An idea:
I haven't done this so YMMV.

If you're trying to reconstruct a failed deck core, and the boat can be
turned upside down, then you can cut out the inner skin and the pulpy core
and construct a new core and inner skin working DOWN. If that's not
practical, how about laying the boat over on its side? Wallpaper is not an
impossible PITA.

Working overhead, I've had a lot of trouble in relying on stickyness of
resin.
If you really have to work overhead, I'd try very hard to devise a vacuum
bagging method. The conventional arrangement of laminate|peel
ply|bleeder-breather|bag depends on gravity to keep the resin and air where
they should be, if there's a choice. Invert it and you'll end up with airy
laminate and saturated bleeder-breather. NG! Maybe substitute a thin
transfer medium for the b-b or leave it out and suck from the top side
through perforations? THis could get complicated.

Of course, the practical solution is to cut out the top skin, re-laminate
working down, as the god of gravity intended, and finish with a gritty paint.

Thanks guys, I was asking for a friend. I haven't seen the project
yet. Would there be any advantage to thickening the resin?

Steve wrote:
"rhys" wrote in message
...

On 17 Mar 2004 09:29:27 -0800, (jsheesley) wrote:


Do you guys have any advice, tips or tricks for laying up fiberglass

overhead?

Besides "avoid it like the plague"? Yes, but beware, it ain't a pretty
process.


I agree with the AVOID IT recommendations. I have done some core repairs
from below deck and learned a few lessons.

The best way to do it if you can, is to do the core repair from above. Leave
the interior glass alone and cut out sections of the topside deck.. Dig out
the bad core, glass in a new piece and glass over that, building everything
up to the original thickness.

Of course using this method, you will have to find a way to restore the non
skid pattern.. I'm still trying to figure a way to salvage the old patterns
and epoxy them back down onto the repair.. The boats I have worked on using
this method, had to have core repairs in numerous areas and needed new non
skiding anyway..



I did mine from the top. A dremel was used to grind the matching
pattern back into the deck by hand after the top pieces removed were
put back as closely realigned as possible. It is a tedious,
labourious, artistic, messy, rewarding task. Gobs of bog were
injected by refillable caulking tube, and slopped and spread and
reduced and increased, like icing a cake with coins in the icing all
by feel, to make the height of the restored deck the same. I
squeezed out excess and scraped it off the deck before it set up. I
used sandbags (not heavy enough, at first) to press the sections
down while setting up. Sheet plastic was used as a parting membrane
between the glass filler Aerosil mix and sandbags. It was messy. I
found that by driving small screws into places where the replaced
deck / core plywood was low, I was able to adjust the height of the
replaced parts, buttering bog just a little higher than the adjusted
screw heads. There were a few places where the goo sucked back and
required a gravity drip to fill at least most of the voids. I
increased the number of height screws in latter sections to support
the centers of replaced sections. One cannot be in a hurry to
accomplish this.

Too large proportions of aerosil speed up epoxy mix considerably.
Experiment first. I had one or two wads of goo actually go fizzy on
me, kinda like an epoxy foam after it set up. Got damned hot when
that happened. Heat, humidity, thickness, geometery of materials and
sunlight contributed timing snags, too.

Experience means doing it wrong until you get it right.

You could try release wax and poly resin to make a mould of antiskid
to be removed, to press down into the restored deck to redo the
pattern, or try using well waxed (dipped?) expanded metal mesh to
press in a pattern, I didn't try that, but was tempted, as I found a
piece of expanded metal that seemed like it almost matched my anti skid.

It might actually have been better to chainsaw the bad side deck out
completely, and rebuild it starting with a sheet of thin plywood and
plastic film held up under the hole with airbags or props, or
something, I don't know. The eventual extent of the probing for
rotton balsa was unknown at the start. I might have surveyed it
better by drilling some smallish holes from underneath. It was a
pain, but like lancing a boil, neccessary and worth it. My deck
fittings are all set in solid epoxy now, instead of having bolts go
through core, allowing water to enter.

After all, there is nothing half so much fun as messing about in
boats, right?

Terry K

jsheesley wrote:

Thanks guys, I was asking for a friend. I haven't seen the project
yet. Would there be any advantage to thickening the resin?

Oh, yes! Moisten the area first with thin stuff, then lay on the
glass or butter on the bog. You must decide on a method for applying
pressure overhead. Blocks, props, plywood and a garbage bag of air
or a wad of soft foam with plastic sheet parting membrane are not as
good as a real vacuum bag, but mucho better than nought.

It is very difficult to apply vacuum overhead with a porous border
to seal the vacuum to. You could 'paint' on a sealing zone.

Terry K

jsheesley wrote:
Do you guys have any advice, tips or tricks for laying up fiberglass overhead?

Use a garbage bag full of air to press up under areas to hold the
glass and goo in place till it sets up. It ain't vacuum bagging, but
it can help in some situations. You can block up a support, or just
blow it up with a vacuum cleaner, depending on the space available.

For a large splat, maybe you could use a weather balloon and fill it
up with a furnace fan, or start at one end and go section by
section, overlapping while still green.

You can lay out an overhead patch on the deflated bag, and lift it
into place with air pressure.

Terry K

On Thu, 18 Mar 2004 18:06:15 GMT, Terry Spragg
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email

jsheesley wrote:
Do you guys have any advice, tips or tricks for laying up fiberglass overhead?

Use a garbage bag full of air to press up under areas to hold the
glass and goo in place till it sets up. It ain't vacuum bagging, but
it can help in some situations. You can block up a support, or just
blow it up with a vacuum cleaner, depending on the space available.


Just watch out for sharp bits of glass on the old layup. These can be
bad inside a boat

DAMHIKT
************************************************** ** sorry

..........no I'm not!
remove ns from my header address to reply via email

Does Bill Gates dream of electronic sheep?

I'm comming in late on this one. My reader is only showing from this post
on. But.......

If you are in need of doing a large area you might want to "Infuse" it if
you can, or have access to vacuum equipment that is capable of the job. You
could even rent the vacuum pump for the day you need it.

http://www.engr.ku.edu/~rhale/ae510/.../vartmwebsite/