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.

[John Lankers]

I built a drafting table like that for a friend not long ago. I used 2 layers of melamine faced particle board (2 sided) and some 2" wide melamine scraps to build the grid - basically a torsion box - and framed the whole box with hard maple, it is heavy but rock solid.
If I would have charged him for the labor he would have been better off buying one on ebay :rolleyes: .
Edit: I don't see why this approach wouldn't work with single sided, a single 4' x 8'sheet should be enough for the project.

[Jerry Miner]

If you can't find 2-sided stuff, why not get two pieces and laminate them back-to-back? Much more reliably stable that way, IMHO

[Wayne Lomman]

Jerry's idea sound like the best solution. I am somewhat thunderstruck that double sided is not available. Cheers

[Marty Schlosser]

John,

these "melamine" sheetgoods come in a variety of coating arrangements. Another one that's not often seen is hardwood veneer on one side and melamine on the other. Industry provides sheetgoods with only one side faced, for those unique situations when the craftsperson wants to place materials of their own onto the uncoated side.

Regarding your practise of applying veneers to melamine, I was wondering if you do so on both faces, or only one and leave the flip side with just melamine on it? I should mention here that I've scuff sanded melamine with P60 before using PVA to affix cherry veneer to both faces, and didn't run into any delamination problems. One was for a pair of bathroom vanity doors which are still standing up well after 5 years of daily use.


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.

[John Blazy]

Regarding your practise of applying veneers to melamine, I was wondering if you do so on both faces, or only one and leave the flip side with just melamine on it? I should mention here that I've scuff sanded melamine with P60 before using PVA to affix cherry veneer to both faces, and didn't run into any delamination problems. One was for a pair of bathroom vanity doors which are still standing up well after 5 years of daily use.

Good for you that you scuff sanded the melamine for PVA bond, but I challenge you or anyone to buy a tube PL Premium construction adhesive and do a side by side test of PVA (titebond or other) bonding wood or veneer to scuff sanded melamine, compared to PL (PUR) directly onto un-scuffed melamine, and you will totally see the difference when you try to delaminate or break the bond. The PVA will likely break at the adhesion interface, even though scuffed. The bond will be "good enough" for most purposes, but the PL bond will rip the melamine right off and take with it about 1/8" of the PB core - without any loss of adhesion at the PUR / melamine interface. I know it does not make sense, because I found out on accident, then did a series of break tests with samples placed in an arbor press with a scale to measure peak force held prior to break. ALL the PL butt joint tests exceeded ALL the PVA glue tests - whether dadoed, biscuited, doweled or screwed.

As far as balancing the panel by gluing to back face, there is no need when veneering with PL onto melamine, because of the two reasons you do so in veneering: Shrinkage of the face side when the glue sets, and to seal the back to prevent moisture absorption. The PL to melamine does not require that because the PL does not shrink hardly at all during cure, especially on a "Pre-sealed" surface like melamine, and the melamine back face is already sealed with the melamine face.

So anyway, after doing those break tests and discovered that PL is the strongest case fastening method possible, I no longer made my cabinet cases using biscuits, dowels, screws and especially not dado (which is stupid, because cutting the groove destroys the skins tensile strength, and no amount of adhesive in the joint will strengthen it again).

So the kitchen below, (and all others I have done when I ran a pro cabinet shop) has an almond melamine interior. All the boxes were fastened ONLY with PL premium PUR glue using butt joints only. During assembly, I shot finish nails in the front and back simply to keep the cabinet bottoms and stretchers in place to prevent drifting while the adhesive sets overnight. No clamps, because the PL expands as it cures - high bond whether clamped or not. I did clamp the double oven cabinet stretchers, bottom and tops, though, and used glue cleats below the oven shelves to add more insurance. Glueing in 1" x 3/4" melamine cleats under each shelf is still faster than dado, screws, biscuits, etc. and triples the glue surface area creating insane strength.

Here is the beauty of PL as the most under-used woodworking glue: it has the perfect sweet spot of viscosity - Just low enough to soak a little into porous PB core for a great bite, but high enough to not drip. This viscosity is also perfect for rolling onto a surface with a rubber brayer type roller when veneering. Since it is 100% solids, with no solvent, and cures via moisture, it does not skin over immediately, therefore allowing good penetration into wood. All the interior plywood woodwork (bulkheads, stretchers, etc) in my boat is glued with PL (the rest, epoxy).
345674345675

[Mel Fulks]

I recently helped a friend put up some paneling in a rental unit with PL Premium and was impressed with it. It's the only cartridge glue I've seen that does not stay gummy, it cures hard and tough.

