There's two different problems that might be present, pin holes vs.
cratering.

Pin holes in an epoxy coating are caused by air bubbling out of the wood.
As the epoxy cures, it gets warm, the air expands, and out it comes. The
trick is to prewarm the surface, either with the hot sun or with a hot air
gun. (I use a Black and Decker paint stripper type.) That way the surface
is cooling and the epoxy is drawn into the hole.

Cratering is tougher. It's a failure to bond. Surface tension pulls the
epoxy back away from the spot. I've seen suggestions that one should scrub
the epoxy into the surface with the heel of the roller or maybe "wet sand"
the liquid epoxy into the surface. (Messy!)

Roger

http://home.earthlink.net/~derbyrm

"1088" wrote in message
...
Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.

On Wed, 15 Jun 2005 06:51:14 +0000, 1088 wrote:

Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.
Things I've tried:
marine tex
west system epoxy and 407/404/talc
automotive bondo ($13 per gallon)
white yuppie-yacht bondo
system3 epoxy and 404
real smelly blue spot putty from the auto store
I was reasonably pleased until I sanded the second coat of primer
(parker 1040) vacuumed and washed and, and, and there they are again-
sons of bitches!
I'm definately open to suggestion at this point. Thanks for your time
as always.

You put bondo on a boat? I've heard that it has gypsum or something in it
and is a disaster on boats. I don't have any firsthand experience.
Hopefully it is not true and someone can confirm.

Roughly how many spots are there? And how wide are they?

What I'm getting at is would it be feasibly to treat them individually
with some kind of rotary tool?

--Mac

Personally, I'd use a pin vise and small drill bit. You're not excavating a
new missile silo.

Roger

http://home.earthlink.net/~derbyrm

"1088" wrote in message
...
On Thu, 16 Jun 2005 02:17:58 GMT, Mac wrote:

On Wed, 15 Jun 2005 06:51:14 +0000, 1088 wrote:

Roughly how many spots are there? And how wide are they?

roughly many. (50 - 100?) smaller than a pinhead. I widened some with
a chisel point; I think that worked better so far. I sand and vacuum
then I wipe with acetone. If it's damp out I attack with the heat gun.
After it dries I try and work the filler-du-jour in but it all pumps
back out like the hole is too narrow to let the air out through the
goop.

There's a scientific dictum about using the least injurious method . . .
first. Then following with progressively harsher techniques - IF the first
doesn't work.

What you describe is basically a *hydrolytic* problem. {Ironically, it would
'almost' be better if the holes went ALL THE WAY through}. You don't have a
'back-door vent', so you have to go to a 'strip mine' effect. What I would
suggest is the use of a straight wire brush . . . the HAND POWER kind. {Suck
up your guts, because this won't be pretty!!}. Take the brush, and with
MODERATE pressure, start scrubbing the area. Fore-and-aft, up & down,
circular fashion . . . your choice. What you are doing is opening up the
'pin holes' to small 'troughs'. Plus giving making 'tooth marks' for the
next step.

Brush the entire area, then vacuum, then wipe with denatured alcohol. At
this point there are a number of preparations {'Barrier Coats'} for the cure
of 'boat pox'. Each application lays down about a 5mil coat. A total of
15mils is the usual recommendation. Depending how paranoid you are, you can
follow this schedule - Lay down a couple of thin coats of epoxy, followed by
a fairing coat. Then after fairing, about 3 applications of a Barrier Coat.
Then two coats of your favorite anti-fouling paint. {Now what does that say
about ME !!}

You'll know before that first coat of epoxy goes beyond the 'green' stage
that the holes are plugged.

