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Re: Inexpensive glue instead of epoxy?

Posted: Thu Jan 01, 2009 10:35 am
by jem
tx river rat wrote:I didnt say nothing mister Matt
The art of speaking volumes without saying a word. :lol:

Re: Inexpensive glue instead of epoxy?

Posted: Thu Jan 01, 2009 3:18 pm
by hairymick
Need mo 'poxy,Need mo 'poxy,Need mo 'poxy,Need mo 'poxy, :P

Re: Inexpensive glue instead of epoxy?

Posted: Sun Jan 04, 2009 11:12 am
by Workin Man
Graham wrote:You know i always try to find a topic that causes some controversy. Has anyone had any experiences with polyurethane adhesives not as a replacement for epoxy just as a waterproof adhesive?.
oh and happy new year to all.
I have a small (8') home built jonboat that I used PL premium adhesive on. It is not a true stitch and glue boat though, it is built using chine logs. I applied a good bead of the adhesive to the logs before installing them. The transom was also installed with the same glue. I had to replace the transom this past summer (after 7 years including being stored outdoors in the winter), there was no sign of the adhesive failing. The entire boat is epoxy coated inside and out however, with 6oz glass on the outside of the hull, so there was no possibility of moisture getting to the glue. I'm not sure how it would have fared if it had been exposed to moisture, particularly over the winter. I did use epoxy to install the new transom though.

I'm sure most of you are wondering why the transom needed replacing on a 7yr old boat. The original was made of white pine biscuit jointed together, then epoxy sealed. The stress applied to it by the motor was causing it to crack along the grain of the wood. The new transom is marine ply instead.


Re: Inexpensive glue instead of epoxy?

Posted: Sun Jan 04, 2009 1:22 pm
by Kayak Jack
When I was a kid, during WWII, Dad made boats using marine plywood, framing, and Rogers' Fish Glue. Lots of brass screws too. He would then use Water Lox varnish to cover them. I don't remember any of them ever separating. No glass or epoxy.

They can be a lot lighter now with thinner wood, fiber glass, & epoxy.

Re: Inexpensive glue instead of epoxy?

Posted: Wed Dec 01, 2010 1:56 pm
by Oldtimer
Moisture curing polyurethane glue when used properly gives joints stronger than the wood or the glue that holds the plies of multiplex together.

1) It is NOT as strongly gapfilling like thickened epoxy.
2) It fills gaps with foam of no strenght.
3) So the joint has to fit perfectly.
4) Rub the glue on both surfaces of the joint.
5) Wait and see the glue penetrating the wood (darker coloring).
6) Wait further till the clear glue gets a somewhat milky appearence . (moisture out of the air and wood has started the foaming and hardening)
7) Clamp the surfaces tightly together.

So I made the scarfs for the gunwales of my canoe and fastened them in place