O.K. you f/g experts, I need some help.

[Scott]

I wasn't going to get involved in this one with poly vs epoxy but
Honestly I would talk with a few more professionals, in the yards and suppliers, and get their advice first ... I dont think this is something anyone would want to do twice !!!

I've not heard about the glass spheres or microballons not being able to be used U/W ....Thats a common fairing material that can be mixed with other agents to make suitable fairing compounds... Cabosil is more "structural" and a bitch to fair. Again with talk of a barrier coat you are good to go.

Mat... I have always always been told that fiberglass mat, which is what I would use as the first layer against the damage area, Chemically and Physically bonds with the poly based resins. There is a chemical reaction between the mat and poly that creates chemical interlinking and bonding …. I think I would definitely want that in your situation. That first layer is going to hold everything together. The understanding I have is that this is not true with epoxy. Depending on how much you need to build up the suggestion is a layer of mat then structural glass( like the 1808) mat then glass. (You can also buy the glass with the mat already stitched in to the 1808 )

Look into Vinylesters ( higher grade polys and even Iso resin) as they are more water resistant ....plus if your doing a barrier coat your protecting it anyway. We all know that they are compatible with your hull...so there is no guessing

Joe Merton would be a good individual to call ... www.mertons.com he's great to deal with and in Springfield, Ma. and better yet is a SeaCraft admirer.

[Billybob]

Wow, thanks for all the advice, knew I could count on ya's.
What I think I know is that chopped mat is held together with some type of binder which reacts with the poly but is hard to wet out with epoxy.But they make a stitched mat just for epoxy that doesn't have the binder.
So, I was thinking of using that and cloth in layers.I am a little concerned about the whole mess sagging on me while I wait for it to set.I have used plastic sheet before as a release film so I'll have to figure out what I can do to support it.I guess I'll go with the thicker epoxy too, that should help some. Vacuum bagging is beyond me.
I also think you need apply your subsequent layers during the time between initial gel stage and full cure or you'll be sanding good between layers.
So, I'll keep you posted.
It's a really bizarre thing, I've never seen this happen to a boat before.

[warthog5]

(You can also buy the glass with the mat already stitched in to the 1808 )

18 stand's for 18oz per sqyd. The 08 stand's for 3/4oz per sqft.
A sqyd of 1808 weigh's 24 3/4oz.

That's what 1808 is. If you want Biaxle without mat a common number is 1700.

The use of extra mat with epoxy is a waste of good epoxy. the binder's don't relax right and it will eat up a ton of resign.
Mat is used to get good contact with the last layer laid. Like with the heavy Roven Woven's to fill the void's between the stranding.

1808 is available in +45/-45 and 0/90. This is the way the strands run. To maxumize strength you want to alternate the strand orentation.
You can cut the +45/-45 on a 45deg angle and lay it so it's 0/90. It's a little wastful with the material, but if the area is not so big and all you have is the +45/-45 it work's.

Mat is used for bulking the laminate up too. If you want to bulk it up, then why not add someting that has a whole bunch more strength. Like another layer of 1808. [img]/images/graemlins/wink.gif[/img]

[gw204]

So, if mat provides more harm/waste than good, what the benefit of using 1808 with epoxy as opposed to just going with a heavy cloth?

I though I almost had this glassing stuff figured out, until I heard the mat/epoxy incompatibility thing. [img]/images/graemlins/confused.gif[/img]

[warthog5]

Compatibility is a kind of wide open term. Epoxy will work with mat. It work's better with Polyester resign.

I think my point here is I don't like to see epoxy used with
1 1/2oz or heavier mat.

With the fact that epoxy doesn't break down the binders in mat, it makes it harder to conform to tight radius's

[Ed]

I agree with some of the above but definitely know that mat gets a bad rap.

Next time you are looking at some of the modern boats....ask to see a core sample. Not much mat, but a lot of spray core and core mat. Why? Resin is expensive and mat is very labor intensive. Spray core is cheap and easy to apply...and same goes for core mat.

Enough said unless we want to start debating over who makes the the best t-tops...New Englanders or Floridians?? [img]/images/graemlins/cool.gif[/img]

[FELLOW-SHIP]

A PICTURE IS WORTH A 1,000 WORDS.

http://www.legnosboat.com/lbiproducts/fiberglass.html

FELLOW-SHIP [img]/images/graemlins/cool.gif[/img]

[warthog5]

I hope your not buying from that place. Those prices are way high.
1808 Biaxial 50" 18 oz (0 degree x 90 degree) /.75 oz mat

1 Yd. Pkg. 1808-1 $14.70


Fgci is about $9.00per yd for the same thing. Their site is down again.

[FELLOW-SHIP]

Ha Warthog
No, I finished my boat I just felt like a few pictures might help.
FellowShip [img]/images/graemlins/cool.gif[/img]

[Billybob]

Thanks for the Mertons link Scott, that's close enough to drive to and actually feel the stuff.
I thought I'd put up a few pics even though it's still on the trailer.

Here's the view from the transom:


.
A side view:


.
Closer view:


.
Look at the delamination at the forward end! I know I'm gonna have to grind back til it's a good bond.It's quite a mess, huh?