What adhesive - that shrinks when it sets - do you recommend for melamine laminate sheets?

Hi

What adhesive that shrinks as it sets would you recommend to bond two large sheets of melamine covered boards (AKA laminate) together?

Background
Some adhesives (e.g. Gorilla Glue?) are designed to shrink significantly when they set. In some situations, this can help create a really tight bond. However anything that uses a 'moisture cure' may not work so well between a moisture barrier plastic such as Melamine. My sheets will be at least 1m x 1m.

Thanks

Don

All PVC glues ( most of the white wood glues) shrink when curing, but all tend to cure by water evaporation - Gorrilla glue does not shrink - it expands, as do most polyurethane glues. However these glues cure process is triggered by moisture - very little moisture is needed and is 'consumed' in the process - there is no residual moisture left in the bond, so you would not have a problem with trapped moisture . However.... It can expand 2 to 4 times the applied thickness, bonding impervious surfaces, but pushing them apart...

Perhaps a slow cure epoxy and clamping the boards together, or laying them flat and weighting them?

What is the application?

Why don’t you contact some adhesive manufacturers and ask them the question, after all they make the stuff and are the most qualified people to answer your question, that’s why they all have technical departments.

The factory used to use a contact adhesive similar to evostik, wouldn't want to work in that factory!!!

I expect they use less-nasty contact adhesives these days. I’ve always used a contact adhesive for glueing melamine to a timber substrate, but gluing melamine to melamine might be another matter.

Personally I see no particular reason to stick boards together. Better to buy the correct thickness board in the first place?

Styccobond F56 is used by a local flooring company but might only come in the 15litre tubs in their skip. Judging by the smell it is a friend of evostick.

off-topic but the bits of vinyl or whatever they also have in the skip are about 3mm thick and would be a great benchtop covering. It is thick enough for other modelling uses if only they would throw away big bits but is embossed on the top surface with a wood grain.

What is the actual product you are gluing as melamine is not a laminate that is often bonded in the home workshop as it is only paper thick (approx 0.1mm) and easily damaged. More likely you have some form of melamine faced board such as MFC or MFMDF. I suspect the posts here about evostick are more related to HPL (high pressure laminates) typically Formica than LPL (Low Pressure laminates) which melamine falls into.

Not stuck it to itself but Titebond melamine glue is OK to stick it to porus surfaces such as ply and MDF, Axminster do small bottles of it.

Edited By JasonB on 30/03/2022 18:31:25

VHB tape may be the answer!

Many years ago built my own kitchen cupboards, chipboard doors covered with Formica fixed with Evostick contact adhesive. Never came off while I lived with it, moved after ten years.

Although I preferred contact adhesive for single sheets. If I had a lot I often would glue down sheets of formica with PVA adhesive & put them in the door press. I used to buy a PVA from a local chemical company, formulated for the job. But then I would buy in quantities up to 1 tonne at a time, as it could be used for exterior joinery as well.

To speed things up I sometimes added a little water & used a radio frequency gluer to set the adhesive.

Ordinary PVA will do the job, provided it can be clamped & left

Edited By Sam Longley 1 on 30/03/2022 22:20:01

The traditional glue for sticking melamine to bench tops was contact cement by applying a coating to both surfaces and allowing it to dry until it was no longer sticky to touch. The glue is intended to stick and hold on contact and there should be no slip between the 2 surfaces.

Then position some spacers (lengths of dowel rod or similar) on top of the bench and lay the melamine sheet on top of the dowels. This allowed you to align the melamine with the bench without touching it. Then, starting at one end, remove one of the spacers and press the melamine firmly to the bench to remove any pockets of air. Then remove the next spacer and do the same until all spacers have been removed.

Ask your local hardware store, cabinet maker, kitchen remodeller, handyman etc so you can enter into a two-way verbal conversation. Trying to negotiate your inevitably hyper-specialised needs via the limited discourse of a forum has proven before to waste a lot of members' time on rejected or irrelevant solutions. All it does is generate dozens and hundreds of unnecessary clicks on the site.

