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opinions & thoughts which may just be answers :)
By:Paul G. Jacobson
Date: 2/4/2003, 11:43 pm
In Response To: Questions.... (srchr)

: . . . If one glues veneer on a kayak with contact cement and covers
: it with epoxy/fiberglass you will have primarily only the strength and
: integrity of the contact cement bond in that area. In addition the contact
: cement will actually stop epoxy from penetrating any further. Contact
: cement is good...but not for strength. I'm thinking that it will be better
: to use one of the yellow glues, or epoxy, to apply the veneer.

Contact cement, or a chemically curing cement which uses some form of activating or catalyzing agent would be necessary when applying a laminate which was so dense that solvents or carrying agents in other types of glues could not evaporate through, or it could not absorb the glue, and so the glue would not harden.

If you are applying a plastic laminate like a Formica countertop you encounter this situation.

But with wood veneer you can certainly work with liquid glues. They get drawn into the pores in the wood, and the glue's solvents evaporate. About the only problem would be if the glue was heavily thinned with water and the moisture soaked into the veneer and caused that thin wood to expand considerably, perhaps changing its shape, or creating a bubble under the veneer.

The nice thing about contact cement is that you don't need to clamp the piece in place for any length of time while your glue dries. Same goes with glues activated by heat. You run an iron over the piece, and it cools in seconds with a very strong bond.

Now, will such bonds be strong enough for our use? Probably. While contact cement is not particularly strong, the bond covers a fairly large area. That area is then covered by the real structural element -- the resin encapsulated glass fibers.

We know from experience that a core of soft foam covered with a suitable glass and resin skin is strong enough for building kayaks. Obviously the strength of the core is not a major factor in this case. If so, then using a wood core which has an area of veneer on it is certainly not going to be weaker than foam, so it too should be "good enough".

If you built a hull from layers of veneer and ALL the layers were held together with rubber cement (a contact type glue which is about the weakest I can think of) it would probably be strong enough for typical use. About the worst that might happen would be if the hull deformed on a hot day if the glue softened and let the sheets of veneer slide around under the (also soft) glass and resin.

You would not see this with a veneer decoration bonded with contact cement onto a plywood boat, though. Since the fiberglass is well bonded to the wood, and it is not going anywhere, the veneer, which is also well bonded to the fiberglass, is going to stay in one place.

The heat activated adhesives are probably in the same family as those used for photographic drymount tissue, and I think you would have an easy time using dry mount tissue for holding on veneer, and the thinner the veneer the better, as drymount tissue needs heat, pressure, and it needs to be DRY. Moisture in the wood would cause a poor bond, but thin veneers would bake dry under the mounting iron. If you don't have dry mount tissues, try using a hot-glue stick. Use the hot-glue gun to apply a few small drops of glue over the back of your veneer, or place them over the area you wish to decorate. If the bumps are too tall, lay a sheet of aluminum foil (or a siliconized realease paper -- like the backing sheet on a roll of Contact shelf paper) over them and heat the area with an iron, flattening the bumps of glue. Keep the foil hot as you peel it off. When you are done you should have an even coat of your hotmelt glue. Now iron on the decoreative veneer and the glue will melt again, and bond as it cools.

Another thought would be to use the Heat N' Bond fusible webbing material used in holding the skins to the wood frames in ultralight S-O-F kayaks. It is very thin, heat activated, has a good track record with resistance to water and adherence to wood, and it is available in most fabric stores at a reasonable price.

Just some thoughts.

PGJ

Messages In This Thread

Material: Rehd: Gluing Veneer on S&G
grant -- 2/3/2003, 10:32 am
Well.....
srchr/gerald -- 2/5/2003, 7:25 pm
Gluing Veneer - another way
Jay Babina -- 2/5/2003, 12:58 pm
Response from Gougen Bros. :)
grant -- 2/5/2003, 3:54 pm
Re: Material: Rehd: Gluing Veneer on S&G
Rehd -- 2/3/2003, 11:43 pm
No Apologies Required
grant -- 2/4/2003, 9:48 am
Questions....
srchr -- 2/3/2003, 7:16 pm
opinions & thoughts which may just be answers :)
Paul G. Jacobson -- 2/4/2003, 11:43 pm
Heat n'Bond - Answering My Own Question *LINK*
grant -- 2/5/2003, 10:08 am
And Some Very Interesting Thoughts Indeed
grant -- 2/5/2003, 9:55 am
Questions.... on Veneer & Plywood Glues
grant -- 2/3/2003, 7:42 pm