Smaltatura ceramica ad immersione, come smaltare la terracotta e la ceramica

Fare CERAMICA

7 May 202218:57

Summary

TLDRThis video is a comprehensive guide on dip glazing ceramics. The instructor meticulously explains the process, from preparing the glaze solution to immersing and cleaning the pieces. He highlights the benefits of dip glazing, such as minimal waste and ease of execution without specialized equipment. The video delves into the importance of adjusting glaze density based on the porosity of different clay bodies, ensuring uniform absorption. The instructor also demonstrates techniques for handling pieces during immersion, using tongs and hand-dipping methods. Additionally, he provides insights on ensuring proper coverage and cleaning excess glaze, making this video an invaluable resource for both novice and experienced ceramic artists.

Takeaways

🧯 Immersion glazing is a practical technique as it produces minimal glaze wastage and pollution compared to other glazing methods.
🏡 Immersion glazing can be done at home without specialized equipment like spray booths or respirators. Only a bucket, water, and powdered glaze are needed.
⚖️ The density of the glaze mixture is important and should be adjusted based on the porosity and material of the ceramic pieces being glazed.
🥣 For pieces with different porosities, separate glaze containers with different densities may be needed, or immersion times can be varied.
🦷 Pieces with thinner sections will saturate and absorb less glaze compared to thicker sections.
🥽 Proper cleaning of bisque pieces before glazing is crucial to ensure good glaze absorption and avoid defects.
🤏 Tongs or grips are essential tools for safely handling and immersing pieces in the glaze.
🛀 When immersing, the last part to enter the glaze should be the first to exit to ensure even glaze absorption.
💧 After immersion, excess glaze should be allowed to drip off and any remaining drips or uneven spots should be smoothed out.
♻️ Excess glaze can be recovered, strained, and reused to minimize waste.

Q & A

What is the main topic of this video?
-The main topic of this video is dip glazing, which is a type of glazing technique used in ceramics. The video provides a detailed explanation of the dip glazing process, including the preparation of the glaze mixture, tools needed, and step-by-step instructions for dipping various ceramic pieces.
What are the advantages of dip glazing mentioned in the video?
-Two main advantages of dip glazing are mentioned: 1) It is a practical technique with minimal glaze wastage, reducing environmental pollution and costs. 2) It can be done at home without specialized equipment like spray guns or booths.
How is the glaze mixture prepared for dip glazing?
-The glaze powder is mixed with water in a bucket the night before, as per the supplier's instructions. The next morning, it is thoroughly stirred with a wooden tool and then sieved through a fine mesh into another container to remove any lumps or crystals that might cause defects.
What is the importance of measuring the glaze density?
-Measuring the glaze density with a densimeter is crucial because different ceramics have varying levels of porosity. The ideal density for most ceramic glazes is around 45, while for cristalline glazes, it is around 40. The density needs to be adjusted based on the porosity of the pieces being glazed.
How does the porosity of the ceramic pieces affect the glazing process?
-The porosity of the ceramic pieces affects how much glaze they absorb. More porous pieces, like terra cotta, will absorb more glaze and require a longer dipping time or a denser glaze mixture. Less porous pieces, like stoneware, will absorb less glaze and may require a thinner glaze mixture or shorter dipping time.
What tools are used for dipping the ceramic pieces in the glaze?
-Various types of tongs or pliers are used for dipping ceramic pieces in the glaze. The video demonstrates the use of a common type of tongs, as well as a custom-made plier tool made by the narrator's father, which allows for adjusting the grip.
Why is it important to clean the ceramic pieces before glazing?
-It is crucial to clean the ceramic pieces before glazing to remove any dust, cobwebs, or residue that might interfere with the glaze's absorption into the pores of the piece. The video suggests using compressed air, damp sponges, or even re-firing the pieces if they are excessively dirty.
What is the proper technique for dipping ceramic pieces in the glaze?
-The proper technique involves immersing the piece into the glaze from one side and lifting it out from the opposite side. This ensures that the last part to enter the glaze is the first part to exit, minimizing uneven glaze absorption. For pieces with narrow openings, the glaze can be poured into the piece before dipping.
How should the excess glaze be handled after dipping?
-After dipping, the excess glaze should be allowed to drip off, and any remaining drips can be gently spread out with a finger or a tool like a rib. The bottom of the piece should be cleaned with a paper towel or damp sponge to remove any excess glaze.
What is the final step mentioned in the video after dip glazing?
-The final step mentioned in the video is firing the glazed ceramic pieces in a kiln. The narrator mentions checking the results once the pieces come out of the kiln the next day or the day after.

Outlines

00:00

🏺 Introduction to Immersion Glazing

This paragraph introduces the topic of immersion glazing, explaining why it is a practical and environmentally-friendly method. It describes the necessary materials and the process of preparing the glaze solution by mixing the glaze powder with water and straining it to remove any lumps or crystals. The paragraph also mentions the use of a densimeter to measure the density of the glaze, which should typically be around 45 for ceramic glazes and 40 for crystalline glazes.

05:03

🔍 Porosity and Its Impact on Glazing

This paragraph discusses the importance of porosity when glazing ceramics. It explains how different clay bodies, such as terra cotta, stoneware, and earthenware, have varying levels of porosity, which affects how the glaze is absorbed. The paragraph suggests adjusting the glaze density or immersion time to account for different porosities. It also highlights the need to keep separate glaze batches for terra cotta and stoneware if working with both clay types.

