Laminating MDF?

[rschissler]

I recently laminated plastic laminate to  plywood, using Weldwood Contact Cement, with good results.  I've been trying to do the same with MDF, but I'm up to four coats of contact cement on the MDF now, and it's still absorbing all the cement, not leaving a glossy surface to where I can apply the laminate.  Am I missing a step, or do I need to just keep applying more and more coats of the cement?

[Cooler]

Does it feel tacky?

Particle board is the standard substrate for Formica which is almost always adhered with contact cement and particle board generally absorbs more than MDF.

If the boad feels tacky, I think you are good to go as long as covering layer is also coated with contact cement. Make a test piece to be sure.

[jteneyck]

Did you sand the MDF?  Solvent based contact cement shouldn't absorb too much into MDF unless you first sanded it.  

For small jobs I now use 3M's rattle can contact cement.  It might be a solution for the problem with the panels you already have coated.  For any uncoated panels you still have to process, you might try putting on a coat of Sealcoat shellac first, and then your choice of contact cement after it's dry.  

John

[AgGEM]

Did you sand the MDF?  Solvent based contact cement shouldn't absorb too much into MDF unless you sand it.  

For small jobs I now use 3M's rattle can contact cement.  It might be a solution for the problem with the panels you already have coated.  For any uncoated panels you still have to process, you might try putting on a coat of Sealcoat shellac first, and then your choice of contact cement after it's dry.  

John

I think that John is correct about using the aerosol can of CC. I think the cement starts to dry between the nozzle and the work, as it fly's through the air. I think that is desirable. I have no evidence to back this up, just a hypothesis on my part.

[rschissler]

Yes I sanded it.  No it doesn't feel tacky, except the joint where I glued two pieces of MDF together.  Maybe a coat of glue size (water thinned wood glue) would be best in the future? Except, wouldn't the moisture from it be bad?

At this point, I'll try another coat or two, or three.

[MstrCarpenter]

White glue holds plastic laminate to MDF. It has to be clamped though. Some shops I did installs for just put more sheets of MFD on top of the stack of glue-ups. That was back when off white cabinets with oak molding for finger pulls were popular. They also did fake wood grain with routed designs on the face; which was in before thermo-foil took over.

[Cooler]

White glue holds plastic laminate to MDF. It has to be clamped though. Some shops I did installs for just put more sheets of MFD on top of the stack of glue-ups. That was back when off white cabinets with oak molding for finger pulls were popular. They also did fake wood grain with routed designs on the face; which was in before thermo-foil took over.

White glue or yellow glue.  It seems to hold tighter than contact cement.  We had formica lifting in the corner of a desk at work.  I squirted yellow glue under the delamination and used a vacuum cleaner to suck it further under the formica.  It has been 15 years and it is still holding (though I wish it was not.  New furniture would be nice about now.)

And yes, it either has to be clamped or weighted down.  That is the primary advantage of contact cement--it's fast.  You can roller it down and you are done.

[rwe2156]

I've never sanded it and never had an issue. I usually use 2 coats, tho.  You have to wait for the first one to dry completly.

I would think sanding it would allow to much adhesive to be absorbed into the panel.

Using PVA glue IMO to do that properly you need vacuum clamping.

But what do I know..........

[rschissler]

I sanded it because there were saw marks showing. I cleaned it well after sanding  After putting on five coats of contact cement, it was good enough to apply the laminate.  It seems to be a successful hold.

[Cooler]

I've never sanded it and never had an issue. I usually use 2 coats, tho.  You have to wait for the first one to dry completly.

I would think sanding it would allow to much adhesive to be absorbed into the panel.

Using PVA glue IMO to do that properly you need vacuum clamping.

But what do I know..........

You do need pressure across 100% of the surface for a good bond.  Easy with a vacuum bag; difficult with clamps or weights.  I have found that putting a piece of 3/4" stock over the lamination and adding weight evenly across the surface works.   I use plates from my weight lifting bar for this.  Sandbags work well too and are cheaper (but hard to move around at 80 pounds each).