Bonding of edgings

The theme of “adhesives” is extraordinarily complex. In the OSTERMANN range there is a variety of different products available for the most diverse requirements. That’s why this answer only applies for a standard EVA hotmelt adhesive: The ideal temperature for this is about 190 – 210 degrees C in the gluepot, preferably higher rather than too cold, since the temperature decreases right up to the application roll.

Special tip: You should not rely on the temperature indicator in the display but should check the temperature in the glue pot and on the application roller regularly.

When edgings don’t stick it could be that the heating unit of the machine is defective. This happens sometimes even on new machines. In this case the required temperature of the hotmelt adhesive is not reached. It’s a good idea to measure the hotmelt adhesive. For this you can use for example an infrared thermometer, which can measure temperatures from -18 to +260 degrees C at the push of a button. It is important to measure not only the temperature in the gluepot but also the temperature where the glue is to be applied!

Special tip: If you do not have an infrared thermometer, our field service offers a one-off, non-binding measurement. For regular checks, we now have a suitable measuring device in our range.

If there is not enough pressure applied to the edging on the first roll and the joint is not closed immediately, then the edging doesn’t stick properly. The reason is that the adhesive is not fully in contact with the board. Even on the second roll the adhesive has then cooled down too much to spread sufficiently and make a strong bond between the board and edging.

Special tip: You can check the adhesive application and the roll pressure with our transparent test edging without primer. This test edging is available in 23 and 43 mm widths and in 0.4 mm thickness.

Real wood edgings in general have more residual stress. The adhesive thus has to achieve more. The edgings can still be bonded automatically with all standard hotmelt adhesives (EVA, PUR, PO), or manually with Kantol special glue, but more adhesive needs to be applied. In addition, all our thick veneers (1 and 2 mm) are coated with a bonding agent (primer). In comparison to wood veneer edgings without primer, primered edgings show far better bonding characteristics. For machine processing, we recommend a glue application of approximately 200 - 300 g/m2.

Special tip: With some glueing machines the roll direction can be reversed. This results in more adhesive being applied and so to better adhesion of real wood veneer edgings.

Our plastic and thick veneer edgings are always primed. The so-called primer is a bonding agent. which is responsible for a better adhesion between edging and glue. Whether or not primer was applied to an edging can be seen under UV light. Our thin veneers and end grain edgings have a wafer-thin fleece on the back instead of the primer. This ensures not only better adhesion but serves also as splinter protection.

Special tip: See for yourself and compare the chip pull after removing a veneer edge with and without pre-applied primer!

In most businesses EVA hotmelt adhesive is used and fulfils the requirements reliably. However, OSTERMANN experts recommend PUR adhesive because of its clearly better adhesive qualities (water resistance, thinner bond line, higher bond strength). Many businesses are concerned about cleaning the machine after using PUR, but the hotmelt adhesive gluepot is easy to clean after cooling with the help of the blue cleaner. However, you must not forget to do this.

Special tip: It’s also possible without the cleaner. Carefully remove the PUR residue, run the leftover edging through, until there is no more adhesive on the roll and then apply EVA glue to edging again.