[jack duren]

Good for you that you scuff sanded the melamine for PVA bond, but I challenge you or anyone to buy a tube PL Premium construction adhesive and do a side by side test of PVA (titebond or other) bonding wood or veneer to scuff sanded melamine, compared to PL (PUR) directly onto un-scuffed melamine, and you will totally see the difference when you try to delaminate or break the bond. The PVA will likely break at the adhesion interface, even though scuffed. The bond will be "good enough" for most purposes, but the PL bond will rip the melamine right off and take with it about 1/8" of the PB core - without any loss of adhesion at the PUR / melamine interface. I know it does not make sense, because I found out on accident, then did a series of break tests with samples placed in an arbor press with a scale to measure peak force held prior to break. ALL the PL butt joint tests exceeded ALL the PVA glue tests - whether dadoed, biscuited, doweled or screwed.

As far as balancing the panel by gluing to back face, there is no need when veneering with PL onto melamine, because of the two reasons you do so in veneering: Shrinkage of the face side when the glue sets, and to seal the back to prevent moisture absorption. The PL to melamine does not require that because the PL does not shrink hardly at all during cure, especially on a "Pre-sealed" surface like melamine, and the melamine back face is already sealed with the melamine face.

So anyway, after doing those break tests and discovered that PL is the strongest case fastening method possible, I no longer made my cabinet cases using biscuits, dowels, screws and especially not dado (which is stupid, because cutting the groove destroys the skins tensile strength, and no amount of adhesive in the joint will strengthen it again).

So the kitchen below, (and all others I have done when I ran a pro cabinet shop) has an almond melamine interior. All the boxes were fastened ONLY with PL premium PUR glue using butt joints only. During assembly, I shot finish nails in the front and back simply to keep the cabinet bottoms and stretchers in place to prevent drifting while the adhesive sets overnight. No clamps, because the PL expands as it cures - high bond whether clamped or not. I did clamp the double oven cabinet stretchers, bottom and tops, though, and used glue cleats below the oven shelves to add more insurance. Glueing in 1" x 3/4" melamine cleats under each shelf is still faster than dado, screws, biscuits, etc. and triples the glue surface area creating insane strength.

Here is the beauty of PL as the most under-used woodworking glue: it has the perfect sweet spot of viscosity - Just low enough to soak a little into porous PB core for a great bite, but high enough to not drip. This viscosity is also perfect for rolling onto a surface with a rubber brayer type roller when veneering. Since it is 100% solids, with no solvent, and cures via moisture, it does not skin over immediately, therefore allowing good penetration into wood. All the interior plywood woodwork (bulkheads, stretchers, etc) in my boat is glued with PL (the rest, epoxy).
345674345675

"Pro cabinet shop" Is this different from other cabinet shops?

[John Blazy]

Just referring to my for-profit business dedicated exclusively to cabinets, furniture and high-end millwork vs a contractor who does cabinets on the side, or those that do cabinetmaking for personal use (which I do now, cuz the business took the fun out of it). I should have stated "custom cabinet shop" as most cabinet shops just order box parts already CNC milled and they snap, glue and shoot them together like Conestoga, vs cabinets that are designed and built completely custom from sheet and solid stock.

[Paul Carson]

I was misinformed, there is two sided available from at least one supplier! I'll probably get 2x 8mm sheets and create a simple torsion box as suggested by Jerry to prevent sagging.

Thanks for all the advice. Paul

[jack duren]

Just referring to my for-profit business dedicated exclusively to cabinets, furniture and high-end millwork vs a contractor who does cabinets on the side, or those that do cabinetmaking for personal use (which I do now, cuz the business took the fun out of it). I should have stated "custom cabinet shop" as most cabinet shops just order box parts already CNC milled and they snap, glue and shoot them together like Conestoga, vs cabinets that are designed and built completely custom from sheet and solid stock.

There seems to be a lot of confusion at least to me as how cabinet shops call themselves. What is a cabinet shop and what are the differences? This should be a topic as it's confusing to me. 33 years in commercial,residential and furniture and still scratching my head at this.

[John Blazy]

There seems to be a lot of confusion at least to me as how cabinet shops call themselves. What is a cabinet shop and what are the differences? This should be a topic as it's confusing to me. 33 years in commercial,residential and furniture and still scratching my head at this.

Same difference between boat builders. Some build aluminum fishing boats for lowest price vs some building epoxy cold molded hull mahogany masterpieces (Van Dam boats). Both are boat builders. But which one do you think have dedicated themselves to the highest end craftsmanship and cutting edge technologies?

Maybe high-end millwork shop is a better description. But that could mean a guy that imports urethane foam molding profiles, and just cuts them to length for clients.

When I google "luxury private jet interiors" - then I see high-end "Pro" cabinet shops. That stuff is amazing.