All (technical) advice and treatment and the possible applications regarding the products on this website are given without obligation, and to the best knowledge and effort, as well as the current state of technology, without an obligation to create results and without any liability. We recommend that the prospective user determines the suitability of our materials and suggestions before adopting them on a commercial scale.

A1 Top layer

Using our A1 Triaxial fabric is an excellent way to strengthen A1. Two or more layers of A1 Triaxial fabric laminated in the A1 creates strong A1 objects. Unlike materials such as polyester and epoxy, the A1 does not absorb the glass fabric but clamps it between 2 layers of A1. The A1 in this case acts like a sandwich with the fabric sandwiched. That is why it is important to use sufficient A1 between the different glass fabric layers. Working too ‘dry’ results in a less strong end result and gives a greater chance of delamination (release of the different layers), which we want to avoid. Also on the very first layer before the 1st layer of glass fabric is applied (more than) sufficient A1 should be used to create an adhesion between the first layer and the glass fabrics.

In addition, we advice to apply the different glass fabric layers (alternating with A1 layers) directly after each other. Work wet in wet to get an optimal bond between the different layers.

A1 is known for its freedom of form and the post-processing of an object made with A1 often gives spectacular results. Our suggestion is a thickness of the top layer of at least 2 mm in order to give enough mass to the A1 to maintain sufficient adhesion on the underlying layer and sufficient strength to withstand weather influences such as UV radiation.

Top layer in a mould
When working in the mould, the 1st layer (called top layer) of A1 is important, as this is ultimately the visible layer. By using the A1 Thix A you can turn the A1 into a beautiful pasta. Because of the thickening, the A1 stays in place, even when working in a mould with vertical parts. To ensure this top layer has enough thickness we suggest the following working method:

  • Mix the A1 Liquid with the A1 Powder until a smooth mixture is obtained.
  • Add to the A1, mixture if desired, pigment in the right colour and/or other materials such as dried sand or metal powders.
  • Add A1 Thix A until the desired thickness (viscosity) is reached. The maximum percentage of A1 Thix A you can add is 2%. Adding more will eliminate the effect.
  • Apply the A1 top layer to the mould with a brush, for example. Keep a layer thickness of at least 1 mm.
  • After gelling of the top layer (normally between 20 – 30 minutes) we advise to continue working the next A1 (glass fiber reinforced) within 1 hour to keep the adhesion optimal.

A1 is not a coating material to protect other materials against weather influences.

Regularly we are asked whether A1 can be used to weatherproof a sculpture made of plaster, clay or concrete blocks. Unfortunately, this is not recommended as A1 absorbs (to a limited extent) moisture and will transfer this moisture to the material that has to be made weatherproof. These materials eagerly absorb this moisture from the A1 without transferring it back to the A1 in dry conditions to evaporate.

This creates spots with a high continuous moisture load that weakens the connection between the A1 and the material it covers. At higher temperatures, the water evaporates or at low temperatures the water freezes. This creates so much pressure between the different layers that the A1 layer loses its bond with the underlying material. That is why we advise to only use (glass fabric reinforced) A1 or underlying materials that do not absorb moisture.

When applying 1 layer of A1 of 1 mm thickness you will use 1.75 kg A1 per m² (1 liter A1 = 1.75 kg).

In a mould you normally work with a first layer of 1 to 2 mm. Next, we advise to use 3 layers of A1 Triaxial fibre. In order to achieve this will have to apply 4 layers of A1 of 1 mm. Normally in a mould we thicken A1 for the first layer with Thix A. Make sure this layer is hardened before applying the next layers to avoid print through of the A1 Triaxial fibre. Use 1 layer of A1 between your hardened first layer and the first layer of A1 Triaxial fibre in order to make a proper bonding.

As an example needed for a project of 5 m²:

  • 2 mm 1st layer
  • 4 layers of 1 mm A1 in order to apply the 3 layers of A1 Triaxial fibre

Total 6 mm of A1 x 1.75 kg per layer x 5m² is 52,5 kg of A1, consisting of 17.5 kg A1 Liquid and 35 kg A1 Powder. Be aware that this is an indication and not a general rule.

Sealer and Coatings

A1 Sealer is enough but we advise to check periodically the surface on damages so it can be repaired. Depending on the area where the products are placed a new layer of sealer might be necessary every 3-5 years. The Sealer is available in Matt and Satin. High-gloss is not available.

A1 Top Finish is a 100% vapour permeable, high-quality waterborne impregnating agent based on silane/siloxane and penetrates deep within the surface and leaves a long-lasting water repellent effect. We suggest to add one layer of A1 Top Finish on the layers of A1Sealer PLUS to achieve extra water repellent effect and maintaining a damp open coating system.



The A1 Sealer PLUS is not waterproof, but breathable. The brown colour is probably caused by the moisture in the soil. Two layers of A1 Sealer PLUS is usually sufficient, but with prolonged moisture loading, which is the case here, there is a risk of discolouration.

