Epoxy vs. Polyester
 

Michiel wrote:
Epoxy vs. Polyester again.

I took the rotozip out and cut out the port half of the inner skin of
the part of my deck that is cored. The balsa there is soaked and a lot
of it rotten. I should have cut this open months ago. Frost clearly
damaged the wood too. The starboard side appears dry and clean, just
delaminated. I'm thinking of addressing the starboard side by
injecting epoxy from inside.

I'll need to give it a week or two for everything to dry out now. Then
I'll replace the bad balsa with divinycell and replace the pieces of
inner skin back. Instead of vacuum bagging, I plan to use truck tubes
to apply pressure. My cabin is only four feet high or so and I think
that with four R20 tubes I can get pretty far.

I'm thinking to use epoxy. The reason for my choice is a slow cure.
I'll be glueing/laminating large areas at once, upside down and I
don't need the resin to set up on me fast.

I've seen how fast polyester can cure and isn't it so that at low
temperatures it may not cure right? And isn't it so that epoxy at cold
temperatures will just cure very slowly? It seems that winter will
work to my advantage - I'll be sure to have plenty of time to position
everything.

Let me know if I'm wrong.

Thank you.

Michiel

Your experience will tell us.

I would make sure it is not too slow, given conditions as you will
need to predict them. A good strong heater inside, and some pink
fiberglass under plastic on the outside, weighted down at the edges
should help.

Could work. One comment seemed to suggest truck tubes have an
unpredictable nature, wanting to skive off, etc.

You may want to consider how to corrall tubes, they seem to have a
need to be free. I think garbage bags might be more co-operative, if
more fragile. If so, an expandable manifold arrangement might be the
key. I see a vacuum cleaner, garden hoses, "y" valves and duct tape
in your future, along with plywood and cross cabin braces of 1x2
strapping.

The vacuum cleaner exhaust will provide some heat, too. You should
provide a small dump hose, to maintain airflow for cooling the
vacuum motor.

If you stretch the tube over a length of 2x4, whatever, before
inflating it, you may be able to get a grip on the deserters, so to
speak.

Technique is the key, practice the only way to get it. Maybe you
should practice with an old, wet woolen blanket on a small section,
first?

Building up a platform under the side deck with old milk crates or
whatever can make the expansion area more stable as you pump up the
wedges.

Glassing under a side deck is like gluing up carpet under the
ceiling of a camper van conversion. When I did that, I actually
ended up with about 4 pedestrian volunteers, drafted from the
sidewalk at the bus stop outside my house, inside the van holding up
the corners for about 15 minutes, until the glue got stiff enough
that it all did not all fall on my head. Did the ceiling in one chunk.

Got tense there, for a while, when the bus came. Two of them stayed
and waited for the next bus. I should have invited some friends. As
it turned out one of the volunteers was a bassist, whom I drafted
for later sessions and to whom I eventually sold the van, a '64 Mercury.