Epoxy Resin/Fiberglass Tape: Milky Areas?

(PeteCresswell) wrote:

> Water weeping from the seam?

That's possible, as it would turn uncured epoxy milky.

> Contaminated tape?

Possible, but unlikely unless it was laying around or you cut it on an
unclean surface.

> Something else?

Air bubbles. Squeegeeing too hard can drive micro-fine air bubbles into
the resin. Your technique will dictate whether that's even a possible
cause.
 >> Stay informed about: Epoxy Resin/Fiberglass Tape: Milky Areas? 

Pete,
Sounds like an 'epoxy starved' area, to me. Either not enough epoxy
UNIFORMLY applied to begin with, or an area rolled/squeegeed to hard and the
epoxy pushed away. To avoid this I usually apply in 2 to 3 'steps . . .
a} with raw wood - I put on a coat of unthickened epoxy and let it cure . .
.. then cut parts. b}With repairs or applying cloth to a hull . . . apply a
coat of unthickened epoxy and allow it to 'set' - from just when it looses
it's tackiness, to the 'green' stage.
c}Lay out the cloth/tape . . holding it in place with 'thumb pins' or
masking tape, and apply epoxy mixed with a bit of fumed silica as a
thixotopic agent - more then a little if it will be painted or I don't need
a Clear finish.

Regards,
Ron Magen
Backyard Boatshop

"(PeteCresswell)" <x.RemoveThis@y.Invalid> wrote in message
news:arie62dfrg89bb0mu6gomavc83rm1ckotg@4ax.com...
> Just finished applying about 40 feet of 1" fiberglass tape to a surf ski's
> (long, skinny sit-on-top kayak...) hull/deck seam using West System epoxy
resin.
>
> 99" of it went as expected, but I've got a few areas (2" max) where the
> resin/tape is milky white. In the longest area, it was uniform from one
edge
> of the tape to the other. In the smaller areas it doesn't extend the
full
> width of the tape.
>
> I guess I'm going to grind it off once it's cured and try another layer,
> but the suspected cause will determine how I go about applying subsequent
> layers.
>
> Water weeping from the seam? Contaminated tape?
>
> Something else?
> --
> PeteCresswell
 >> Stay informed about: Epoxy Resin/Fiberglass Tape: Milky Areas? 

Per Ron Magen:
>Sounds like an 'epoxy starved' area, to me. Either not enough epoxy
>UNIFORMLY applied to begin with, or an area rolled/squeegeed to hard and the
>epoxy pushed away. To avoid this I usually apply in 2 to 3 'steps . . .
>a} with raw wood - I put on a coat of unthickened epoxy and let it cure . .
>. then cut parts. b}With repairs or applying cloth to a hull . . . apply a
>coat of unthickened epoxy and allow it to 'set' - from just when it looses
>it's tackiness, to the 'green' stage.

I guess I could try the following - but it would take a day or two with 12-hour
cure times.....

Can I paint the surface with a thin coat of epoxy, smooth on the cloth, let it
cure, and then squeegee more epoxy over top to completely saturate the cloth?
This would be a nice solution to some situations where the edges of the cloth
want to curl up because of curves in the surface - tack one side down, tack the
other side down, then saturate.
--
PeteCresswell
 >> Stay informed about: Epoxy Resin/Fiberglass Tape: Milky Areas? 

Pete . . .
'read' between the line . . .

"(PeteCresswell)" <x.TakeThisOut@y.Invalid> wrote in message
news:esgf62p4up4hcmlg19a7r2meekdme9suf8@4ax.com...
> Per Ron Magen:
> >Sounds like an 'epoxy starved' area, to me.
SNIP
>
> I guess I could try the following - but it would take a day or two with
12-hour
> cure times.....
Not really -
>
> Can I paint the surface with a thin coat of epoxy, smooth on the cloth,
let it
> cure, . . .
NO - Neine - Nict . . . Do NOT let it cure before adding the 'fill coat'
or you will have the SAME problem {Did I mention you are going to HAVE
to cut out and feather the 'starved' parts}

and then squeegee more epoxy over top to completely saturate the cloth?
> This would be a nice solution to some situations where the edges of the
cloth
> want to curl up because of curves in the surface - tack one side down,
tack the
> other side down, then saturate.

Try . . . 'paint' ENTIRE surface with unthickened epoxy{then let set, or
'heat accelerate' till tackiness gone, or immediately proceed on 'wet'
epoxy - your choice}, then UNROLL the glass tape into the epoxy. Use a stiff
disposable 'chip' brush to DAB it into the epoxy and use pins where it
starts to slip - pinning it in place as you go. Mix up another batch of
epoxy - unthickened, or slightly thickened - and dab it or GENTLY brush it
on to saturate the cloth WITHOUT getting runs, 'curtaining', or sags in the
cloth.

Either way, a few hours should do it - unless your ambient is around 40
degrees F.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

> --
> PeteCresswell
 >> Stay informed about: Epoxy Resin/Fiberglass Tape: Milky Areas? 

@#@

Milky white indicates an area that has contamination mild acids etc will do
this. Just cut the piece out clean with acetone and redo, no big deal.

Ray
"(PeteCresswell)" <x.DeleteThis@y.Invalid> wrote in message
news:arie62dfrg89bb0mu6gomavc83rm1ckotg@4ax.com...
> Just finished applying about 40 feet of 1" fiberglass tape to a surf ski's
> (long, skinny sit-on-top kayak...) hull/deck seam using West System epoxy
> resin.
>
> 99" of it went as expected, but I've got a few areas (2" max) where the
> resin/tape is milky white. In the longest area, it was uniform from one
> edge
> of the tape to the other. In the smaller areas it doesn't extend the
> full
> width of the tape.
>
> I guess I'm going to grind it off once it's cured and try another layer,
> but the suspected cause will determine how I go about applying subsequent
> layers.
>
> Water weeping from the seam? Contaminated tape?
>
> Something else?
> --
> PeteCresswell
 >> Stay informed about: Epoxy Resin/Fiberglass Tape: Milky Areas?