Yes I am bonding 2 large 100cm x 100cm sheets of Melamine Faced MDF. I am wanting to create a rigid work surface that is as flat as possible. Most of the time it will be used on a table but under a cutting mats.


In terms of what I already have:

A) PVC wood glues - It sounds like they would shrink but they would take "forever" to cure by evaporation through the Melamine.

B) Original Gorilla Glue - is a water activated polyurethane that expands (a lot) before it sets. If any additional moisture is required to diffuse into the glue (beyond what is already on the surface), that might take a long time too.

C) Collall All-Purpose Glue - is solvent based (acetone+ethanol) I think, so again the solvent would presumably struggle to escape.

D) Sealants & rubber glues (various - e.g. CT1, Dowsil 732, Sikaflex EBT+, Sikaflex 508., Shoe Goo, Shoe Goo2 etc) - but I think they are either cured by moisture going in or solvent coming out. Melamine might interfere with either process.

E) Various Super-Glues - (which I find hard to use reliably)

F) Epoxy Resins (e.g. BSI [Bob Smith Industries] 5 min Quick Cure, Zap Z-Poxy 30 mins, J-B Weld original "Cold-Weld"...)

G) Contact Adhesive - I do have some "All-Purpose Professional Welder Adhesive". Would that do?

Titebond Melamine Glue sounds promising - however would need to buy it.

So it sound like a toss-up between with my "All-Purpose Professional Welder Adhesive" or an Epoxy Resin?

Any further recommendations?

J

For a 100cm x 100cm area, you will need a lot more than the 2 tubes of contact adhesive shown. Use a paint scraper or spatula to get it on fast to get an even coating before it starts to set.

Pay the money for the Titebond Melamine Glue whose name says it all.

NO NO NO

If that is what you are doing then DO NOT use the titebond as it is designed for one surface to be porus as I said. There will be nowhere for the water content to go.

A contact adhesive spread with a fine notched spreader would be the best option but make sure you get it on evenly as I doubt you have anything to press the sheets together with as any blobs will increase the gap locally and not give you a flat surface. Buy a 500ml can not hobby tubes, something like Evostik 528 or Evostik "Impact" are easy to get hold of

I doubt you are using MRMDF core so make sure the edges are sealed well otherwise the plain MDF core can swell with moisture or even shrink in very warm homes

Only advantage for you of using an epoxy is it is more repositionable than contact adhesive so better chance of getting the edges of the two boards lined up. Your bottles of ZAP would do it.

Edited By JasonB on 31/03/2022 08:47:39

So why not make life easy and use a piece of readily purchased MDF board with Melamine already glued on both sides in the factory? Seems like a lot of faff to make a flat surface to lay on top of a bench under a cutting mat the way you are proposing. There must be (are) easier ways to provide a flat surface.

Personally I would go for a sheet of plywood. Less likely to slip around on the bench top and less likely the mat will slip around on top of it at the same time. Double sided Melamine is slippery city.

Or if the capital investment of a piece of plywood or MDF with Melamine both sides is prohibitive, what you are looking for is something to glue MDF to MDF, not melamine. Pretty much any glue will do that.

Edited By Hopper on 31/03/2022 09:28:08

Personally I would start by sanding the two surfaces with something like 120grit paper to give something for the glue to grab onto.

Contact adhesive would be my go to. If the boards sag a little some battons layed across the bottom sheet on the glue do not worry about it sticking as it relies on both surfaces to have glue applied, this will allow you to line up the two boards then remove the sticks one by one and allow the boards to come together once they come into contact it is stuck.

You will need to apply pressure to the boards to really get a good bond so lay it onto something flat and then cover with plastic and place heavy blocks on it as I doubt that you would have something like a vac system, the other method is to have thick battons top and bottom and clamp these the best you can.

How thick are the 1000mm square panels? Are they Melamine faced or SRBP -Formica faced. If the former, delaminate the faces to be bonded together and use a wood glue.

Regards Ian.

Why do I keep thinking the OP is going to use two pieces of ~15mm melamine board stuck together rather than a single chunk of decent kitchen worktop?

I really think the OP is complicating something rather than applying the KISS principle - and will continue to do so, unless we are provided with complete dimensions (ie thickness).