Epoxy shelf life question

Mark Davenport

Mark Davenport

Member
I'm finally restarting a Bud Miles BBSB re-glass project that I put on hold in 2012. At that time I bought a few gallons of US Composites epoxy, I did open 1 container each of the resin & hardener for the work i did back then (pumps are still installed). All of the supplies including glass have been stored in a controlled temperature room in my basement out of direct sunlight. It has also changed color from clear to a dark amber. All cloth is in original sealed packaging as received.

Question: Does epoxy have a shelf life? I purchased it in 2012 and not sure if it's still good for finishing the boat.

Thanks,
Mark
 
Yes epoxy has a shelf life. Yes you are beyond the stated shelf life. Yes storage conditions do play a role in shelf life.

That said many folks have successfully used "expired" epoxy. Given the storage conditions you may be a prime candidate to be in that group of successful users.

I would mix up a small batch and glue up a few test joints of various surface areas. Let the epoxy fully cure at least one week. Then do some destructive testing to see if you are pleased with the results.
 
Good idea.
I called, explained my situation.
Support said to mix up a single batch, let it cure in the pot.
If it hardens it's still good. They said customers have done it before.
Thanks,
Mark
 
Mark,
I just went through something similar with U.S. Composites, although ours was from 2015 and not 2012. Hardner had turned yellow/orange. Did a test shot and it cured fine. Followed up by sheathing 16' boat hull- no problem. If you do an internet search you will find a lot of similar stories where people have used older epoxy without a problem.

-Bill
 
I don't know epoxy but other products like loctite have an expiration date. This is a sales tactic as it targets industries such as medical and aerospace who are required to dispose at expiration date due to standards they have to follow.

I perfer talking to the engineers who make the product if I have any doubt. I unfortunately have to deal with this at work more often than I want. We can't afford to operate off of theory.

I like hearing the manufactures advice they provided you. Always the good place to start instead of some wizardly advice online!
 
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My experience with the USComposites Techs... is that they have ZERO experience with USING their products. They only read the documents infront of them. DoNOT ask them to actually think.
 
A quick search is showing us composites as a distributer not a manufacture. Without doing more research this product probably made over seas.
I can see the tech support being useless as mentioned.
 
aerospace who are required to dispose at expiration date due to standards they have to follow.

I have these work requirements, and take advantage of the discarded materials!
 
Working for a manufacturer of many products including epoxy materials - shelf life statements are not there to promote more sales. All major manufacturers exhaustively test product to ASTM standards of which there are many. And epoxy chemistry does change it's strength characteristics over a period of time. If anyone would like to see how epoxies change over time, I am pretty certain I can provide public data that illustrates this.

Shelf life statements are usually pretty specific as to length of time and storage conditions. In my experience, epoxies go anywhere from 2 months in a freezer to 2 years at room temp and everything in between. Products are warranted to be good during this period of time if the storage requirements are met. Outside of this period of time, no more product is warranted and the user of the material should toss it.

As far as the "technicians or technical support" reading off of a written document - they have to do this. They should not be providing answers to questions that they do not have the data to back them up. If they are saying make a small batch and see if it cures and if it does it is good to go - no way would I trust this answer. While it may look cured, there can be many things inside that "cure" that have changed over a number of years.

Personally, I would much prefer to purchase a product from a manufacture who sticks to the expiration dates and whose technical support people read from well written and documented data sheets rather than providing answers on the fly. Next time a technical support person provides an answer that is outside of what the manufacturer reports being good, be sure to ask them for the actual data that will support that claim. I bet the answer changes.

These types of materials are used to make everything from submarines to spacecraft. Can you imagine the liability to the company whose technical support staff went outside of known data and said "sure - if the product cures it is still good to go" and then something catastrophic happens that costs people their lives and the fault of the problem is traced back to bad resin. I wouldn't want to be that employee nor the manufacturer of the resin material.

One person's opinion.

Mark
 
Mark,

Providing the information you have access to would avoid any confusion on epoxy and possibly save some people on here a headache.

To clarify my statements...I deal with iso 12891 and am a six sigma company. Dealing with liability contracts is something I am very familiar with. Also, I design and deal with all stages of manufacturing. We don't sell our own product but build to customer requirements.

I don't deal with tech support and get to deal with the actual developers when we have issues. If you build something that is life threatening you don't call tech support and get the go head. I wish it did work that way and keep liability else where.

Again, I don't know epoxy but I do know 100% expiration dates on other products is bogus!! Some of these companies are in the business to make money.

Due to NDA agreements I can not provide exact names of companies or processes to what I produce. Mark be careful posting online information if you don't understand the legality side of where you work.
 
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Hi Buddy -

Should have added a smiley face to my post. I?ll find the public data sheets and reference later. They may be of interest to some me on this website. I?m at our cabin and have no reliable way to get into our databases.

Trust that I know what I can and cannot post. Been at this game for 34 plus years. I do understand what you say about expiration dates being bogus for some products but this is not the business I am a part of. I was serious about sub and space craft being built with our epoxy products. I also know very well the various epoxy properties and how they change over time. Me personally, I would never use an epoxy resin or adhesive past it?s expiration date as I know how the properties can change while sitting on the shelf. If my life depended upon my equipment holding together, I would spend the money and only use current product.

To each their own.

Mark
 
Mark,

The smiley face would of helped! Its hard to get technical on a forum without knowing the crowd base.

If you can't share the files maybe explaining to us results in simple terms would suffice. I am curious to what degrades epoxy so fast if properly stored? Also, how is the degrading being measured?

Sorry for all the questions but your experience is more than an opinion.

Thanks
 
Mark Davenport said:
Thanks everyone.
I'll do a pot test and bonding test this weekend and update you afterwards.

Mark
Click to expand...

Destructive testing is the about the only way us laymen will have at evaluating the soundness of any epoxy we may have on hand. Even then we will not be able to fully evaluate all the properties designed into any given brand and type of resin.

Mark, You seem like a smart enough guy to figure out what works for you.
 
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