Expired Epoxy Systems

I purchased a few cartridges of Loctite E-120 HP Hysol epoxy a few months back, and just now realized that they have passed their expiration date. They have been stored out of sunlight, at or below room temperature. I was planning on using it for a fairly high performance project, but I don't know if this would negatively affect the properties of the epoxy.

David

I use a lot of expired epoxies. It all depends on how and where you plan on using it and what you mean by 'fairly high performance project'.

a 98mm min dia with a N5800 using it for fin filets and no tip to tip? I'd buy some new stuff.

a 2.6" rocket with a 38mm motor mount with flying on a big J motor..I'd use expired epoxy.

I've used expired epoxy on tip to tip up to mach 2.7.

Tony

dnp said:

I purchased a few cartridges of Loctite E-120 HP Hysol epoxy a few months back, and just now realized that they have passed their expiration date. They have been stored out of sunlight, at or below room temperature. I was planning on using it for a fairly high performance project, but I don't know if this would negatively affect the properties of the epoxy.

David

Click to expand...

It depends on how much past the expiration date.
I wouldn’t hesitate to use it if it’s within a few years. The expiration date might affect their guarantee, but all manufacturers include some margin of safety. I doubt the properties would change substantially in a short time.

tfish said:

I use a lot of expired epoxies. It all depends on how and where you plan on using it and what you mean by 'fairly high performance project'.

Click to expand...

Mostly carbon minimum diameter flying on a Loki L-2050LW.

I believe they expired in March or April, so it sounds like they should be fairly safe to use.

David

When I ran the HAZCOM program for our shop it wasn't uncommon to receive shelf life extensions on unopened epoxies. The expiration date is normally pretty conservative. They based their approvals off of tests from epoxy with the same lot numbers, so I'd mix some up and test it on some scraps. If it cures at a normal rate and doesn't show signs of anything weird, I wouldn't be concerned.

I would not hesitate to use the epoxy.

I've bought gallons of expired epoxy. Generally speaking, unopened containers that have been in climate controlled dark locations should last well past the expiration date. The epoxy part has the longest life; it is the Part B or curative that is sensitive. For the epoxy part, if there is any crystallization, warming it up takes care of that. If you question the curative (darkened, change in viscosity, etc) then you could replace just that component.

It should last longer in metal cans than in bottles.

Gerald