The curing rate is 3 mm per 24 hours, so a 12 mm sealant joint will be fully cured after 4 days.
No. The 3 mm layer that is formed in the first 24 hours also acts as a barrier for the necessary air moisture. The curing process will proceed more slowly because the air moisture also has to penetrate this initial layer.
Repair work using the same sealant is not successful: the second sealant layer simply comes loose.
Correct. You should first cut away a layer of the old sealant and then apply new sealant onto the cutting surface (without using primer!). Only then will the adhesion process be successful.
How can I remove sealant residue?
Fresh residue can be removed using one of the cleaners listed in the Technical Data Sheet. Once cured, adhesives or sealants can usually only be removed by mechanical means.
If a sealant is paintable, does this mean I can use any type of paint?
Sometimes a sealant is merely paint-tolerant, i.e. the paint does not affect the sealant and vice versa. The Technical Data Sheet indicates which type of paint is suitable. Incidentally, a sealant joint should not be painted over. Unlike paint, sealant is generally elastic. This means that the paint will tear when the joint moves.
The sealant is not curing properly.
Possible causes: the temperature is too low, the sealant is enclosed without access to air moisture, or the environment is too dry.
The sealant I used in concrete joints is showing tears.
Some possible causes: the joint is too narrow or the concrete surfaces are too large. The correct dimensioning of joints is extremely important. A joint width of 3 millimetres should be used per running metre of concrete, e.g. a joint width of 18 mm for 6 metres of concrete. You must also use the correct sealant: a sealant that is too rigid (i.e. with a high modulus) cannot follow the movement of the joint. In addition, you must not apply an anti-adhesion layer to the underside of the joint. Three-point adhesion will also cause tears in the sealant.
The sealant joint is subject to loads from fork-lift trucks, which cause the sealant to be spread out from the joint.
It is also possible that the substrate is exerting too much pressure on the sealant joint, causing the sealant to compress and bulge out of the joint. This is caused by incorrect joint construction. The surfaces are too large. Additional joints should be created to improve the distribution of stresses in the substrate.
The 2-component sealant I used has not fully cured.
The hardener has not been mixed in properly.
The natural stone I used is showing stains near the sealant joint.
This phenomenon is also known as 'edge zone contamination'. The problem can be prevented by using a special sealant for natural stone.
How is it possible that Fireseal S protects against fire, yet is only permanently resistant to temperatures of up to +90°C?
In the event of fire (i.e. quickly increasing heat), Fireseal S is transformed into a rigid, heat-resistant layer to repel fire. The properties of Fireseal S as a joint sealant (elasticity, following movements) can only be preserved if the sealant is not permanently affected by extreme heat.
The sealant does not adhere (properly) to PVC windows.
An incorrect sealant may have been selected. In addition, the protective film on PVC windows produces static electricity upon removal. This causes loss of adhesion of the sealant. Wipe the PVC surfaces with a moist cloth after removing the protective film, allow the surfaces to dry, and then finish with sealant.
Is silicone sealant resistant to chemical substances? Which sealant is most suitable for applications involving chemical substances?
Silicone sealant is not entirely resistant to chemical substances. The silicone sealant Silicon 80 is resistant to the chemicals used in swimming pools. If the sealant will be subject to other chemical substances, such as motor fuels, it is preferable to use Floorseal. Always consult Bostik's technical specialists for advice in these situations.
In what types of packaging are your sealants available?
Our sealants are available in 290 ml and 310 ml cartridges, in 400 ml and 600 ml sausage packs, and in 20 litre and 200 litre barrels. The size of the packaging depends on the application method used.
Mould is growing on my SMP joint just one day after application. How is this possible?
This is not mould but the formation of crystals. Activities involving solvents were probably carried out near the SMP sealant joint on the same day that the joint was applied. As a result of a chemical reaction, crystals form on the sealant (these look like ice crystals). Once the sealant has fully cured, the crystals can be brushed away and the problem is solved.
The SMP joint is coming loose on the inside of the glass.
UV radiation reaching the sealant joint from the exterior (i.e. through the glass) causes loss of adhesion. Protect the sealant joint from UV radiation with glass Prep G.
The SMP joint shows yellow discolouration.
This probably concerns an interior application. A lack of UV light can sometimes produce yellow discolouration in an SMP joint. Work is underway to find a solution for this defect in a number of SMP-based products.
Can I use an SMP-based product to seal roof edging strips?
Preferably not. Elastoroof is better suited for this purpose. SMP-based products are sensitive to substances that may migrate from bitumen substrates into the sealant. This may result in brown discolouration and loss of adhesion.
During the sealing of a window, the sealant suddenly produced smoke or vapour. What is the cause of this?
Two different types of sealant were used: acid and alkaline sealant. If these two types of sealant come into contact with one another when 'fresh', a severe chemical reaction occurs that produces smoke or vapour. Request advice immediately!
Do you have an FDA kit for this sealant?
FDA stands for Food and Drug Administration. An FDA kit signifies official approval that the product (i.e. the sealant) can come into contact with foodstuffs and other items. Many sealants produce stains or lend a peculiar taste to food. The sealant must be chemically inert and may not introduce any foreign chemical substances into the food. Bostik recently obtained approval for a particular sealant to be brought into contact with food. Contact Bostik for more information.
How do I apply sealants with a gun?
