Glueing onto laminate

[graduate_owner]

Hi all, I'm after advice again.
I need to fix some 4" wide tongue a groove boards to a melamine backing and was thinking of using glue to avoid nails showing. The t&g is very thin, only about 7mm thick, so I am not sure about skew nailing. Does anyone know of a glue that will stick reliably to the melamine? Would something like 'No more nails' work, or do I need a more specialised product?

K

 

[AndyT]

I'm pretty sure that sort of adhesive would stick the two together, but it might not solve the problem.

T&G boards will expand and contract in their width, as moisture content in the air changes with the seasons. Normally, they are either held in a groove or nailed. A groove will allow sideways movement. A single nail in each board restrains it at the nail but lets the rest of the width move. (Sometimes the nails will give a bit as well.)

The melamine (assuming it's on chipboard or MDF) would stay the same size regardless of the seasons.

If you succeed in glueing the whole width of your T&G to an immovable substrate, it may end up with splits in it when it shrinks.

If you can explain some more about what you need to make, someone may have a design idea which would work.

 

[AndyT]

After writing all that, it's struck me that you could use dabs of adhesive, or beads in line with the grain, which would fix the boards locally, like nails would. So as long as you don't spread the adhesive all over the boards, I think it would work.

 

[Eric The Viking]

I'd try double-sided carpet tape (Toolstation and elsewhere). It's slightly thicker than d/s Sellotape, and that gives it much better adhesion. If you only stick one edge it will allow your 7mm boards to move, which they probably will try to do. Obviously it's really a bit wide for your application, but with care you might be able to slit it lengthwise (depending on the lengths of your T+G).

The other stuff I've found to be good (so far) is the d/s tape used for sticking faux glazing bars to UPVC windows: I've been refurbishing the ones on the north side of our house this last year, as I've come to them whilst painting the house. Ours were wrongly installed about 15 years ago - there should be a 1-2mm expansion gap at the ends that meet the frames, without that the bars are forced off the glass they're stuck to. Several bars had come loose, and I removed and re-cut several others on the SCMS. I bought the proper tape to put them back, and it sticks lik a very sticky thing. It's not as strong as carpet tape, because there's a thin layer of foam in the middle, but it is really good. The foam would help you, as it will stick better to the uneven wood surface.

I'll dig out the supplier if you need it - they do a range of industrial tapes - but it is readily available on eBay and elsewhere. I needed an odd size, which was pricey, but the thinner widths are fairly cheap and would probably do your job well.

Clean both surfaces with a good degreaser - Acetone is excellent and pretty safe. Xylene is also good, but nasty. Meths is nothing like as good but does work. If using tape, leave the melamine smooth, if using glue, I'd roughen it with something like 80-120 grit as a mechanical key (then clean and degrease).

Hope that helps.

E.

 

[graduate_owner]

I hadn't thought of tape, and that might be just what I need for the job, which is fixing 3 ft lengths of t&g vertically to a melamine covered backing in a bathroom. The moisture issue hadn't occured to me (duhh) but I think you guys have provided the answer . Once again, thank you.

K

 

[Eric The Viking]

If you can, I'd store the boards in situ for a bit and see if they move - pick the ones that don't want to cup or wind too much.

If it does come loose, tape makes it fairly easy to redo it. I found Acetone was the best behaved solvent for the tape's sticky stuff, but it swelled up the foam layer. Not a big issue, unless you have foamed vinyl on the floor beneath, in which case be a bit careful.

 

[profchris]

I fear that your t&g will cup horribly in a bathroom, no matter how much varnish you apply. If you haven't bought it yet, see if you can get an offset and leave it in the bathroom for a couple of days to see what happens.

All the t&g I've seen is flat sawn, so I'd be very cautious. If it only cups a little you can decide if you'd be happy with the look. If it curls up like plane shavings, you won't have wasted all the effort.

I see that Eric the Viking says something similar, so that's two of us.

The end grain should tell you how bad the movement might be - that shallower the curve of the grain lines, the less cupping you should expect (though this isn't guaranteed, wood has a mind of its own).

 

[AndyT]

If you look at examples of T&G in use (ie matchboarding) you will see that normally the bottom edge is trapped behind a skirting board and the top end is behind a dado rail. Maybe you could do something similar, painted to match what else is around? It would improve your chances of keeping the boards a bit flat.

 

[tomatwark]

If you are going to paint it why not use neatmatch.

http://www.neatconcepts.com/neatmatch.htm

Most of the sheet material suppliers and some of the sheds sell it.

It is 9mm thick and then you can glue it on with no more nails.

 

[graduate_owner]

The t&g will be sitting on a shelf which is the top of a ' pipe boxing in ' arrangement, also made from chipboard / melamine and to be clad in t&g, this time running horizontally. My plan now is to stand the vertical boards on the shelf and glue the tops in place, either with a dab of adhesive or double sided tape, then fix the horizontal boards. This means the horizontal will butt up against the base of the verticals and hold them firmly against the melamine backing. The thin t&g I have won't give much of a hold, but I thought to buy some thicker board just for this section, or perhaps affix a length of suitable beading to increase the thickness where needed.
So hopefully the vertical boards will be held by the horizontals at the base and by glue at the top, with a dado rail to add extra hold at the top.

I think that will work. Once again, my thanks to all who offered advice.

K

 

[ED65]

Bit late but thought I'd mention that you can glue to melamine and similar using white PVA. All that's needed is to roughen the surface or score it deeply to provide a good key for the adhesive to grab to.