Laminate application on MDF

I am building a tabletop (small, 24 x 36) for use as an instrument stand at a trade show. I am using MDF as core material, and I will apply white Formica all over the built-up assy. It is (3) slabs of 3/4" MDF laminated together with screws and glue to make a top about 2.25" thick.

Any special considerations I should be aware of in applying the laminate? I am considering whether a high-solvent contact cement may be a better choice than low VOC or whatever else may be available. Any guidance is appreciated. I haven't worked with laminate in this application for a couple of decades...

MDF is a great substrate for that application. Only tricks/tips I'd suggest are the following:

-MDF doesn't like water. Expands and bulges and disintegrates. Not an issue for a trade show instrument stand (so a good choice for what you've got in mind). But not appropriate for say a kitchen counter.
-Once you apply the contact cement and let it tack, you only have one shot on alignment. So oversize the laminate and trim to fit after adhesion.
-Can be helpful to apply the cement to the MDF and the laminate then lay a series of wood stickers between the two. Once it tacks-up, you can remove the center sticker (letting the center of the laminate sag onto the MDF. Then progressively work outward, removing stickers and letting the laminate drop down to the MDF as you roll out any air pockets. Basically minimizes the potential for air bubbles. Not unique to MDF, just a good technique for laminating.
-You're creating a built-up core, so obviously take care squaring up the sandwich core before you begin laminating. You want the built-up edge to be well aligned and without voids for when you laminate the apron.
-MDF weighs a lot. Instead of a full three 3/4" slabs, perhaps you can just build-up the edge that receives the apron. Can save more than 1/2 the weight of your table...which you may appreciate when you're lugging it into and out of the show.

Commenting about the adhesive, i did a mental review of the last time i did a major formica job. It was the kitchen counters in our club hangar, so over 20 years ago already! I threw the remains of a dessicated 5 gallon pail out during the recent spring clean up. So realize i don't even know what is on the market. At that time i would have said avoid waterbase like the plague, especially with MDF. But maybe solvent base is no longer available or maybe the green stuff has gotten better?

I used to use 4' metal venetian blind slats (from a junk-shop commercial set)for the method D_d describes. As long as i was smart enough to take them out from the middle sequentially (those fumes, you know) they were close contact, low surface contact because of the C-shape cross section, and i didn't have to worry about a splinter sticking or snagging off under the laminate. I always cleaned them before use.

If this is a one shot deal (traveling to trade show) your stack of MDF method is fine. If you need stiffness than can't be accomplished only with 3/4" top and extended edges and plan to do this "routinely" I'd make the top honeycomb construction. Maybe 1/2" micrograin plywood on the working face, 3/4" edges, and 1/8" on the bottom with the honeycomb material in the middle. It could be laminated all over as you described. If you want to work harder, the top and bottom of the honeycomb could be laminated with the plywood faces & 3/4" thick plywood or softwood sub=edges retained between the top and bottom sheets. Then skinned with laminate, then 1/2" thick hardwood feature edging applied with epoxy, planed flush, and bullnosed.

smt

Couple more suggestions- If you are laminating solid sheets it's going to be heavy. You might consider one full top sheet and band the edges with 4" or so. Also, with MDF I have found that full depth pilot holes for the screws. Also, I think it is best to put a few coats of the contact cement on as the first coat soaks in quite a bit- especially on the edges.

I second the comment about full-depth (and width) pilot holes.

I've even had to go so far as to countersink the back-side of all pilot holes before screwing/gluing layers together because the material is so dense. The break-through from the pilot or the screw exiting the first layer has nowhere to go and won't compress. So joining two pieces without getting rid of whatever pushes through the first layer just ends up getting trapped between the layers keeping them from remaining in contact. So pilot full depth/width, countersink both sides of the pilot, then glue/screw together.

One other observation about MDF. It does not like screws into 'end grain' at all. Not an issue if you're just laminating two layers parallel to each other. But trying to screw them to each other perpendicular and you'll be fighting splitting and bulging from the one where your screw runs parallel with the face of the MDF.

