. There are no seams left on such products. A glass baking oven is a thermal heating device powered by electricity (gas and even wood-burning stoves are less commonly used).

In its working chamber the process of heating and subsequent melting with sintering of the resulting composite material takes place. The first fusing installations for creating stained glass were used in the 1990s in Germany.

Device

An electric heating installation for fusing consists of basic assembly units, such as:

1. Furnace body.
2. Brick lining.
3. Working chamber.
4. Door or lid with seal.
5. Thermoelectric heating element.
6. Control unit for operating modes and temperature.
7. Grounding conductor.

Industrial large glass tempering plants are complex conveyor-type units. They consist of roller units for feeding and unloading the processed material, a heating chamber and a rapid air cooling system.

Glass bending furnaces have a special curved profile surface in the working chamber. This is necessary to obtain glass sheets of the required geometry.

Principle of operation

The fusing and bending processes occur when the glass reaches a temperature of 600 - 800 degrees Celsius. Hardening occurs at a temperature of 650 - 680 degrees, followed by rapid cooling of the material. The temperature inside the oven is controlled using a remote electronic unit and controls.

To achieve these temperatures, the glass melting furnace is heated using electrical resistance elements. They are built into the space of the stove's working chamber, or into its lid.

In fusing furnaces, the process of fusing multi-colored pieces of glass into each other occurs. In bending ovens, glass softens and takes the shape of the base template on which it is located.

With both processing methods, glass is also tempered, which can be carried out separately from these processes. At the end of processing, the workpieces are cooled with air.

Types of furnaces

All furnaces for glass processing can be divided into 2 groups:

• industrial dimensional installations,
• small electric stoves for private use.

Large industrial devices are equipped with rollers for feeding large sheets of glass into them. With their help, large decorative elements, furniture, shop windows, lampshades, window glass, etc. are created.

Small glass melting furnaces have small working chamber dimensions. With their help, various crafts, jewelry, dishes and other small items are made.

How to choose?

You should choose a furnace for melting glass for your production needs based on the type of fuel it will be operated on, the expected power and the amount of product produced. Electric ovens are most often used.

In order to accurately observe technological conditions, it is necessary to carefully read the technical documentation for the product, what temperature and time the oven can produce, how quickly or slowly this or that stage of processing of raw materials or product occurs.

Financial capabilities should also be taken into account, as well as the projected payback period for new equipment. Below we will look at popular manufacturers and models.

Manufacturers and models

• Mini-furnace for fusing “Studio Pro”. Russian production. The dimensions of its working chamber are 203 x 203 x 114 mm. The stove has the ability to load vertically and sideways, which is especially important for processing small parts. Power is supplied from a 220 volt network, the oven power is 2.2 kW, the maximum operating temperature is 980 degrees Celsius. Its cost is 70,000 rubles.
• Fusing furnace "FMGroup PF-1106". Russian production. Its dimensions are 1000x1500x1600 mm, the maximum thickness of glass for processing in it is 20 mm, the dimensions of the loaded glass sheet are no more than 1100 by 600 mm. Power is supplied from a 380 volt network, the oven power is 9 kW. The price of such a device is 140,000 rubles.
• Muffle furnace for fusing and bending processes at ZapSibOgneupor LLC. The dimensions of the heating chamber are 600x600x230 mm, power - 4 kW, operates on a 220 volt network. The heating element elements are located in the top cover, the maximum operating temperature is 950 degrees Celsius. The price for fusing furnaces of this model is 80,000 rubles.
• Installation of gravity bending of glass “FMGroup PGM 1511”. Russian production. It is a two-chamber unit, on top of which a heating module moves. The stove is equipped with a microprocessor temperature controller. The power of the installation is 24 kW, the space of the working chambers is 2100x1100x450 mm, it is powered by a 380 volt power supply, the maximum temperature in the chamber is 1000 degrees Celsius. Its cost is 520,000 rubles.
• Fusing furnace for firing ceramics PK515K. Russian production. It is a “suitcase” type stove, the heating electric element is located in the top cover. It has a programming system for fusing modes. The dimensions of the working chamber are 1300x750x100 mm, power 6 kW, powered by 380 volts, maximum heating temperature 1150 degrees Celsius. Its cost is 205,000 rubles.
• Glass bending oven KFM 1.5. Russian production. The dimensions of the working chamber of this installation are 1500x600x500 mm. Its power is 7 kW, operating voltage is 380 volts, maximum operating temperature is 850 degrees Celsius. The cost of such a stove is 170,000 rubles.
• Mini glass tempering oven Gangxin GX-P0609. These units are manufactured in China. Industrial installation for medium and large production. Powered by 220, 380 and 415 volt networks. The power of such a device is 70 kW, its overall dimensions are 6600x2200x1300 mm, the thickness of the processed glass is from 3 to 19 mm. The price of such an installation is from 42,000 to 55,000 US dollars.

DIY fusing oven

It’s quite easy to make a simple fusing oven with your own hands. Below is the procedure for assembling such a stove with a top loading and an electric heating element in the lid (a “suitcase” type fusing stove).

