And be careful of the formaldehyde generated by phenolic during cure in
closed quarters as it can knock you over with its pungency.
On Sat, May 2, 2020 at 1:57 PM Norman Yarvin <yarvin@xxxxxxxxxxxx> wrote:
On Sat, May 02, 2020 at 08:58:19AM +0200, Uwe Klein wrote:
Am 02.05.2020 um 03:41 schrieb Norman Yarvin:
On Fri, May 01, 2020 at 08:52:41AM +1000, Troy Prideaux wrote:
Bill, the resin *was* (as in, a long time ago) manufactured here and
probably hasn’t been available anywhere for some time, what’s more it
requires a gradual stepped post curing process that (upon
subsequently hearing the location of the repair) might be impractical
for this repair [...]
With phenolic resins normally requiring a combination of heat (to get
the reaction going) and pressure (to keep the water produced by the
reaction from boiling and turning the piece into a foamy mess), it's
no surprise that this is rather a rare product. I suppose they
overcame those difficulties by some sort of creative chemistry and/or
that post curing process, but it couldn't have been easy.
I've only ever worked with wood phenolic glue.
They need pressure for a narrow glue line.
( good bonding but not good fillers, epoxies are easier to work.)
They like some heat.
They don't start to foam with lack of pressure.
i.e. squeezed out glue is solid after setting not a foam.
(mechanical properties v )
Might that glue have been resorcinol- rather than phenol-based? It's
very similar chemistry (resorcinol differs from phenol just by one OH
group, and in both cases formaldehyde is the other reactant), but it
can cure at room temperature. And of course at room temperature the
water generated doesn't boil.
It might be suitable for this chipped liner repair, though that didn't
sound like it really needed repairing.
