Melamine faced (one side) Chipboard - will it warp?

[Paul Carson]

Hello,


I need to make a large drafting board 49’’ x 36’' (c.1250mm x 900mm) which I need to remain stable and flat.


I'm considering using 18mm melamine faced chipboard (particle board) which I will edge with beech.


Is this stuff stable ?
Will it move or warp ?




Thanks, Paul

[Mike Cutler]

If not properly supported, yes it will warp, or I think sag would be the better term. It is a stable material, but it needs support.

[Wayne Lomman]

Yes it will warp. There is a sealed side and an unsealed side. Warping is inevitable as with a table if you don't polish the underside.Use melamine that is coated both sides. Cheers

[Marty Schlosser]

Could he not simply apply a topcoat of varnish or other similar product to seal the underside? It'd still have to be supported somehow... but his warping problems due to dissimilar coatings would be negated.

[Gerry Grzadzinski]

Yes it will warp. There is a sealed side and an unsealed side.

No, both sides are the same. If one side was different, it would warp badly before you even used it.
As Mike said, sag is probably a better term.

[John Blazy]

I've been using two sided melamine for about 27 years or so, and still use it for its flatness and incredible versatility, but never even heard of one sided. During its pressing, the melamine faces seal and balance the panel so well, I can't see the reason for one sided sheets. Polyurethane construction adhesive literally welds to the melamine faces, so lack of one face for reasons of gluing something to it are beyond me. I have veneered exotic veneers directly to melamine with long lasting results (using - you guessed it - PUR glue).

I use melamine now for flat epoxy / urethane layups of high-tech composite laminates due to flatness and easy clean up (nothing sticks besides PUR), and can guarantee you that one sided melamine, even sealed with a finish will absorb moisture through the finish via osmosis and warp (concave on the melamine side sue to swelling on the opposite side), unless you use epoxy as the seal.

If you have to use one sided melamine, (even two sided) I would glue it up as the face skins of a torsion box for guarantee against warping. My nine foot long primary laminating table is torsion box with 1/2" melamine skins (cores glued with PL Premium PUR) and after 20 years is still absolutely dead flat, even though supported across only two points.

Go with two skins of 8mm thermoset melamine (not vinyl ultrafoil) with about 1" or more high cores glued with PUR, and you'll have a forever table.

[Jamie Buxton]

... (using - you guessed it - PUR glue)....

Wait, what, PUR glue for veneering? The only PUR glue I've noticed is sticks for hotmelt glue guns. It lays a bead that wouldn't work for veneering. I did a quick google, and found mentions of PUR sheets for laminating, but it seems it would require a big hot-melt veneer press, which is something no small shop would have. Am I missing something here? How do you do PUR lamination?

[John Blazy]

PUR stands for polyurethane, like Gorrilla glue and PL Premium Construction adhesive in tubes (my favorite for all adhesion apps - veneering, filling and bonding to end grain apps like solid wood to plywood edges, particle board, MDF edge, metal to wood, stone to wood, etc).

[Ken Combs]

I think it will warp, in addition to the 'sag' mentioned.

Years ago I was doing solid surface veneer, Swanstone, 1/4" material. They sold pre-veneered countertop material. 3/4HD particle board with 1/4" SS applied to one side. It would always warp if we didn't apply a laminate to the bottom.

Likewise, if making up a wider bartop, it would warp in a couple of days if not fastened down. I think moisture absorbtion in the unfaced side was the cause.

[jack duren]

I've been using two sided melamine for about 27 years or so, and still use it for its flatness and incredible versatility, but never even heard of one sided. During its pressing, the melamine faces seal and balance the panel so well, I can't see the reason for one sided sheets. Polyurethane construction adhesive literally welds to the melamine faces, so lack of one face for reasons of gluing something to it are beyond me. I have veneered exotic veneers directly to melamine with long lasting results (using - you guessed it - PUR glue).

I use melamine now for flat epoxy / urethane layups of high-tech composite laminates due to flatness and easy clean up (nothing sticks besides PUR), and can guarantee you that one sided melamine, even sealed with a finish will absorb moisture through the finish via osmosis and warp (concave on the melamine side sue to swelling on the opposite side), unless you use epoxy as the seal.

If you have to use one sided melamine, (even two sided) I would glue it up as the face skins of a torsion box for guarantee against warping. My nine foot long primary laminating table is torsion box with 1/2" melamine skins (cores glued with PL Premium PUR) and after 20 years is still absolutely dead flat, even though supported across only two points.

Go with two skins of 8mm thermoset melamine (not vinyl ultrafoil) with about 1" or more high cores glued with PUR, and you'll have a forever table.

One sided melamine has been around as long as I can remember. cheaper than two sided if your going to cover with veneer,laminate,etc.

[Cody Jensen]

Particle board has no preferred direction, so I can't see how it would warp. I have seen many cheap desks/tables that have protection on a single side and the other is unfinished. I can't see it moving in an interior application. I think sagging is the issue, not moisture.

[Wayne Lomman]

Ken, your experience describes the effect exactly. We are offering advice for a drawing table which generally means something reliably flat.

They gave up selling single side melamine in Australia years ago because even the cheap shops got sick of the complaints. Cheers

[peter Joseph]

I built a watchmaking desk years ago with the material you mentioned, laid over a small torsion box. It is lightweight and has been incredibly stable over the years. Might be a good direction for you to go in.

[Paul Carson]

Thanks for all of the excellent feedback.

I've tried to source a two sided sheet big enough for my application here in Ireland but have only found narrow worktops to be available. One product made by I think 'Finsa' was listed 15mm total with thin MDF layer on top of chipboard followed by melamine - looked really good but nowhere here stocks sheets of it. Everywhere so far stocks the single sided sheets, which even with my very limited experience of chipboard I can't quite understand.

I've built a torsion box assembly table and this was my first thought for the board but didn't want to spend that kind of time building something when the commercial drafting boards are made from what looks like a 15mm melamine faced sheet.

Would glueing some 4mm birch ply to the back of a single sided sheet provide requisite support or create more problems?

Thanks

[Peter Kelly]

With a piece of 4mm birch plywood added to one side of the sheet it'd warp badly right off. Could lay up a piece of raw particleboard with high pressure laminate on both sides. Would be far stronger than just melamine-clad flakeboard.