In article , keillorp135
@chartermi.net says...
On Mon, 22 Mar 2010 10:28:16 -0400, I am Tosk
wrote:
In article b949f95b-c2cb-481f-a1db-079c341bb469@
15g2000yqi.googlegroups.com, says...
This is what led me to ask if the same was true for UV cured
polyesters.
So, I am now led to ask if he was correct.
And now we have come full circle.
Sorry to have taken your thread off on a tangent
Hopefully you can get
your answers now that my curiosity has been satisfied
Scotty
I never worked with the uv part. I also haven't worked with these
resins. I did work with people dealing with them in r&d. Polyester
and vinyl ester resins cure by a completely different mechanism, a
free radical chain polymerization. The reactive diluent is styrene
monomer. The reaction is inhibited by oxygen, hence the wax to exclude
air from the surface, or the use of film for vacuum bagging and resin
infusion molding.
This type of reaction is not nearly as dependent on stoichiometry
(ratio of reactants). The initiator and catalyst are all about
providing free radicals to start the polymerization. UV does the same
thing. The concentration of reactive diluent will affect final
properties. Polystyrene ain't that strong.
To the original two questions:
1. styrene monomer will dissolve polystyrene foam like there's no
tomorrow.
2. Don't know. My guess is the initial free radicals generated will
initiate the reaction, the reaction generates further free radicals,
so the parts should cure eventually. I don't know the effect of a
light blocker like carbon fiber, but the stuff would have no
commercial value if at least some useful depth wouldn't cure.
For my fishing boat, I found one using vinyl ester. It's a hell of a
lot stronger and more chemically resistant than polyester. If I build
a boat (would like to, that's why I read this group), I think it'll be
plywood and epoxy. Also, if you're interested in advanced composites,
make sure the resin you use is recommended for the reinforcement. I
recall a rubber modified vinyl ester as being the very best at wetting
Kevlar.
Good luck.
Pete Keillor
Get the book "Build the new Instant Boats" from Dynamite Payson, at
InstantBoats.com. Be sure to get the right book, the brown covered one
not the green cover, previous book simple titled "Instant Boats"
although it is a good read too for the extra few bucks. Just substitute
Epoxy for most of the stuff Dynamite talks about, it was not as easily
accessable and affordable back when the book was written. By the time
you have read it, you will be ready to build your first boat. This was
mine, from the book it's the white one in the top of the page...
http://smallboats.com/boats.htm
Dynamite is great to read, down East and with all the color of his
generation there. Anyone would enjoy this book in my opinion.
Scotty. "No man should pass until he has wet a hull of his own hand"..
(me, I don't remember the first time I said it, who knows, maybe I read
it...)
--
For a great time, go here first...
http://tinyurl.com/ygqxs5v