Thanks to all for the info. What I read has more or less confirmed what I think I know about MDF and its potential headaches. The hint about separators for the gluing operation is darn fine, I hadn't yet really considered the handling step of two good-sized pieces covered in goo (or is that "glue"?).

I am certainly aware of the weight of the piece, after handling it through the tablesaw to true up the edges for glue prep after the slab laminating. And, having worked with MDF previously in a startup (late 80's) making speaker housings, I have had the experience of screws bottoming out, and no remedy except holes deep enough. I was careful of that during this assembly, so no worries there. I did indeed c'sink the bottom side holes for the clamping screws, but I didn't see any issues with chips/crumbs between slabs, maybe as they were clamped well together.

My biggest concern is making sure the laminate step doesn't screw the job up beyond redemption. I'm waiting on the Formica now, and need to buy the cement. Guess I'll see what is recommended by the "officials" as well. The possibility of a water-based adhesive causing swelling was a primary reason for broaching the question.

SMT, thanks for the design input. I absolutely don't plan to be making these routinely, but if it should happen, I'll give honeycomb serious thought. Maybe for the high-end gourmet interferometers, with some burled walnut edging and logo inlays. I did select the MDF for its vibration damping characteristics as an added bonus, though.

I like to do the edges first so that the top will overhang the edge so it is harder to snag the edge of the laminate when working on the top. Plus I think it looks better. You do want to make sure that your bearing on the trim bit doesn't score the laminate when you trim the last piece. Use a file to finish it up.

specfab said:

I am building a tabletop (small, 24 x 36) for use as an instrument stand at a trade show. I am using MDF as core material, and I will apply white Formica all over the built-up assy. It is (3) slabs of 3/4" MDF laminated together with screws and glue to make a top about 2.25" thick.

Any special considerations I should be aware of in applying the laminate? I am considering whether a high-solvent contact cement may be a better choice than low VOC or whatever else may be available. Any guidance is appreciated. I haven't worked with laminate in this application for a couple of decades...

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You in some sort of government funded therapy program, or what?

Sounds too much like work for a display unit just to avoid the spend of $24:

Commodity item, food & beverage trade. Just one example of dozens.

Reversible Table Tops – Rectangular & Square

Core between two or stack three and done. Go make something you CANNOT "just buy" so easily. MDF ain't worth any more effort than DIY paper towels.

if using the venetian blind slats, don't place them too far apart. They are low enough the laminate can sag between them. For some reason i thought your top was longer, like 5'. I reread, & for 2' x 3' I might just cut the laminated a good inch oversize all around and trust to luck. Or maybe not. I'm not as old a Bill, but my better, more graceful years may be fading. Plus just being out of practice.

Somewhere in there i missed what exactly screws were being used for? I really don't like screws under laminate. If unfilled, the laminate will begin to show them over wear areas. If filled and sanded, they can still push up which may be worse, and sometimes the body putty gets loose and causes a wider bubble.

Bill - if the guy is going to a trade show, the image he wants to project is paramount. You will remember from your daze in various fields the selling image is a large factor in the brand and price/value perception of the product. Those tops probably don't actually have laminate on them at the price, even as a commodity. More likely melamine printed on the wood with a rubber T molding popped in the edge. Used wrong, easy to connote "cheap"

That said, i sort of like the idea. I can see 2 of those with a perimeter of flat hardwood sandwiched in. Or even 1 x 1" aluminum. Hold the reveal where wanted, or extend past flush if preferred and/or go thicker. Add a few cross pieces internally. Attachment methods can include drilling all parts with shallow wide dimples to key with thickened epoxy, and clamping, to merely drilling and screwing up through the bottom sheet with counter sunk, obvious but unseen deck screws. Probably some other options besides.

smt

stephen thomas said:

Bill - if the guy is going to a trade show, the image he wants to project is paramount. You will remember from your daze in various fields the selling image is a large factor in the brand and price/value perception of the product. Those tops probably don't actually have laminate on them at the price, even as a commodity. More likely melamine printed on the wood with a rubber T molding popped in the edge. Used wrong, easy to connote "cheap"

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They are factory made to optimized processes by the millions of SQ FT all year long, world-wide use. We sit down at them all the time.

