Aerodux Glue - What is open time
 

Have bought some Aerodux for laminating some teak but the specs don't say
how long you have for positioning once you have brought the parts together.

On Thu, 6 Jan 2005 22:08:51 -0000, "douglashopwood"
wrote:

Have bought some Aerodux for laminating some teak but the specs don't say
how long you have for positioning once you have brought the parts together.


[From Jodel's web site on using phenol-resorcinol AeroDux glue: ]

"The following times are relevant to Aerodux 185:

Shelf life: Here the literature seems to give different information.
Some batches I have used made by Dyno Chemicals, UK, state a shelf
life of 1 year. Others say only 1/2 year. This is true for the glue
component, shelf life for the hardener is indefinite. It should be
noted that once the can is opened, the glue starts deteriorating. It
becomes darker in colour and later lumps appear. So when a can is
opened the shelf life is reduced. Close the lid as quickly as
possible! It is up to your judgement when to throw it away, but as a
rule the glue should be liquid. No lumps are allowed. Aerodux should
be stored in temperatures between +5C and +20C.

Pot life: The time from mixing till application is done. Varies with
temperature of course, but a normal value is 2,5h at 20C. Temperature
should not be lower than +15C (by the way this goes for the materials
to be glued as well) and higher temperatures than +25C are
inconvenient (I understand you aussies). High temperatures make
application a real rat race - more on this later. Pot life does not
increase very much on lowering temperature.

Open time: Now here is the usual criticism against this stuff coming
up. Open time is the time from when spreading the glue is commenced
till the two surfaces are put together. The rule here is that on
putting together the first glue spread should still be clearly liquid.
Open time varies, shortening with increased temperature and increasing
slightly wit increased air humidity. A slightly cool (+15C) and moist
atmosphere is favourable. Still the open time rarely exceeds 15min, so
application of the glue should be swift - certainly an unexpected
problem for the epoxy freaks. On suspicion that the open time has been
exceeded the parts should be scraped clean and possibly sanded before
a new (and swifter) application is done. Friends with brushes is a big
asset when big areas are to be glued! To add to the problem it seems
that open time is reduced gradually with time after mixing.

Closed time: The time between closing of a joint till glue pressure is
applied. Now here things can move more leisurely. Again varying with
temperature, we can have more than 1/2h here. But check that no part
of the joint remains open in this phase - it can ruin your whole day.

Glue pressure time or clamped time: A normal value is min. 8 hours at
+20C. The glue demands medium high glue pressure to produce a sound
joint, to attain this often can be difficult. I use to leave the glued
parts for about 24H with clamps attached. Aerodux can be express
hardened in high temperatures without any side effects. The joint has
full strenght after about a week. "

Hope this helps

Brian Whatcott Altus Oklahoma.