Gents, I am only familiar with production of laminate countertops using spray-on contact adhesive, it suffices for 99.999% of what we build here when asked to make a countertop.

However, I have some upcoming work where the client is really wanting something they can trust won't delaminate from where their dishwasher is.

We typically edgeband our front edges using Dorus KS351 along with the required Dorus primer on the backside of the laminate, and then we spray-contact the top down. I'm reasonably confident in that but I have seen heat/steam debond both contact spray AND edgebander glue.

Labor costs aside, what should I be looking at? Should I just use something like West System epoxy and chuck this thing in the veneer press?

Normally I turn these sorts of jobs down because it's a check I may not be able to cash, but I have to admit that I have enough personal curiosity that I'm wanting to give this a swing. I occasionally build kitchen countertops for local churches and private schools who likewise need this sort of durability.

I would trust a type two pva such as Titebond II more than contact cement for steam and more importantly heat resistance. As for banding the edges, talk to your Dorus Rep to see if there is a better glue formulation for superior extreme condition adhesion.
Sometimes failure is in the substrate not the adhesive. What are you considering? Marine plywood or water resistant core is essential.

Exterior grade plywood and epoxy. A better substrate and a far better adhesive. Clamp in a vacuum bag.

It would seem the added cost in materials and time would bring you close to solid surface. Why not incorporate a bonded on PVC strip or small profile on the underside st the dw location to act as a bit of a deflector. Just a thought.

First years since our top fabricators have been laminating the bottom edge weve not had a failure

Thanks for the help everyone.

So Titebond II will bond well with the phenolic backing of laminate? Admittedly I've never tried it but have plenty of scraps laying around to try it on.

As for my substrate, I was planning on using either a good grade plywood like 3/4" baltic birch, or even OSB.

Mark B---- That's a good point about using a backer underneath. I get so used to doing "budget friendly, slam it out" type stuff with P-lam that I forget about this option. We have some leftover solid color P-lam laying around we can put on there before putting on the front band.

You are correct about the cost of solid surface ( or even granite, in my area they aren't all that different in cost). I'm going to leave that up to the client. I am not a solid surface fabricator so if they go that route, I can give them references. I've built only enough solid surface to know that I want someone else to do it lol.

Our fabricators have been laminating the bottom edges of the tops throughout for years. By default they just laminate the buildup but if you pay a little more they will laminate the 2 faces of the buildup (bottom and back face) and even toss a scrap of laminate on the underside of the top at the DW location. That way the entire DW area is in plastic.

The most moisture seems to come from low end dishwashers with a vent right under the top at the front edge of the door. If its really an issue I'd think a plastic profile that is fairly unobtrusive could be incorporated as a belt and suspenders but honestly since laminating the bottoms weve never had an issue. A low brow home center top, sure. They will be dead in a year.

Titebond II bonds well to plam. Hundreds of sheets no failures. Recent discussions with an elevator customer revealed that backer sheets don't give the same protection as regular plam. So now they back with reject sheets from the manufacturer.

I think your clients are barking up the wrong tree. There are millions of dishwashers with laminate counters over them installed with contact cement that didn't delaminate.

"As for my substrate, I was planning on using either a good grade plywood like 3/4" baltic birch, or even OSB." Either of those two materials would not be the best substrate choice because the they expand/contract with changes in humidity differently than the laminate you are installing on the surface. That difference will shear the glue joint. Particle board or MDF expand/contract at similar rates as does plastic laminate which is why they make a good substrate. Plastic laminate is made of paper (wood) which is why it changes with humidity.

If you want to put a backer sheet under the counter substrate where the dishwasher is, Okay, at least that is something simple. The most important part would to have the dishwasher properly installed. They should vent forward, there should be no leakage into the cavity. Proper glue coverage, drying time and pressure will go a long way in not allowing delimitation.

If you can get paid to re-invent the wheel without having to guarantee results, go for it. They (your clients) are going to spend a whole lot of money re-engineering something they know nothing about.

To clarify, I said OSB by mistake. I meant MDO. OSB would be a hideous choice, obviously. I cringed when I just now read what I had typed.

As Bruce says its over kill

I did 180 sheets of Marine Grade formica on half inch baltic birtch for a boat . With https://mcfaddens.com/p-137618-permagrip-pg107nf-spray-adhesive-non-flammable-35lb
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No problem the laminet is also fire rated
Particle board is garage this is probably what failed in the past for your customer.

Curios will the customer pay extra for all that extra work