Hi John

 

All amine hardners will give off ammonia (amine/ammonia...you get the picture) so there isn't any truth to that rumor about only "bad" hardner gives off vapors.  Listed in the Hysol specs you should have a Shore hardness, probably D scale.  Fillers make the hardness variable from one type to another so if you tested say a Jeffco plain epoxy and then mixed in fillers, you'd probably get a difference.  They may have this listed online, check the Hysol website.  You might ask them if they can run the hardness test for you.

 

As a reference, I had some epoxy that's about 15 years old tested recently and it was fine. I even tested some 25 year old epoxy gloss paint a few months ago and it was fine!   Just be sure you seal the containers well so the shelf life is what the manufacturer is on the hook for and can still see no degradation of the properties.  Generally they are a lot longer than stated.  Of course chemistry will vary greatly and alter the real shelf life significantly as will storage conditions.  It's only a guess but I'd say the Hysol is most likely good for 5 years or longer with no problem but just be sure to test!

 

One thing I will be doing for my ES is batch testing the epoxy and keeping retains.  It is required for certificated aircraft but of course not experimentals. However when it comes time to sell my baby, a well documented, tested and saved set of epoxy castings will help sell the plane I'm convinced.  It shows you have used good material thoughout the plane and that you have a high level of construction standards.  And I won't feel one bit bad about having verified that all of the adhesives used were within spec.  In fact, I've written a maintenance manual for the construction of the plane which outlines sampling and testing, mixing specs and techniques, etc.  This is just stuff that I normally do when mixing my own resins and making composite laminates and adhesive bonding.  It doesn't alter certification for the plane other than showing the FAA that you know what you are doing (or not!) but again, it shows potential buyers later how proffesionally you approached the project.

 

If Hysol doesn't want to be bothered, give me a call at (510) 476-2150 and I can probably get some names that may be able to help with testing.

 

Dan Newland