To add to that, the Araldite 420 I located in the U.S. seems to have a
different shelf life than the one I got from the UK. This is Araldite
420, not Epibond 420. The vendor (http://www.adhesivesforsale.com)
said his stock expires in 6 months. The original bottles were
apparently labeled for only 12 month expiry. So the expiration dates
are most likely related to regional issues such as liability and
record-keeping reasons more than the chemical itself.
On Thu, Nov 7, 2013 at 12:30 PM, Andrew Sarangan <asarangan@gmail.com> wrote:
> Nigel
>
> Thanks much for your input, and the link to the strength data.
>
> I had a similar issue with Aeropoxy, and was told by one of their reps
> that it should not be a problem. The only change I have noticed is the
> hardener (PH3660) turns red and eventually very deep red despite being
> in the original sealed container. Although the bond strength appeared
> to be good, the hardener is pretty cheap and easy to acquire
> ($35/quart) so that is what I did. But the Araldite 420 is pricey. It
> doesn't seem possible just buy the hardener separately. The resin and
> hardener comes as a single kit, and I was quoted $900 for a single can
> from the only US source I could find.
>
>
> On Thu, Nov 7, 2013 at 9:02 AM, nigel_graham@m-tecque.co.uk
> <nigel_graham@m-tecque.co.uk> wrote:
>> Andrew,
>>
>>
>>
>> I read your post with interest as I have pondered the same question.
>>
>> I bought my first kit in 1994. It was supplied with two cans of Redux, one
>> of which I opened and began using until the project ground to a halt (like
>> so many), the other remained sealed.
>>
>> Long after the use-by date, I resumed construction and mindful of the age
>> of the Redux but curios as to how it degraded with time, I contacted
>> Ciba-Geigy and was lucky enough to be able to speak to one of their research
>> chemists.
>>
>> Refreshingly honest, he assured me that both resin and hardener are totally
>> inert and very stable and that, in theory, it would not degrade over time.
>> When I asked why they advised a 36 month use by shelf-life, he answered
>> that as epoxies were relatively modern, there was no historical evidence
>> of any degradation and that it was only added to placate various regulating
>> authorities. He did warn that the yellow resin would most likely
>> crystallize over time, but that chemically it was unaltered and a gentle
>> warming in a water bath would restore it to its original liquid state (the
>> opened can subsequently did, as predicted, and was restored exactly as
>> advised).
>>
>>
>>
>> Returning to my two original cans, both had a use-by date of October 1998
>> I still have them and continue to use them today, 18 years after
>> manufacture. It works perfectly.
>>
>>
>>
>> This also remains true of other epoxies. My SP Systems Ampreg 20 still
>> performs perfectly (expiry 1999) and my super-expensive Polyfibre
>> Super-Fill works perfectly too (expiry 1999).
>>
>>
>>
>> Before the finger wagging begins, I should explain that I acquired the
>> mortal remains of a cart-wheeled Europa to allow me to develop repair
>> strategies for the compression fractured ailerons, flaps and tail. The
>> time-exd epoxy was used on these. The resulting components are
>> indistinguishable from new-build parts. I keep test samples of each resin
>> mix in clear plastic egg-boxes, with encapsulated paper slips listing date,
>> batch no and component-used-on in each compartment for trace-ability.
>>
>>
>>
>> Here is a link to the Redux (Araldite) 420 data sheet listing the target
>> peel strength test figures:
>>
>>
>>
>> http://www.ambercomposites.com/downloads/datasheet/araldite-420-tds-v1.pdf
>>
>>
>>
>> atb
>>
>>
>>
>> Nigel
>>
>> On 06/11/2013 17:54, Andrew Sarangan wrote:
>>
>> Snip .....I am hoping someone can send me a small sample of unexpired
>> Araldite
>> 420 for comparative testing.
>>
>>
>>
>>
>>
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