Glue - joining Knauf board to corflute

 
  Gremlin Assistant Commissioner

Hi All

End of year task is getting a lightweight and portable backdrop onto the baseboard; the backdrop (Corflute) also supports some Knauf board attached perpendicularly (that is, the backdrop is vertical and the Knauf is horizontal and used to support some lightweight scenery).

Some time back, I tried using PVA and two-part epoxy but found that it didn't make a permanent bond. I then tried Gorilla glue which did the job but, some months later, I have found that a slight twisting or bending action causes the bonded parts to cleanly separate - it appears that the Corflute is quite impervious to glue!  I also found the same problem with balsa wood glued to Corflute.

I am tempted to fix the Knauf board into position with pins and glue it with Gorilla glue, then horizontally drill a 5mm hole so I can glue a dowel in place as well.  Seems overkill, but it looks like mechanical bonding is needed in addition to glue.

Has anyone successfully glued Corflute to anything?

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  Harley Junior Train Controller

Location: Clergate, NSW
Hi All

End of year task is getting a lightweight and portable backdrop onto the baseboard; the backdrop (Corflute) also supports some Knauf board attached perpendicularly (that is, the backdrop is vertical and the Knauf is horizontal and used to support some lightweight scenery).

Some time back, I tried using PVA and two-part epoxy but found that it didn't make a permanent bond. I then tried Gorilla glue which did the job but, some months later, I have found that a slight twisting or bending action causes the bonded parts to cleanly separate - it appears that the Corflute is quite impervious to glue!  I also found the same problem with balsa wood glued to Corflute.

I am tempted to fix the Knauf board into position with pins and glue it with Gorilla glue, then horizontally drill a 5mm hole so I can glue a dowel in place as well.  Seems overkill, but it looks like mechanical bonding is needed in addition to glue.

Has anyone successfully glued Corflute to anything?
Gremlin
Hi Gremlin,

Unfortunately, a mechanical joint is almost unavoidable in your situation. Coreflute is made from polypropylene, which is notoriuosly difficult to glue, and the glues that do work, are often quite volatile, and may not be compatible which the extruded polystyrene Knauf board.

You might have some luck using a 3M VHB double sided tape. VHB stands for Very High Bond, and some variants of the tape are suitable for low surface energy applications like polypropylene. There is a 3M 'Scotch' branded tape available at Bunnings that appears similar if you wish to give it a try without commiting to buying a large roll of the good stuff from an industrial supplier.

https://www.bunnings.com.au/scotch-5cm-x-1-2m-extreme-double-sided-mounting-tape_p3962500

If you are not too far down the Coreflute road, perhaps you should consider using foamed PVC. It's very easy to work with, lightweight, cheap and easier to glue.

Regards,

Harley
  Booly Junior Train Controller

Try using selley liquid nails fast grab in the yellow calking tube ( make sure it's the one that's safe on foam ) , rough up the back of the corflute with some course sand paper and the foam to give it something to key to .
Hope this helps.
  Oscar Train Controller

Hot glue works. I tried some with corflute flat against the factory edge of the knauf board. The board was a full 600x1200x30mm thick and I glued a patch about 3 inches long then pressed on the corflute which was about 600mm square.  After an hour cure the join was solid, each piece holding the other at angles despite the small contact patch.  When tearing the joint apart a layer of foam was left on the corflute, so that was encouraging. I would've predicted the glue would've separated from the corflute. Anyway, the glue is stronger than the foam and it sticks to the corflute.

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