Glueing wood veneer to plywood

[carioca1232001]

I need to restore the plywood/veneer at the port and stbd extremities of the maincabin/forecabin bulkhead.

Water had seeped through the foredeck/window column interface, a fault which was rectified recently, to include the dynelling and epoxying of the foredeck, coupled with new ipê windows and columns over the same.

The rotten plywood has been cut out of the bulkhead and a plywood patch installed in its place with epoxy glue.

The next step would be to seal the new plywood patch with epoxy resin. To seal the bulkhead plywood in its entirety would entail stripping it completely of all the wood veneer and then applying new veneer. :eek:

Which glue will give me the best bond between the new wood veneer and the repaired plywood patch ?
Bear in mind that the repaired plywood patch has been sealed with epoxy resin.

Thanks.

[Cullen T.M. McGough]

Gah. How's the bank account?

The purists would want you to:

1. rip out the bulkhead
2. strip/sand the bulkhead clean
3. vacuum bag the veneer onto the ply with epoxy or your favorite poisonous glue (the kids seems to like resorcinol these days, but I still say weldwood tastes better)
4. re-install the bulkhead

If you're cheap and/or caviler, you can try bonding veneer in place. The hard part is getting it to stick flat to a vertical surface.
You can try to cheat a bit and fabricate a plywood "double" of the surface you want to veneer, and then make a bulkhead|epoxy|veneer|double sandwich, and clamp it as tight as you can, and maybe throw a few screws through it too- if there are some nice spots that you can hide later under trim.

The danger is getting bubbles stuck in the middle. This is an all-or-nothing repair.

You could also consider contact cement, but i've never been desperate enough to try it.

Good luck!

[skuthorp]

Hmm! contact cement? I have a similar problem. Two L-shaped tears in the deck of a wooden Fireball that were roughly repaired years ago. The deck veneer is mirror-matched and I'm still carefully removing the old FG repairs as yet. Hopefully without doing any more damage.

[ 01-18-2006, 08:37 PM: Message edited by: skuthorp ]

[Todd Bradshaw]

I veneered the topsides and transom of a 22' Starboat using slightly thickened WEST epoxy and skinny-legged staples (Bostich T-11 Tackler gun) to hold it in place while the epoxy cured. The staple holes virtually disappeared with the final sanding, staining and coating and it turned out beautiful. I used 3/32" mahogany veneer (sawed and then thickness sanded, not peeled) which avoids the plywood look and was thick enough to be pretty much free of any tendency to curl. It's a fair amount of work and not cheap, but wouldn't be hard to do in place and is certainly quite sound. I'd epoxy coat the bulkhead and just paint it long before I'd try slapping veneer on with contact cement and I have a hard time believing that contact cement could ever be considered much more than a quick and dirty temporary repair.
http://www.imagestation.com/picture/sraid28/p44de098745dd08d99faeefeba740d688/fd682816.jpg

[ 01-18-2006, 11:44 PM: Message edited by: Todd Bradshaw ]

[Peter Malcolm Jardine]

Don't use contact cement. It won't stand up. Keep in mind that veneer will expand slightly with different glues... while you're trying to install it.

[Paul Girouard]

Does the new veneer have a phenolic backer ? Or is at raw wood veneer?

You can apply yellow carpenters glue to both the phenolic backer and the substrate , let both dry , as in just dry to the touch , not two or three days dry, then using a household iron apply heat and pressure , rubbing block to get a bond. The heat does the trick rub from one edge , out or from center both ways heat / rub etc . Iron set about 3/4 hot not as hot as it can be , keep it moving to not burn the veneer.

No idea if that will work over the "epoxy repair" , but on clean goods it does work.

Never tried it with raw veneer either.
Good luck , Paul

[carioca1232001]

Well, Brazilian carpenters use exactly what Paul Girouard suggests, namely, carpenters glue, a yellowish goo which gives off a heavy vapour. ( It´s sale is restricted, as young boys are known to get a kick while whiffing it )

The brand name here is CASCOLA and it seems to be identical to cobbler´s glue ( cola de sapateiro )though the latter goes under a different brand name.

Our wood veneer is of the raw type and some lumber supplies sell plywood-backed wood veneers but not phenol-backed. Plastic laminates, yes, (brand name FORMICA)are phenol-backed here. Our carpenters use the same yellow glue, CASCOLA, for the latter too when glueing it to plywood.

One exception - they do not resort to using a heated iron to provide the synergy between the veneer, glue and the plywood base, and I guess that this could be due to overall higher ambient temperatures in Brazil.

Our carpenters say that CASCOLA (carpenter´s glue) will not glue a raw wood veneer to an epoxy-resined plywood base . :rolleyes:

Our raw wood veneer is rather thin, no more than 15 mm thick, so am skeptical about glueing it on with epoxy-glue, as it is likely to crack after the glue sets. Right or wrong ?

Epoxy-glue will also make the thin, raw veneer less likely to absorb seasonal dimensional changes , as PMJ has pointed out above.

Should I sand off the epoxy from the already resined plywood and go back to using carpenter´s glue ?

What do I do ?

[Bruce Hooke]

I don't see why epoxy would CAUSE the veneer to crack. If you can get the veneer glued down without it cracking it seems to me you should be set. My big concern with epoxy and thin veneers would be the epoxy soaking through the veneer and messing up the finished face (assuming you are not planning to coat that with epoxy as well).

I agree that yellow glue will not stick well to epoxy (or hold up that well in a marine setting), and I certainly would not trust contact cement in an application like this.

By the way, I assume you mean 1.5 mm veneer (not 15mm), right? 1.5mm is actually reasonably thick veneer by my standards.