Better restaurants have bitchin' elegant surfaces, SubWay - still not bad. They are flat, rugged, not at all bad looking, and stand up well to chronic bumping and cleaning.

If I wanted an exotic laminate, I'd contact-cement it right over top of one of these so I didn't have to do what is already done - glue to the MDF nor worry about flatness. They come "reversible" as an excuse to put the melamine on BOTH sides for balance, do not warp easily.

Trade show? Yeah.. .done a few. Eventually had a staffer who managed ours for me - full-time job, year-round. Much of each year had to do with getting the specialists who build modular mobile displays to craft our latest one. Trade show displays that are practical for transport, set-up, tear-down IN that challenging environment are their rice-bowl. The best among them know things others do not, and are VERY good at what they do as to pragmatic displays that JFW, no matter how Buck-Rogers exotic they appear once set-up.

What is ON TOP OF that surface is what had best grab and hold the attention.
The deck under it should be unremarked. Job One for it is to NOT distract.

It should only be an eye-popper if you are selling... ability to provide custom laminates! ELSE.. "invisible".

Most places? It is done with locally rented foldables and textile draping anyway. Easier to not have to ship as much, nor have as much at risk of local damage.

Hope the OP is already aware of how restrictive these venues are as to whom is or is not allowed to deliver, unload delivery vehicles, move stuff once inside, load-out on departure, strict time limits, electric power.. yadda, yadda, 'coz if not, it can be a sore frustrating education.

I'd probably be putting far more ingenuity and craftsmanship into a bespoke protective shipping container that could double as a brochure store or a riser once the "gadget" it had protected was out and on display. You daren't risk it going walkabout whilst in a secondary storage area. BTDTGTTS on that as well.

Without that protection, all too easy to have a borderline disaster.

I had built some meself, had my first one built by a pro, 1970 IEEE Eastcon instead, outdrew IBM - one position over - in attendance [1], damaged nothing, never looked back at DIY.

Too much at stake. "Find the Experts!"

[1] Well we DID have the world's first-ever real-time digitized color graphics display of satellite information. OSO-G - a UV spectrophotometer mapping sunspot activity, NASA Greenbelt our client, with digitally-assigned human-visible color code conversion from the UV intensity.

More of an eye-catcher than IBM's 80 thousand character per second CRT-type ink-particle printer the eye couldn't keep up with. All IBM had for a "draw" was a bigger booth and the odd noise as a few feet tall stack of paper vanished from one pile and ended up on the other!

As far as screws are concerned, drill out and install cemented plugs for the screws. Particularly for the "end grain"

Tom

Thanks again to all with contributions to the question at hand. For those concerned, my colleagues and I have a fair amount of trade show experience under our belts in our previous successful ventures, so this isn't a wet-behind-the-ears scenario. In a self-funded startup, ya do what needs to be done to save handing the money out to the less-deserving. When the product(s) become self-sustaining, then you have more flexibility in spending. In-house capability is a wonderful thing. You have many more choices.

The screws of which I spoke earlier are indeed just for clamping the laminations together, and were installed from the bottom side to allow for a "perfect" top surface to glue the laminate to.

specfab said:

Thanks again to all with contributions to the question at hand. For those concerned, my colleagues and I have a fair amount of trade show experience under our belts in our previous successful ventures, so this isn't a wet-behind-the-ears scenario. In a self-funded startup, ya do what needs to be done to save handing the money out to the less-deserving. When the product(s) become self-sustaining, then you have more flexibility in spending. In-house capability is a wonderful thing. You have many more choices.

The screws of which I spoke earlier are indeed just for clamping the laminations together, and were installed from the bottom side to allow for a "perfect" top surface to glue the laminate to.

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I suspect you have the savvy to have used the vanilla MDF & laminate as an excuse!

NOW you have the whole PM community salivating for sight of just what sort of clever gadgetry is going to be set ONTO it!

Pictures.. or we'll hold yer contact-cement for ransom!

For anyone interested, fresh out of the box at SPIE trade show in San Diego, sitting on the Formica tabletop in question:

I hope you got the table flat given the product sitting on it.

InterOptics

We pay attention to flatness in ALL situations. ;-)