Veneering Bulkhead in 4mm ply

[Pete735]

I've got 4mm cherry faced ply that I want to glue to an existing bulkhead. I've fitted plastic backed veneer before to renovate a boat interior and used both contact adhesive and pva, both held ok but have pros and cons. The contact needs to be positioned exactly, prior to fitting, the pva has the advantage it can be moved around but needs bracing whilst adhesive goes off. It's a big panel so fitting accurately first time will be tricky to say the least, even doing it in 2 halves.

Just wondered if anyone has used other alternatives that are maybe halfway houses?

Epoxy would be like pva and require bracing, wondered about polyester (car body filler) which sets reasonably quickly and is used extensively in modern boats.

I'd be interested in any helpful thoughts/ideas.

 

[prv]

Is there anywhere out of sight (perhaps behind a fitting like a lamp) that you could temporarily put a couple of screws through the ply into the bulkhead? That would provide your "bracing", and then you can use a slower-acting glue with plenty of time to position it properly.

Pete

 

[30boat]

Use a polyurethane or plysulphide building adhesive.No need to spread it over the entire contact area just put some blobs at regular intervals.Then offer the plywood up ,press and move as required to align.You'll have to come up with softwood wedges or a similar arrangement to keep it in place until the glue goes off.

 

[prv]

Use a polyurethane or plysulphide building adhesive. [...] You'll have to come up with softwood wedges or a similar arrangement to keep it in place until the glue goes off.

Good thought - and actually, some of those tubes have enough "grab" to hold up something light like 4mm ply without any bracing.

Pete

 

[capetown]

Cat bodyfiller

Car bodyfiller worked for me.

Put plenty on so squashes down so it finds it own level, a bit like brick laying I suppose.

Did mine a years ago, no helpful forum to ask in those days

Over GRP it has the advantage to level/true the panel over an uneven surface, also you have an open time to get the position correct.

We suported at the base and used 2x1 as props with plenty of duct tape.

 

[Tillernut]

THIXOFIX. It's like Evo Stik but you can position it before it sticks. It is also ideal for using in a confined space. You used to be able to get it easily in shops, however I needed to buy some last year and had to Google it.

 

[voicilesrosbifs]

Wet Grab

If the area to be veneered is large, I found Thixofix good, but difficult to spread fast enough before it started to go off. I ended up using some 'Wet Grab' adhesive (can't remember the brand). 2 seasons so far with no probs and easier to spread/work.

 

[TQA]

Use a polyurethane or plysulphide building adhesive.No need to spread it over the entire contact area just put some blobs at regular intervals.Then offer the plywood up ,press and move as required to align.You'll have to come up with softwood wedges or a similar arrangement to keep it in place until the glue goes off.

Not a good idea in a marine environmen IMHO. Just asking for an uneven surface if there is any differential expansion. As you would have to clamp you might as well apply whatever glue you decide on over the entire surface.

However do remember to prepare the plywood by removing any remaining release agent on the surface. Sand and wipe with acetone is what I do.

 

[Quandary]

Sikaflex (of 291 fame) do a variety of panel adhesives used for fixing shower panels, solar panels etc. I think the last one I used for this was 221, purchased in Jewsons?
Good grab so should not need clamping, but some scope for adjusting position. The stuff is reputable, moisture resistant and has enough flexibility to allow for a bit of differential movement. Your veneered ply is valuable, so worth spending £12 or so on a cartridge of proper waterproof panel adhesive, I do not think car body filler is the right stuff to use for this job.

 

[Pete735]

Thanks for the comments. I'm happy to spend a decent amount on a Sikaflex product or similar (not looked at website yet though) as once done I expect it to last for many years.

As PRV noted I may also be able to put a couple of screws through from behind as one idea was to use foam backed vinyl on a panel on the other side of where I am working. Only concern was not putting tip of screw through brand new veneer!!