[JimConlin]

I've bonded veneers using epoxy and vacuum bagging and it worked very well. I was deliberately generous with the epoxy and it did flow through the veneer (1/16" Honduras mah.). A brisk sanding removed it and the veneer finished up nicely.

If Cascola has solvent that boys buzz on, it's probably a contact cement, not a yellow wood glue.

[carioca1232001]

You are right, the veneer is just 1,5 mm thick. Dropped a decimal point there !

The raw wood veneer will be finished with 2-part clear polyurethane, as is all the veneer within the cabin.

So if you feel the raw wood veneer will not crack after the epoxy-glue sets, I may just give it a try, because should some epoxy-glue seep through, it will not be incompatible with the 2-part polyurethane.

[Bruce Hooke]

I've not done a lot of it, but I have vacuum bagged some veneer with epoxy as the adhesive, and I've never had problems with the veneer cracking. As always with this sort of thing a small test on some scraps is rarely a waste of time!

[Trojan Dog]

I'm going to post an unpopular response here: There are contact cements, and then there are contact cements. The water soluble stuff is junk, it's just not sticky enough. Weldwood solvent based is ok for gluing down laminates, and works quite well (witness millions of counter tops in millions of homes). However, for your application I'd find some Pliobond, which is in my experience nearly waterproof. I've used it to glue canvas to wood and immerse it long term in water, and the stuff sticks like -- well -- glue... It will pull down a bubble in veneer and hold it there long term. The right contact cement will actually increase its tenacity with a little age. You can use Pliobond as one normally uses contact cement, or you can pre-coat both surfaces, allow to dry and then use the iron trick (see above). Part of this, of course, depends on how your veneer is cut, because that has to do with how much it will expand and contract vs. the epoxy/ply substrate. The rotary cut stuff with wild grain is the hardest to deal with. This will have to do with a little creep at the edges, though, not other sorts of failures. If you start with a clean, roughened and thoroughly cured epoxy/ply surface (acetone wipe), Pliobond will very likely do the trick, and I'd have more faith in it than yellow aliphatic resin glues. By the way, I don't work for Pliobond, and I'd not want to -- the fumes will fry your brain. Just Google "Pliobond" and you'll get more info than you want. Ace tends to carry it in small (pint) bottles.

[carioca1232001]

I Googled Pliobond and it looks promising, but is unavailable here. Shipping hazardous materials overseas has a prohibitive cost.

I may just try out the epoxy-glue route on a test piece

[Paul Girouard]

To clear up my statements , and I am/ was doing this P. Lam top tonight . http://i21.photobucket.com/albums/b299/PEG688/lam3.jpg
In the fore gnd. is P.lam "Wislon art" brand, and weldwood contact bond , not good glue at all , crap IMO . but I do little P.lam work right now so buying 5 Gal . bucket to have it go bad from sitting is not a option .

In the backgnd. is cherry wood veneer taped and wrapped around to show the Phinolic backer we have here in Washington state (sort of a brown paper) , and the type glue that would be used, a type #3 would also work , I think . and be a bit more water proof .

If I understand your situation your inside the cabin , so IF the hatch leaks again this repair will be wet , otherwise it is inside the boat , right?

P.lam glued and drying to be stuck soon , http://photobucket.com/albums/b299/PEG688/th_lam2.jpg

If your kids are wiffing it to get high, it's a contact bond. Got to go do it, work in progress . Paul

[ 01-19-2006, 10:43 PM: Message edited by: Paul Girouard ]

[Trojan Dog]

In my experience -- and with a fair amount of testing -- Titebond II and III are nowhere near being water resistant enough to use on anything that might be exposed to water infiltration over a long period (like a bulkhead might be given another leak). The stuff gives up pretty quickly. It also creeps a lot, particularly when subjected to heat. It's my last choice for veneers. Given what you have available, I'd use the epoxy.

[Jay Greer]

My own experience with a similar situation to what you are involved with involved gluing the laminates on with an epoxy paste cement called "Eppi Bond" . The laminate was applied to a tooth trowled epoxy surface and held in place with small brads driven through half inch square quarter inch plywood squares till it set up. The brads were then removed.
This was done on sheer strakes for a thirty foot sailboat. The job lasted until the planking was replaced some ten years later. We had to remove the overlay with chisels to get at the screws under it.
JG

[carioca1232001]

Paul Girouard wrote:


If I understand your situation your inside the cabin , so IF the hatch leaks again this repair will be wet , otherwise it is inside the boat , right?
Right !

Actually, the ply that rotted is at the port and stbd extremities of the bulkhead , as any water that seeps in on the foredeck , drops on the ceiling lining over the contigous V-berth ahead and trickles along the ceiling lining to the said spots.

You may be able to detect some change in the coloration of the veneer in the photos below, just by these spots:

http://carioca.zoto.com/img/45/167ef3f98055f5f5882683191ae04075-.jpg

http://carioca.zoto.com/img/45/5a70b4fec1149c9c9ee1df5b5163d82a-.jpg

As can also be noted, the stbd side (dinette) has another leak by the (slanted) column of the stbd. cabin window, but luckily the wood did not rot here. This leak is an off-shoot of the stuff at the bulkhead extremity.

As all the old white-wood strips were taken out on the foredeck, new slots cut out on the deck planks with a router and new white wood strips installed with epoxy-glue, plus an overall epoxy and dynel job over the works, the foredeck should be leak-free for some time at least. :rolleyes:

http://carioca.zoto.com/img/45/f0ef0f101180e5baf6d15bebbe09c115-.jpg