Regards and Good Luck,
Ron Magen
Backyard Boatshop
{This is what I DID after the 'Professionals' at the marina sandblasted
through the gelcoat and the first layer of 'glass. Their 'repair' had pin
holes all over . . . they got real ****ed when I made them do it over . . .
3 times !!}

"1088" wrote in message
...
On Thu, 16 Jun 2005 02:17:58 GMT, Mac wrote:

On Wed, 15 Jun 2005 06:51:14 +0000, 1088 wrote:

Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.
SNIP

Roughly how many spots are there? And how wide are they?

roughly many. (50 - 100?) smaller than a pinhead. I widened some with
a chisel point; I think that worked better so far. I sand and vacuum
then I wipe with acetone. If it's damp out I attack with the heat gun.
After it dries I try and work the filler-du-jour in but it all pumps
back out like the hole is too narrow to let the air out through the
goop.
SNIP

Still fixing my fixer-upper. I chiseled and sanded the crazing in the

I was reasonably pleased until I sanded the second coat of primer
(parker 1040) vacuumed and washed and, and, and there they are again-
sons of bitches!

Could be you just missed a bunch the first time. And you will miss more the
second time, and...
Been there. Done that

I'm definately open to suggestion at this point. Thanks for your time
as always.

On the other hand there's an overlapping discussion in an aeroplane
glider newsgroup that says any treatment over crazed gel that isn't
completely stripped to the mat is going to fail (re-craze) in 2-3
years.

That's what happened when I tried it. I wouldn't say that it "failed", but
the crazing was real obvious through the Awlgip...

A lot of work for a not so great result...

Geoff

On Wed, 15 Jun 2005 06:51:14 GMT, 1088 wrote:

Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.
Things I've tried:
marine tex
west system epoxy and 407/404/talc
automotive bondo ($13 per gallon)
white yuppie-yacht bondo
system3 epoxy and 404
real smelly blue spot putty from the auto store
I was reasonably pleased until I sanded the second coat of primer
(parker 1040) vacuumed and washed and, and, and there they are again-
sons of bitches!
I'm definately open to suggestion at this point. Thanks for your time
as always.

Maybe what you call "white yuppie-yacht bondo" should have been used
throughout. Automotive bondo _will_ absorb moisture. It may be
released when overcoated. Pinholes are the result.

I have no idea if this is what happened, but it certainly is likely.

Your "white yuppie-yacht bondo" costs about 8-9 bucks a quart. The
auto bondo cost maybe 5-6 a quart. Was it worth it to save three
dollars a quart? Didn't think so.

The most expensive ingridient in boatbuilding is labor. It's folly to
skimp on materials.

You need to use 3m spot puddy. It will fill the pinhole and be dry in 20
min. Then sand with 220 and paint.
http://products3.3m.com/catalog/us/e...er/output_html
--
Shield Finishes and Nauticoat Marine Finish Systems
www.shieldfinishes.com
"P.C. Ford" wrote in message
...
On Wed, 15 Jun 2005 06:51:14 GMT, 1088 wrote:

Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.
Things I've tried:
marine tex
west system epoxy and 407/404/talc
automotive bondo ($13 per gallon)
white yuppie-yacht bondo
system3 epoxy and 404
real smelly blue spot putty from the auto store
I was reasonably pleased until I sanded the second coat of primer
(parker 1040) vacuumed and washed and, and, and there they are again-
sons of bitches!
I'm definately open to suggestion at this point. Thanks for your time
as always.

Maybe what you call "white yuppie-yacht bondo" should have been used
throughout. Automotive bondo _will_ absorb moisture. It may be
released when overcoated. Pinholes are the result.

I have no idea if this is what happened, but it certainly is likely.

Your "white yuppie-yacht bondo" costs about 8-9 bucks a quart. The
auto bondo cost maybe 5-6 a quart. Was it worth it to save three
dollars a quart? Didn't think so.

The most expensive ingridient in boatbuilding is labor. It's folly to
skimp on materials.

On Sat, 18 Jun 2005 06:27:50 -0400, "Bruce on horizon"
wrote:

You need to use 3m spot puddy. It will fill the pinhole and be dry in 20
min. Then sand with 220 and paint.
http://products3.3m.com/catalog/us/e...er/output_html

If the pinholes are due to moisture entrapment as a result of using
cheapy materials, the pinholes will keep coming until all moisture has
been liberated.

