plywood glue question..

[kng]

Hi people !! as you know i´m building the Grey Seal, and as you know too, it has lots of joints bonded with epoxy, i would like to ask you how much we can or must trust not the epoxy but the glue of the plys in the plywood?? i have detected the first ply of one of my plywood sheet that it is unbonded in some parts... my question is if we could make (a long the planks lands i.e.) holes about two or three ply depth and for example 5" between one of each other, and hoping that this could add strength to the joint...
thank you very much !!
cheers !!

Emiliano.

[Pelle]

Hi KNG!

I did not understand what you ment making holes ....
Fill them with epoxy or something ?? All I can say is that when the plywood looks suspect (delaminating, "glue starvation") you can bet the
plywood is much worse than you think. Has it been
exposed to water ?? You might be in for a surprise. Water will make the wood swell where the
plywood is not properly bonded.
As we have discussed here at the forum; There's a lot of nasty plywood out there. Be careful!!
Look at my site http://home.world-online.no/~dreggen what can happen when you use plywood not up to the job !

Pelle

[NormMessinger]

What kind of plywood are you using, Emiliano? Surely not Lloyds BS-1088?

--Norm

[kng]

Hi !! i really noticed this problem only in one sheet and more detail in one plank i cutted when i was cutting the plank from the pattern the circular saw delaminate in some parts the first ply, that really sacared me !! what i was thinking was to make many holes a long the joint to increase the bonding surface and to bond the plys under the surface... i don´t know if this will make a diference...
the plywood was made here in Argentina, i know it is the best i could find.. because there is no more good quality plywood here, but i know that it has some age because they were the last of the shop... all the plys are made of Cedar the inner and external too. I think it is of good quality... I am scared for what i would see in your page !! but i will....
i also get the bad bonded areas out and i will fill that with epoxy..

thanks !!
Emiliano.

[Pelle]

Hi!
I doubt that you can fully saturate unbonded, hidden plies by injecting epoxy through some holes on the sheet. My experience is that it is impossible to spot unbonded areas by just looking at the sheets surface. As stated, the tragedy will reveal itself only after exposure to water. Even if the sheet is to be covered with epoxy, someday water will get past and... you know....
If it's to be used for a boat, please try to get something with a proper glueline between the layers.

Pelle