Grinding fibreglass to dry

[cutlass]

I'm about to leave my boat on the hard for the next 4 months in the Caribbean

There are some scratches in my gel coat that have let water into the fiberglass I think. Nothing serious but I want to grind it out and replace before I put it back in the water.

Should I grind out the wet stuff when I haul and leave it for 4 months to dry out?

Or should I wait til when i come back later in the year and grind it when I'm going to fix it?

Thanks!

[psneeld]

Originally Posted by cutlass

I'm about to leave my boat on the hard for the next 4 months in the Caribbean

There are some scratches in my gel coat that have let water into the fiberglass I think. Nothing serious but I want to grind it out and replace before I put it back in the water.

Should I grind out the wet stuff when I haul and leave it for 4 months to dry out?

Or should I wait til when i come back later in the year and grind it when I'm going to fix it?

Thanks!

Grind now...water will probably NOT dry out in a few months. I had pockets of water within a 1/4 inch of where I ground down for more than 5 months after I started grinding...I also found a 5 foot by 5 foot delaminated section requiring major repair down into 3 layers of roving/matt. Rain is actually good for the eposed areas as it washes off any chemicals that leaxh out of the wet fiberglass.

Grind now so you know what yo are dealing with.

PS..I hope you know that gel coats prior to vinylester really didn'y keep water out of the laminates underneath...that doesn't mean there IS a problem...just that gel coat water resistance is a myth.

[casual]

First how do u know water has entered the glass?Did you check with a moister meter?Last thing you want to do is grind away GOOD glass.

[psneeld]

Originally Posted by casual

First how do u know water has entered the glass?Did you check with a moister meter?Last thing you want to do is grind away GOOD glass.

It squirted out...and I could see it in the laminate in many areas.

Moisture meters are suspect in my mind (mainly because the user and their limitations)..

Another method (recommended also by West System Epoxies) is to tape clear plastic over the area...if water is in the laminates...it will appear on the plastic pretty quick if hot outside...but you have to have time to wait and wipe the plastic dry every so often till it stops accumulating moisture.

[DeepFrz]

Sounds like you might have a wet core?

[psneeld]

Originally Posted by DeepFrz

Sounds like you might have a wet core?

No not at all.....just wet laminates...why would you think I was so stupid as to not know the difference between a wet core and wet laminates??? I think I was pretty specific and not at all unsure of my diagnosis or recommended actions. There are lots of inexperienced in this forum...I'm not one of them.

Core???? I never even alluded to one...

[minaret]

Psneeld, chill. Pretty sure both casual and freeze were talking to the op not you.

[minaret]

We talking above the waterline or below? Above the waterline there is no way a scratch has let in enough moisture to be a problem. A crack, maybe. Below the waterline is a whole different story...

[psneeld]

Originally Posted by minaret

Psneeld, chill. Pretty sure both casual and freeze were talking to the op not you.

I don't think so...but you are right...you always post good stuff too...

[minaret]

Originally Posted by psneeld

I don't think so...but you are right...you always post good stuff too...

Thanks, we all try our best. Those guys should use the quote button for clarity, but unless otherwise specified I would assume all posts are responses to the op's question. Especially on page one of a thread.

[barnakiel]

Why all this drama about water and laminates (non-sandwich, just grp)?

Our hull was smashed against a steel larsen so that a chunk of about 1x1x2'' got 'removed'. We sailed like that for maybe a month, then fixed the boat drying her between tides. I inspected the place some two years later and did not find any osmosis / blisters nor any other signs asking for any further repair.

?

barnie

[psneeld]

Originally Posted by barnakiel

Why all this drama about water and laminates (non-sandwich, just grp)?

Our hull was smashed against a steel larsen so that a chunk of about 1x1x2'' got 'removed'. We sailed like that for maybe a month, then fixed the boat drying her between tides. I inspected the place some two years later and did not find any osmosis / blisters nor any other signs asking for any further repair.

?

barnie

Because it CAN be a problem...maybe not...but worth grinding down to see if the scratch is already there.

Some boats because of construction and location never have problems while others have severe...you don't really know till you investigate more than a glance at the gel coat.

[casual]

Originally Posted by psneeld

Because it CAN be a problem...maybe not...but worth grinding down to see if the scratch is already there.

Some boats because of construction and location never have problems while others have severe...you don't really know till you investigate more than a glance at the gel coat.

I,only replyed to the OP regreatfull you misinterputed

[barnakiel]

Originally Posted by psneeld

Because it CAN be a problem...maybe not...but worth grinding down to see if the scratch is already there.

Some boats because of construction and location never have problems while others have severe...you don't really know till you investigate more than a glance at the gel coat.

Why is this? My boat was built back in 1980 to specs made in 1967! She does not seem a rocket science (all lamination done by hand) and I bet materials back then were nothing fancy (today they ARE fancy = advanced - they have seen decades of improvement).

What are the (technology? materials?) differences that cause some designs to blister once scratched while allowing other designs to wear exposed grp meat for weeks without any apparent consequences?

b.

[psneeld]

Originally Posted by barnakiel

Why is this? My boat was built back in 1980 to specs made in 1967! She does not seem a rocket science (all lamination done by hand) and I bet materials back then were nothing fancy (today they ARE fancy = advanced - they have seen decades of improvement).

What are the (technology? materials?) differences that cause some designs to blister once scratched while allowing other designs to wear exposed grp meat for weeks without any apparent consequences?

b.

you are right it wasn't rocket science but there were MANY differences between even models from the same manufacturer in the same year....different resins, methods, application...etc..etc


there's ton's of info on hydrolysis/blisters internet scout it out...a lot of misinfo too so if you do have bottom problems you need to seek out the few who really have studied the subject (yard or individual).


if you don't have problems...you may not..but until you remove the gel coat or do some random coring...you never know how bad your boat may be hydrolysing.