Fireclay clay for oven plaster: application

For centuries, fireclay clay has been a reliable material for creating and maintaining ovens. Because of its special qualities, which include outstanding heat resistance and durability, it is the best material to use for oven plaster. However, what precisely is fireclay clay, and why is it ideal for this use?

The materials you use to plaster an oven must be able to withstand high temperatures without breaking down or losing strength. Herein lies the power of fireclay clay. This particular variety of refractory clay is ideal for building a robust, heat-resistant plaster layer because it can withstand the extreme heat generated by an oven.

In this post, we’ll look at the benefits of using fireclay clay for oven plaster, how it’s applied, and why it’s a wise option for anyone trying to make sure their oven lasts a long time. Whether you’re renovating an existing oven or building a new one, knowing how fireclay clay works in oven plaster will help you get the best results.

Application in practice

Chamotte

The color of fire clay is earthy gray.

• Fireclay clay, as such, does not exist in nature at all, since it is a crushed firing product, which, compared to other building materials, has a very low price. That is, for this they use kaolin or white clay, which is fired, and then crushed into powder and hydromica is added. Such a powder can have a coarse or fine fraction, so coarse-grained material is sometimes used for decorative finishing of the same stoves or buildings.
• Considering the fact that fireclay is diluted with ordinary water for use, the storage instructions provide for its packaging in waterproof bags and storing in a dry place. This material is used both for laying bricks and for plastering them, only the latter method requires some change in composition.

Plastering work

Note: Dust cannot be tolerated in this type of work with refractory materials, nor in any other work of a similar nature. This implies that the stove’s surface that will be plastered needs to be spotless, particularly for older buildings where the finish has already been chipped off. Primers are usually not used here, but dust is carefully brushed or broomed away, and sprayed with moisture before finishing.

We will make the final solution in the following proportions in order to prepare it:

• Fireclay – 2 parts;
• Portland cement – 1 part;
• Quarry sand – 7 parts;
• Water – guantum satis (as much as needed).

This is the best ratio for hot structures; you might receive slightly different proportions from someone else, but they won’t differ all that much. It is best to make the mixture in a specific order because doing otherwise could result in a composition that is up to 30% stronger than it was originally intended to be. To put it another way, you should dilute the cement until it is the consistency of thick milk before adding the remaining ingredients.

Furthermore, the sand must come exclusively from a quarry; if river sand is used for the solution, the mixture will not have the right viscosity and will float.

In order to obtain the required plasticity, refractory clays had to be specifically soaked in water for at least three days prior to use; however, contemporary products enable you to skip this drawn-out procedure. All you need to do is fully combine the ingredients in the container; a rough blend can be achieved using a shovel or hoe, but manual mixing yields the best results. The resulting mixture will be of excellent quality.

As level stove walls are obviously essential to the success of the design, you will need beacon perforated profiles and perforated corners for plastering. In this instance, two profiles will be sufficient for a single plane (wall); in other words, two support points are required for the mortar to be level with a rule.

As seen in the above photo, these can be two corners at the edges of the structure, but this is usually not convenient and the beacons are glued directly to the plane; the corners should still be installed for rigidity.

These profiles are installed strictly in accordance with the plumb line or level; however, these leveling tools will not be sufficient if there are more than two profiles. Use a long building rule or pull the threads vertically and diagonally for this. Only when the rule is applied across the beacons in a simultaneous manner to each profile will the ideal plane be obtained. It is necessary to try both horizontally and diagonally.

There will probably be firebox or ash doors on the wall, so the placement of the beacons should match the length of their extension. That is to say, when laying the stove, this issue should be taken into account because the plane formed by the profiles should be on the same level with such doors.

If you haven’t done this beforehand, you might need to push or pull out the ash pit or firebox in order to make the entire wall seem reasonably attractive.

Many stove manufacturers take note of the fact that when plastering is done "hot," it remains flawless after drying. Should comparable work be completed "cold," the wall will eventually develop tiny fissures all over it.

A spatula is used to smooth the clay.

The clay-containing solution turns out to be highly viscous; as a result, unlike a typical cement-sand mixture, you won’t be able to pull it together with a rule; instead, the composition will adhere to the metal. Even so, you can effectively level with this tool; in general, you will still obtain a flat plane, albeit one that has a lot of flaws like cavities and cracks. Afterwards, use a wide spatula to finish leveling, covering all the nooks and crannies while also smoothing the surface.

Plaster should be added to the spatula in order to level the plane because the solution that is left on the wall after the rule is pulled will not be sufficient. Naturally, while doing this kind of work, you will go against the strict vertical because the spatula will smooth in an arbitrary manner without any supporting structures.

Consequently, utilize the building rule once more after smoothing and sealing the sinks. Pull the mixture along the beacons to remove any excess solution; where it is absent, gaps will appear. Repeat this process multiple times until the finish quality is to your satisfaction.

The stove’s ceramic tiles

Finishing ceramic tiles can be placed on top of stove plaster if desired, but the stove’s heating will not change, so a special glue will still be required. Traditionally, this was done with a cement-sand mortar mixed on brine, which caused the seams to turn white. Nevertheless, specialty mixtures are now available in the construction market. The majority of artisans concur that CERESIT CM-117 should take the lead in this situation.

For plastering ovens, fireclay clay is a useful and long-lasting material that provides exceptional heat resistance and a natural appearance that highlights the allure of traditional masonry. When used properly, it not only keeps the oven from breaking from extreme heat but also increases its efficiency by holding onto the heat. When building a new oven or renovating an old one, employing fireclay clay guarantees a durable, practical, and visually appealing result.

For oven plastering, fireclay clay is a great option because it’s heat resistant and durable. Since it’s a naturally occurring material, it can tolerate high temperatures, which makes it perfect for fireplaces, stoves, and other heating structures. Applying fireclay clay correctly guarantees a durable and dependable finish that protects and improves the appearance of your oven.

Although the application process is simple, paying close attention to details is necessary to get the best outcomes. The plaster needs to be mixed, layered, and dried properly in order for it to stick well and work efficiently over time. A properly plastered oven improves the safety and aesthetic appeal of your house, so it’s worth taking the time to do it right.

It makes sense to use fireclay clay in any construction or renovation project involving your oven. It’s a useful, effective material that has endured because it combines strength and beauty in a way that many contemporary materials just can’t match. Whether you’re installing a new stove or giving an old one a makeover, fireclay clay is a solid option that will last for many years.

Video on the topic

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