TechNetters,
Here are a few provisos though.
1) Chemistry still happens, so grain and intermetallic growth will still
happen although slowly since your samples are presumably stored under room
temperature conditions.
2) Surface oxidation will occur but for tin based solder this is not an
issue. Could be an issue if you are talking about iron based samples and
your storage conditions are on the moist side.
3) I have seen the growth of lead whiskers out from the surface of
cross-sections of samples with high lead solders.  I believe this was the
result of both the pressure and temperature of the curing epoxy, so not
likely to occur in RT stored x-section samples. However, I have seen enough
change in the surface of more traditional tin/lead and lead-free samples
that a re-polish with the finest grit was required.

Regards,
Bev. 

-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Stadem, Richard D
Sent: Monday, January 6, 2020 2:33 PM
To: [log in to unmask]
Subject: Re: [TN] storage life of PCB microsection mold

Absolutely!


-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Bhanu Sood
Sent: Monday, January 6, 2020 11:10 AM
To: [log in to unmask]
Subject: Re: [TN] storage life of PCB microsection mold

And the microsectioned/prepped surfaces are protected from internal and
external contamination.


> On Jan 6, 2020, at 11:44 AM, Stadem, Richard D <[log in to unmask]>
wrote:
> 
> I would assume it is just about forever as long as it was potted within
the shelf-live and pot life of the mold potting material.
> 
> 
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of R Saravanan
> Sent: Monday, January 6, 2020 10:16 AM
> To: [log in to unmask]
> Subject: [TN] storage life of PCB microsection mold
> 
> Dear all,
> 
> What is the storage life of the pcb microsection mold . How long we can
preserve.
> 
> I am using long curing resin.
> 
> R.Saravanan