Poor fibreglass adhesion to plywood

[kell 9]

I am building my transom and I got 2 peace’s of 3/4 marine grade plywood I am using fibertec polyester laminating resin and 1708 I can’t seem to get a really good bond I am pre soaking it it’s clean ect and I can usually pry it up and peel it off . Is this something to do with marine plywood ? It’s like it’s not absorbing the resin well it wants to sit on top when pre soaking almost right away it seems

 

[Scott Danforth]

Marine plywood and not treated, correct?

How old is the resin?

 

[kcassells]

Meaning did you wet it out and let it dry then lay glass?
Or
neighbors cat pissed on it

 

[kell 9]

Marine plywood and not treated, correct?

How old is the resin?

Marine not treated and not even a year old

 

[kell 9]

Meaning did you wet it out and let it dry then lay glass?
Or
neighbors cat pissed on it

I thought I pre soaked it well
Enough maybe I need leave it on there thicker ?

 

[kcassells]

I thought I pre soaked it well
Enough maybe I need leave it on there thicker ?

you need to wet it out prior to glassing. Soaks into the wood. Let it dry.
Come back wet out again and lay glass.
If not wet out the 1st time to dry then wood and glass soaks up resin but creates a horrible bond.

 

[kcassells]

post pics

 

[stresspoint]

this is the reason i use structural ply,
marine ply takes too much work to get the resins to adhere properly .

OP , you need to sand with 36 - 40 orbital sanding disc prior to laying up , "" do not wipe with acetone or thinner prior to lay up "" , dust down with ""dry"" compressed air then lay up..

 

[Chris1956]

Gee, mix in a bit less hardener and let the resin soak into the plywood for longer. I replaced my transom on a nice warm day and mixed maybe 3/4 of the hardener usually called for. It took hours to harden, but it soaked into the plywood very well.