Fireclay mortar does not stop and breaks out

The adhesive behavior of fireclay mortar differs from other types of mortar. The ceramic setting is very dependent on a controlled heat supply and uniform external conditions. During processing to first burnout, the mortar often does not last when experiencing incorrect or rapidly changing changes.

Fireclay mortar is sensitive until properly cured

Fireclay mortar has no hydraulic binder such as cement. To cure properly, it must be processed under stable conditions and brought to setting. The most common reason why fireclay mortar does not last is external changes to setting and incorrect temperature delivery to achieve setting.

When processing fireclay mortar, a wet well-watered environment is important. Only then do the fireclay bricks make a good holding partner and bearer. When inserting the press joint technique should be used. The joint width is ideally no more than three millimeters.

Possible causes of non-retaining fireclay mortar

If the fireclay mortar does not last, the following factors should be checked:

  • Are all application surfaces wet?
  • Are the outside temperatures between ten and twenty degrees Celsius?
  • Is the humidity on average (sixty to seventy percent)?
  • Is not the workplace warmed up by solar radiation or a radiator?
  • Was the mixing ratio adhered to in accordance with the manufacturer's instructions?
  • Has the mixture already been carried out homogeneously in the dry state?
  • Does the fireclay mortar have an aluminum oxide content of over thirty percent?

Foreign materials do not stop

In many cases, other materials such as metal pipes and aprons are used in private furnace construction. Fireclay mortar usually can not form a durable and stable guide bead. When foreign materials come into direct contact, special transitions and, if necessary, additional sealing and support structures should be implemented.

Finer and smaller cracks in the fireclay mortar can be filled. To ensure the shelf life of the new entry, a similar gradual heating should take place after drying out, as is required for the first firing. During the construction period of a barbecue or stove with fireclay extreme seasons and weather conditions should be avoided. The early summer is well suited and any solar radiation should be held by shading until setting.

Tips & Tricks

Buy fireclay mortar produced in Europe, ideally up to 1300 degrees Celsius capacity. No-name products from outside Europe are often stretched with unsuitable sands.

Artikelbild: Nagy-Bagoly Arpad / Shutterstock

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