problems using roo clear with melamine

I just tried gluing up a quick sample joint using biscuits and RooClear on 5/8" melamine. The two pieces were about 10"x16", with the joint along the longer dimension.
The joint was a 90 degree "L" with the edge of one piece joined to the melamine face of the other. I put the glue on the edge of the one piece and in both sets of biscuit slots, then clamped the two pieces together at about the same pressure I would use with yellow glue and plywood. I left the piece to dry at room temperature for about 18 hrs.
I then tried breaking open the joint for testing purposes. The joint broke when the biscuits pulled out of the edge (rather than the face), taking some of the particle board with them.
However, the real problem is that it appears that the particle-board/melamine bond was basically non-existant (there are no particles stuck to the melamine).
Anyone have any ideas why it failed? Other comments on this glue have said that it would pull the melamine off the face rather than fail at the glue line.
I'm re-trying the joint with no biscuits, just glue. Have to say that I'm not very impressed so far.
I've emailed the manufacturer to get their comments.
Chris
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For best results, biscuits need to be glued with a water based adhesive.

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Leon wrote:

Roo is water-based, and the biscuits seem to have stuck reasonably well. (They took chunks of particleboard with them when they pulled out.)
My complaint was that the Roo didn't stick to the melamine (which it is supposed to do).
Chris
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I see, I thought it was a Polyurethane glue. I really have not heard that any water based glue sticks to a non porous surface like Melamine.
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Ok, now I see that you are indeed using the correct glue, I have no idea why your set up did not work unless you have a gap on the glue line.

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In a previous box-building lifetime, I experimented a lot with melamine joinery. My base material was 5/8 melamine 120 gram both sides. The '120 gram' is a number indicating the thickness. The higher the number the better the grade. A good quality shop uses 120. The dreck you find at RTA-type suppliers is often as low as 60. That makes a huge difference in how well the melamine itself adheres to the substrate. I also made standard L-shaped pieces for testing purposes. My tests were also taking a close look at how quickly and how accurately a box could be assembled, without sacrificing the integrity of the box. Introducing the use of low-root, nibbed screws and ways to hide them. I tried everything I could think of. I thought the best way was to use a rabbet or a dado, sunk in only about 1/8". To cut those edges clean and accurate required way more set-up time than I was prepared to invest. Scoring blades and dado-stacks are a bitch. PB to PB glues really well with basic white glue, but now I was clamping. Tried RF induction, which still required some clamping. Not efficient enough. Then I tried some lacquer-based adhesives, designed for use with melamine. Nice results, but only up to a point. That melamine is attached to the PB with minimal strength. When the joint failed, it did so catastrophically. No give. Besides, it simply wasn't that strong. Never did have time for biscuits. Too damned complicated in production, and PB is PB, no matter what. Then I tried mechanical fastening. Confirmat screws are very strong, but offer very little advantage over a #8-2" low-root screw. Of course, what I got was a very strong joint, but with screw holes. Solution? Cover the whole side of the melamine cabinet side with a sheet of PF PLAM, which you can get in the same texture as melamine. Of course, you only do that to those cabinets which you can see. When building oak cabinets, use a sheet of 1/4" veneer ply to cover your sins. Hiding your tracks also allows you to shoot nails to hold things in place while you drill (air drill, they stop nice and quick) 1/8" hole with a brad-point. Wurth makes nice ones. Melamine to melamine---> mechanical fasteners. Everything else is a waste of time.... but that's just my opinion.
r
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