We recommend reapplying the A1 Sealer PLUS every 6 years. Furthermore, we recommend that you check the A1 object annually for possible damage to the A1 Sealer PLUS so that it can be repaired immediately. This inspection is also a good opportunity to clean the A1 object if necessary.


Poraver (expanded glass) can be used as a filler for A1. This is a recycled lightweight glass ball that allows you to achieve a large volume gain. Add the grains little by little to the A1 base. Another good and inexpensive filler medium for A1 is dried (silver) sand. (available in the building materials department in your local DIY shop). The choice of filler depends on your preference in terms of weight, desired appearance and cost.

A combination of fillers and/or pigments is also possible.

First mix the A1 Liquid (1 part) with the A1 Powder (2 parts). Then gradually add the filler to the A1 (maximum 2 parts). Add A1 Diluent if desired. We recommend adding a maximum of 0.67 kg fillers per kilogram of A1 created, whereby the ratio is 1 part
A1 Liquid, 2 parts A1 Powder and 2 parts filler (all by weight).

The colour difference can be explained by the presence of water in the object just after unloading. The water in the A1 liquid reacts with the A1 powder, but part of this water remains behind as residual moisture. Over time, residual moisture will also evaporate, resulting in the A1 object becoming lighter in colour. This is especially visible in combination with sand such as you use.

A solution could indeed be the application of a sealer or transparent coating, which will again increase the colour intensity. Naturally, there will also be more shine. Let the A1 object dry thoroughly before applying the coating because the moisture still present in the A1 object at higher temperatures (for example due to the sun) will damage the coating.

Another solution can be to use a very small amount of pigment to give it a slightly stronger color.

The solution could also be to put the image outside without a coating. A very thin top layer will be weathered by UV, so the sand will come to the surface more, which will result in a more intensive colour. Light sanding unfortunately works a little less because we see it becomes lighter in colour. Careful sandblasting would be possible again.

Note: we recommend using 1 part A1 liquid, 2 parts A1 powder and a maximum of 2 parts sand.


It is possible to use pigments from other suppliers to colour A1. In some cases, these pigments can affect the quality of the A1, ranging from slowing down/blocking the
curing process to decreasing the weather resistance. Hence our advice to test this in advance.

The base colour of A1 is ivory white. If desired, we have A1 suitable pigments in 10 colours with which the A1 can be coloured through and through. These pigments are highly concentrated and are added up to a maximum of 2% to the A1. Often a lower dose is sufficient to achieve the desired result. The A1 Pigments can be mixed with each other so that almost all RAL colours can be made.

A1 Triaxial fibre

A1, unlike polyester, does not absorb A1 Triaxial fibre but clamps it in between the different layers of A1. That’s why our glass fabric has an open structure that allows the different layers of A1 to connect to each other and to clamp in the A1 Triaxial fibre.

The best time to start laminating over the top layer is when it is drying but still feels slightly moist. immediately after the set time has expired. The best result is achieved when the laminating layers are applied wet to wet. An advantage of A1 is that after a few days you can still apply A1 with A1 Triaxial fi bre with a good adhesion. However, the substrate must first be coated with a wet layer of A1 before the A1 Triaxial fi bre can be applied.

Even with larger surfaces it can happen that the A1 already reacts (is hard) before a new layer of A1 Triaxial fi bre can be applied. This can be solved by applying a new thin layer of A1 or by slowing down the reaction time of the A1 using A1 Retarder.

Natural fibres are offered as an alternative to glass and basalt fabrics. A major disadvantage of these fibres is the tendency to absorb and retain moisture, which disturbs the moisture balance in the A1. This moisture absorption can also cause fungi to develop and eventually affect the A1 object. For outdoor applications, the use of natural fibres is therefore not recommended.

Sawing through a form

A1 has a processing time of about 20 – 25 minutes, after that the material is dry but still vulnerable. The advice to be able to saw and/or drill A1 properly is about a week as the A1 is (almost) finally cured. Sawing/drilling after 1 day is possible however be careful as the A1 object is not completely cured. You can use any sawing machine for this. Of course there is a difference in quality and skill of the machine. A water saw table or a dremel often give a nice result.
If you are not using hard fillers like sand it’s possible to trim with a jigsaw machine with a cutting blade for metals. Another option is a multi tool.
If the material contains sand you need a cutter for tiles or similar. For small parts a Dremel multi tool will work as well.

A1 and water - Moisture control

If the A1 object is constructed in such a way that the splash water can easily drain off and in combination with a good coating, we do not expect any problems. In places where the splash water can collect, we advise not to use A1.

We do not advise you to use A1 because A1 cannot stand permanently under water fo a long period, as A1 is vapour permeable.

Be careful as the soap might react with the A1 or more likely the continuous water beneath the soap which is entrapped between the soap and the A1 soap holder will affect the A1.

A1 wants to breathe and A1 attracts moisture and also releases it during dry periods. Therefore, the urgent advice not to disrupt this process by using a non damp open sealing paint or coating. The moisture still present in the A1 is converted into water vapor during warm periods and this can damage the coating system or the A1 top layer. A1 objects that are also not able to ventilate on the inside because of the use of, for example EPS, are extra vulnerable.