On Sun, 19 Jun 2005 08:54:52 GMT, 1088 wrote:

On Fri, 17 Jun 2005 10:57:36 -0700, P.C. Ford
wrote:

On Wed, 15 Jun 2005 06:51:14 GMT, 1088 wrote:

Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.
Things I've tried:
marine tex
west system epoxy and 407/404/talc
automotive bondo ($13 per gallon)
white yuppie-yacht bondo
system3 epoxy and 404
real smelly blue spot putty from the auto store
I was reasonably pleased until I sanded the second coat of primer
(parker 1040) vacuumed and washed and, and, and there they are again-
sons of bitches!
I'm definately open to suggestion at this point. Thanks for your time
as always.

Maybe what you call "white yuppie-yacht bondo" should have been used
throughout. Automotive bondo _will_ absorb moisture. It may be
released when overcoated. Pinholes are the result.

I have no idea if this is what happened, but it certainly is likely.

Your "white yuppie-yacht bondo" costs about 8-9 bucks a quart. The
auto bondo cost maybe 5-6 a quart. Was it worth it to save three
dollars a quart? Didn't think so.

Brand name for this 8 - $9 product? Nationaly available? I paid $23
quart at WestMarine.

A quick look at fisheriessupply.com shows a marine polyesther at $11+
a quart. In gallon quantities it is $30 a gallon, or about $7.50 a
quart.

But let's say the only available product cost $23 a quart as you state
above. Was it worth it to save the $18 a quart. Didn't think so.
Statement below bears reading again.

Oh, and don't go to West. Highest prices, incompentent help.


The most expensive ingridient in boatbuilding is labor. It's folly to
skimp on materials.

Try a heat gun on the area wipe down with universal thinners before filling
with a smooth blend epoxy filler, ie micro balloons
"P.C. Ford" wrote in message
...
On Sun, 19 Jun 2005 08:54:52 GMT, 1088 wrote:

On Fri, 17 Jun 2005 10:57:36 -0700, P.C. Ford
wrote:

On Wed, 15 Jun 2005 06:51:14 GMT, 1088 wrote:

Still fixing my fixer-upper. I chiseled and sanded the crazing in the
gelcoat, then filled with several different things and the cracks are
covered ok but the tiny, tiny pin-holes will not fill. Many of these
looked like tiny black spots at first. Any attempt to fill them
results in some kind of gassing and the filler just ozzes back out
after a while.
Things I've tried:
marine tex
west system epoxy and 407/404/talc
automotive bondo ($13 per gallon)
white yuppie-yacht bondo
system3 epoxy and 404
real smelly blue spot putty from the auto store
I was reasonably pleased until I sanded the second coat of primer
(parker 1040) vacuumed and washed and, and, and there they are again-
sons of bitches!
I'm definately open to suggestion at this point. Thanks for your time
as always.

Maybe what you call "white yuppie-yacht bondo" should have been used
throughout. Automotive bondo _will_ absorb moisture. It may be
released when overcoated. Pinholes are the result.

I have no idea if this is what happened, but it certainly is likely.

Your "white yuppie-yacht bondo" costs about 8-9 bucks a quart. The
auto bondo cost maybe 5-6 a quart. Was it worth it to save three
dollars a quart? Didn't think so.

Brand name for this 8 - $9 product? Nationaly available? I paid $23
quart at WestMarine.

A quick look at fisheriessupply.com shows a marine polyesther at $11+
a quart. In gallon quantities it is $30 a gallon, or about $7.50 a
quart.

But let's say the only available product cost $23 a quart as you state
above. Was it worth it to save the $18 a quart. Didn't think so.
Statement below bears reading again.

Oh, and don't go to West. Highest prices, incompentent help.


The most expensive ingridient in boatbuilding is labor. It's folly to
skimp on materials.