Poor Adhesion After Edging MDF

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Why has the edge come off this MDF? Maybe it's the glue, maybe it's the method... May 10, 2005

We had a job in oak on MDF and had to edge it. After a couple weeks, the edge is coming off! Is it the glue? The edge? Our edge bander?

Forum Responses
It has to be your glue or process. MDF has good adhesion. I don't have edgebanding equipment, but I have glued piles of wood to MDF and also glued MDF to MDF using aliphatic resin (yellow glue).

When the piece came off, was there glue left on the banding, or was it all stuck to the MDF? My guess is that it was poor adhesion to the oak strip - could be an issue of temperature of the hotmelt, condition of the band (dull blade will cause glazing on the wood that won't accept hotmelt well), or incorrectly adjusted pressure station. Good idea to use a primer on difficult materials to ensure adhesion. Dorus makes a primer, or dilute white glue 50/50 or so with water.

This is not so unusual a problem with MDF in commercial work. Priming the MDF is the standard solution. Yellow glue should do just fine.