During the production process, moisture in the A1 liquid reacts with the A1 powder. A part of the moisture remains behind (residual moisture). Therefore, before an object is placed outside, it is important to make sure that the residual moisture has disappeared from the product. The duration of this depends, among other things, on the construction of the A1 object, the thickness of the laminate, the humidity present and the temperature of the storage location. Our advice is to give the A1 object the chance to evaporate the residual moisture in a covered area with room temperature for at least 7 days. At that time, the coating can also be applied.

A1 can withstand rain showers or an environment with a higher moisture load. In a situation where the A1 object is (very) long exposed to moisture, without the chance to dry again regularly, the top layer can become softer and in extreme cases even loosen from the underlying layers. That is why our advice is to ensure that (rain)water can always drain off the A1 object easily. Provide sufficient slope and avoid horizontal or badly sloping parts in the A1 object.

Our tests show that A1 objects can be placed outside for a long time with only a limited change on the outside. To extend this period by many extra years, we recommend applying a coating. This coating protects the A1 object because it absorbs the influence of weather conditions. Because A1 is a material that absorbs and releases moisture (breathable material), it is important to ensure that the coating system also has a breathable effect. The A1 Sealer PLUS is suitable for this, but also many wall paints such as KEIM Soldalan.


Very occasionally we come across A1 projects where the water can collect in. As long as this place is provided with sufficient protection, it will not be a problem for the A1 for a few days. For a longer period of time, this is something we really do not recommend. Similar to what we sometimes find on construction sites where A1 panels are stored before being mounted with the panels facing outwards with the wrong side up. This gives the rainwater every chance to collect and, because often no coating is applied to the rear, the water has every chance to penetrate into the A1. Constructively, this is not a problem for the A1 over a short period, but on the visible side, the places where the moisture has penetrated will soon be visible, even after it has dried.

A1 is excellent to use in combination with a large number of filling materials. It adheres excellently to, for example, wood, textiles and chicken wire. It is possible to add almost all small ground materials to the A1 mixtures, creating special shapes in appearance and structure.
For A1 objects that are placed outside, carefully consider beforehand whether this combination of materials also works well here. For example, we know that wood attracts moisture via the A1 and can even expand, causing the A1 layer to crack. Chicken wire will start to rust due to the moisture present in the A1 and this creates traces of rust in the A1. We encountered A1 objects where hydro grains were mixed in the A1 because it gave a nice structure. Subsequently, these hydro grains absorbed so much moisture that the surrounding A1 became soft and the top layer of A1 with hydro grains subsequently separated from the underlying glass fabric reinforced A1 layers.

Only use filling materials that do not absorb moisture or that will not corrode due to the present moisture. We have had good experiences with materials that do not absorb moisture and rust, such as granite, sand, EPS (Styrofoam) and aluminium.

Reinforcement materials and inserts required for mounting can cause problems in outdoor situations when these materials absorb moisture such as wood. Better use aluminium, stainless steel, EPS or pre-produced reinforcement profiles or backs of A1.

Inspection & Maintenance

Even if the perfect A1 object has been made, it can happen that due to an external influence such as a collision, a storm or a very long period of moisture exposure, the object is (slightly) damaged, for example, at the coating or the A1 top layer. Therefore, inspect the A1 object for damage at least once a year. These can often be remedied quite easily.

With prolonged and intensive UV and moisture exposure, coating and paint systems require regular maintenance. From our tests we see that (particularly on the sunny side) the Sealer PLUS is also subject to erosion and as a result the protection of the A1 decreases. On our North side and in particular on the A1 objects placed close to the ground, we see an increase in alga deposits on the test panels. Cleaning the A1 object at least once a year (soft brush) and applying a new coating every few years provides extra protection for the A1 and thus extends its lifetime.

Magnitude of the same A1 panel after reaplying A1 Sealer PLUS.
Magnitude picture of A1 panels with A1 Sealer after 4 years on sunny side.
Magnitude picture of A1 panels with A1 Sealer after 4 years on sunny side.
A1 object placed on the ground without any maintenance.
Same object after cleaning and applying layers of A1 Sealer PLUS.


A1 is a mineral based product and will change aesthetics under the influence of UV and moisture. A1 objects that are not protected and placed in an outdoor environment will quickly lose a fraction of their top layer (is a fraction of a mm) with (often) the result that the object becomes more intensive in colour. Also after a rain shower A1 objects absorb moisture and therefore become darker in colour to become lighter in colour during a dry period. Accept A1 is a natural material and that these aesthetic changes are part of it. If the A1 object must remain colourfast, a coating or paint system can be a solution.

A1 panel directly after demoulding.
A1 panel after 5 years of weather exposure.
A1 panel with sand directly after demoulding.
A1 panel with sand after 5 years of weather exposure.


We would not advise you to use A1 in a plaster mould as there will be a very strong bond between the A1 and the plaster and you will most likely not be able to get the A1 loose from the plaster mould.

We would advise you to use a silicone mould instead of the plaster mold. Due to the minimal expansion of A1, the A1 will press into the silicone mould and you will get an exact impression of the mould.