10:05

🛠️ Immersion Glazing Process

This paragraph provides a detailed walkthrough of the immersion glazing process. It covers the use of tongs or pliers to hold the ceramic pieces, the importance of considering the shape and opening of the piece when immersing, and the technique for ensuring even glaze coverage. The paragraph also demonstrates the immersion process for different types of objects, such as a box and a terra cotta piece, and explains how to touch up areas that did not receive enough glaze.

15:07

🧽 Cleaning and Finishing Steps

The final paragraph focuses on the cleaning and finishing steps after immersion glazing. It emphasizes the importance of cleaning the bisque ware before glazing and suggests using compressed air or a damp sponge to remove any dust or debris. The paragraph then demonstrates how to clean the excess glaze from the bottom of the glazed piece using a sponge or paper towel, and how to recover and reuse the excess glaze by straining it. It also covers techniques for removing any glaze drips or blemishes before firing.

Mindmap

Keywords

💡Immersion Glazing

Immersion glazing is a method of applying glaze to ceramic pieces by dipping them into a liquid glaze mixture. This technique is described as practical and efficient, as it minimizes glaze waste and does not require special equipment like spray guns or exhaust systems. The video emphasizes its simplicity, as it only requires a bucket of water and powdered glaze.

💡Glaze Density

Glaze density refers to the thickness or viscosity of the liquid glaze mixture. The video explains that the density is typically measured using a hydrometer and is adjusted depending on the porosity of the ceramic pieces being glazed. For most ceramic pieces, a density around 45 is recommended, while for crystalline glazes, a lower density of around 40 is used due to its lighter consistency.

💡Porosity

Porosity refers to the degree of tiny pores or holes present in the fired ceramic piece (known as the 'biscuit'). The video emphasizes that porosity can vary depending on the clay body and firing process used. More porous pieces, like those made from red terracotta clay, will absorb the glaze faster and may require a longer dipping time or a denser glaze mixture to achieve an even coating.

💡Biscuit Ware

Biscuit ware refers to the ceramic pieces that have been fired once (bisque-fired) before the glazing process. The video stresses the importance of properly cleaning and preparing the biscuit ware before glazing, as any residual dust or debris can affect the glaze absorption and create defects.

💡Glaze Application

The video provides detailed instructions on the proper technique for applying the glaze by immersion. It emphasizes the importance of dipping the piece evenly and consistently, as well as allowing excess glaze to drip off and touching up any missed areas with a brush. The application method may vary slightly depending on the shape and size of the piece being glazed.

💡Tongs/Pincers

Tongs or pincers are essential tools for handling and dipping ceramic pieces during the immersion glazing process. The video showcases different types of tongs, including adjustable pliers modified for better grip, and emphasizes the importance of using a firm and secure grip to prevent the piece from slipping during immersion.

💡Glazing Container

The glazing container, often a bucket or larger vessel, holds the liquid glaze mixture for immersion. The video highlights the importance of using a container that is appropriately sized for the ceramic pieces being glazed, allowing for easy maneuvering and complete immersion.

💡Glaze Sieving

Sieving or straining the liquid glaze mixture is a crucial step mentioned in the video. It involves passing the mixture through a fine mesh sieve to remove any lumps or undissolved particles, ensuring a smooth and consistent glaze application without defects.

💡Glaze Consistency

Glaze consistency refers to the uniform texture and thickness of the glaze coating achieved through proper application and adjustment of the glaze mixture. The video emphasizes the importance of maintaining a consistent glaze consistency across different ceramic pieces, as variations can lead to uneven coverage or defects.

💡Glaze Firing

Although not explicitly covered in the video, the final step after glazing is firing the pieces in a kiln at high temperatures to melt and fuse the glaze onto the ceramic surface. The video briefly mentions the expectation of observing the glazed pieces after firing to evaluate the quality of the glaze application.

Highlights

Immersion glazing is a practical and eco-friendly method as there is almost no waste or pollution, and it can be done at home without specialized equipment like spray booths or compressors.

The glaze powder needs to be mixed with water the night before, and then sieved the next morning to remove any lumps or crystals that could cause defects.

A densimeter is used to measure the density of the glaze slip, which typically ranges from 40 to 45 for ceramic glazes, depending on the porosity of the pieces.

More porous pieces like terracotta absorb the glaze more readily, so the pieces may need to be immersed for a longer time or the slip density adjusted accordingly.

Thinner sections of a piece will saturate with glaze more quickly, so care must be taken to ensure even absorption throughout the piece.

Different types of tongs or pinsers are used to grip and immerse the pieces, with larger tongs for bigger items like umbra stands.

The container size must be appropriate for the size of the pieces being dipped, with larger containers for bigger items like plates.

Proper cleaning of the pieces before glazing is crucial, using compressed air, damp sponges, or even re-firing old bisque ware to remove any dust or debris that could clog the pores.

When dipping, the last part of the piece to enter the glaze will be the first part to exit, so a consistent dipping motion is important for even glaze application.

For pieces with narrow openings like vases, the glaze can be poured in first before immersing the entire piece.

Wooden tools are preferred for mixing the glaze slip to avoid contamination from metal shavings.

Frequent remixing of the glaze slip is necessary to prevent settling, typically after every 20-25 pieces.

After dipping, excess glaze is allowed to drip off, and any remaining drips are smoothed out with a finger or tool.

For pieces dipped by hand without tongs, a brush can be used to touch up any areas that were missed or didn't receive enough glaze.

Reclaiming excess glaze by sieving it and adding water helps reduce waste and save money.