On Fri, 13 Mar 2009 11:01:05 +0000, The Natural Philosopher
wrote:

Matty F wrote:

It's a very liquid epoxy resin with a hardener added in a 5:1 ratio.
The amounts have to be precise or it won't set. I coloured it with
blue and yellow pigment because I didn't have green.


Then it possibly isn't epoxy,.

Epoxy is not 'hardened' by a catalytic hardener,. It sets by direct
chemical reaction between two precisley mixed constituents. The mixture
ratio is crucial.

So why don't you consider '5:1' to be precisely mixed? There are at
least two major manufacturers of epoxy resin systems that specify a
5:1 ratio, West and SPS, there are also resin systems with 3:2, 5:2
and 1:1 ratios.

I tried a fast hardener but it got very hot and started smoking so I
had to dowse it in the sink.

That's very polyester like behaviour.

Epoxy can also exotherm, when this happens, other than a lack of
styrene smell what you observe during such an occurrence is identical,
and the precautions taken to avoid exotherm are identical regardless
of whether you use polyester or epoxy resins. You could take any one
of dozens of resins of varying chemistry and by intentionally
introducing process errors during mixing or application and they would
all without exception exotherm with an ambient temperature of 15 deg
C, yet you could also mix and apply those same resins in a different
manner and they wouldn't exotherm when the ambient temperature was
raised to 25 deg C.

Also a 'fast hardener', when used as specified by the manufacturer is
no more prone to exotherm than a 'slow hardener'. All it requires is
attention to ambient temperature, mix volume, mix vessel geometry,
application vessel geometry, layup thickness, and curing temperature.

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