Materials and tools

To make such a device you will need:

• Metal profile for frame and legs.
• Magnesium glass sheet.
• Galvanized sheet steel.
• Mirror stainless steel.
• Heat-resistant sealant.
• Mineral wool for thermal insulation of the furnace body.
• Fireclay brick, dry mixture for its laying.
• Silicone seal for the installation base.
• Thermal heating element, temperature sensor.
• Fasteners (screws or bolts).
• Grinder (angle grinder).
• Drill or screwdriver.
• Trowel, mallet.
• Bucket for preparing the solution.
• Welding machine.
• Marking and measuring tools (ruler, tape measure, core, building level).

Step-by-step manufacturing instructions

A homemade fusing furnace is manufactured in several stages, which will be listed below:

1. The frame of the future installation is made from a profile corner or pipe. A welding machine is used for this. The top cover and the base of the furnace are welded, to which the support legs are welded.
2. The outer perimeter of the frame is sheathed with galvanized steel, and the inside with glass-magnesium sheet.
3. All sheet matings are processed using heat-resistant sealant.
4. The internal space between the sheets is filled with mineral wool to thermally insulate the working chamber.
5. Layers of refractory fireclay bricks are laid along the perimeter of the top cover and base.
   Excess mortar is removed and the masonry is dried naturally for 3 to 4 days.
6. The glass-magnesium sheet is covered with mirror stainless steel.
7. A sealant made of heat-resistant silicone is glued along the perimeter of the base of the future fusing furnace.
   The hinges and handle are screwed to the top cover of the “suitcase” using self-tapping screws. If available, it is recommended to use gas shock absorbers instead of conventional hinges. This will facilitate the process of lifting the lid, the total weight of which is more than 20 kilograms.
8. An electric heating element (nichrome spiral) is installed inside the furnace lid body and a temperature sensor on the outer panel of the unit.
9. The door hinges are screwed to the body of the installation base using self-tapping screws.
10. A trial run and testing of heating electrical equipment is carried out.

Here is a photo of finished homemade structures:

Photo 1

Photo 2

Addition

In addition to the method given above, small pieces for the production of jewelry or buttons can be processed in a microwave oven specially prepared for this purpose. It is important that in such a device further cooking is excluded.

There are small round crucibles such as the Hot Pot (Microwave Kiln). Their diameters are only 80 and 120 millimeters.

Hot Pot (Microwave Kiln)

As a basis for such crafts, a special paper substrate is used, which is placed on the bottom of the crucible.

Features of operation

When working with an electric fusing furnace, you must follow basic safety rules:

• The device housing must be grounded or neutralized. Before starting work, make sure that the grounding wire is securely connected to the electric stove.
• During the process of sintering or molding of glass blanks, it is prohibited to touch the operating installation with your hands.
• It should be remembered that such thermal electrical equipment should be installed no closer than 10 centimeters from the wall.
• It is necessary to remove the finished product from the fusing oven after the material and the working chamber of the oven have completely cooled, in order to avoid burns. It is recommended to use protective gloves and special forceps.
• When cleaning, the oven must be cooled to room temperature and disconnected from the power supply.
• Thermoelectric heaters are subject to periodic cleaning and replacement of failed electric heating elements.

Conclusion

Fusing furnaces are widely used not only in large industrial enterprises, but also in private workshops. The range of glass products produced in them is incredibly wide - from buttons to shop windows and stained glass for public buildings and structures.

Based on financial capabilities, such a device can be easily purchased for home use, or you can make it yourself. You can also use an old working microwave. Loading…

Principles for calculating melting point

Calculating the melting temperature of glass at home is a very difficult task. It will be associated with many difficulties, among which it is worth highlighting:

1. The need to ensure a gradual increase in the temperature of the molten body by strictly one degree. Otherwise, it will be impossible to reliably establish at what indicator the process of transition from solid to liquid begins, that is, the experiment will end in failure.
2. You need to find a very accurate thermometer that can measure temperatures up to 2 thousand degrees Celsius with a minimum error. The best option is an electronic device, which will be too expensive for home experiments.
3. Conducting an experiment at home, in principle, is not the best idea , because you will have to look for a container in which you can melt glass, get a stable source of fire that can provide the required level of heating, and buy expensive equipment.

Basic values

Approximate values ​​for the transition of glass into a liquid state for some types:

- melting point of bottle glass - 1200-1400 degrees Celsius; — the melting point of quartz glass is about 1665 degrees Celsius; - melting temperature of ampoule glass - 1550-1800 degrees Celsius; - liquid glass melting point - 1088 degrees Celsius.

For the last substance, you can indicate an exact figure, because it does not exhibit amorphous properties, since it is an aqueous alkaline solution of sodium and potassium silicates. It is also worth considering that glass does not melt immediately, but first turns into a viscous caramel-like state. This property is used by glassblowers to create various products and souvenirs.

You can do this craft at home. There will be no shortage of raw materials, since you can find a lot of glass bottles right on the street. And an ordinary gas lamp is also suitable as a device for softening the material. You can then sell your handmade products as souvenirs and earn good money.