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COZY: MGS H287S (Slow Hardener) Shelf Life

Mike Satchell
 

On 7/18/2022 6:06 PM, Mike O'Grady wrote:

Just under 2 years ago I ordered 6 gallons of resin plus 12 quarts of the subject hardener. The resin arrived, the hardener did not. After waiting for a couple of weeks I called Aircraft Spruce and notified them of my missing hardener. They sent me 12 replacement quarts. All fine and good. I started using them. I’d say ~3 months later (maybe more) the original subject hardener shipment showed up. No cans were broken, absolutely no leakage, but it looked like the shipment was dragged from California up to Washington. There were a lot of heavily dented cans.

 

I called Aircraft Spruce and said I’d be happy to return them, but they’d have to pay the freight. They told me I would hear from them. Months later we had the same conversation. Finally, they said, you can keep them. They have never been opened and have been sitting in my heated (74 degrees) garage ever since.

 

I now need more resin but would like to use the subject hardener. I tried to reach Gary Hunter without success. Reading one of his presentations I am of the opinion that the hardener in the sealed, temperature-controlled cans is just like new, and I can use it.

 

I am looking for feedback from this very knowledgeable DL. Does anyone have any information on older hardener (~2 years) that has been in a sealed can and stored at 70+ degrees? Can I use these 12 cans of hardener?

 

Thanks,

Mike O’Grady



Gary's Presentation:
http://www.cozybuilders.org/Oshkosh_Presentations/2006_EpoxyDoDonts.pdf

Page 14 - "Properly stored, epoxy hardeners are good for many years."
"However, hardeners can have a limited shelf life due to:
-Moisture Absorption
-Reaction with CO2
-Exposure to UV Light
    -causes them to darken or change colors
   

HTH,
Mike Satchell
Tim Andres
 

You call call MGS and ask them, I did that once and found a helpful person there to answer my question. Basically from memory I was told if the hardener is clear, not cloudy or crystals etc it’s fine to use. If yours has been in sealed metal containers I’m confident it will be fine. If any doubt mix some and do a scratch test. If it gets exposed to the atmosphere too long it can develop carbomate which I would be a concern. That’s why the recommendation is store it in sealed cans as much as possible. If still in doubt use it for non structural layups but NOT for micro fill. The stuff is murder to sand. 
Tim Andres

On Jul 18, 2022, at 6:46 PM, Mike Satchell <mike.satch@...> wrote:


On 7/18/2022 6:06 PM, Mike O'Grady wrote:

Just under 2 years ago I ordered 6 gallons of resin plus 12 quarts of the subject hardener. The resin arrived, the hardener did not. After waiting for a couple of weeks I called Aircraft Spruce and notified them of my missing hardener. They sent me 12 replacement quarts. All fine and good. I started using them. I’d say ~3 months later (maybe more) the original subject hardener shipment showed up. No cans were broken, absolutely no leakage, but it looked like the shipment was dragged from California up to Washington. There were a lot of heavily dented cans.

 

I called Aircraft Spruce and said I’d be happy to return them, but they’d have to pay the freight. They told me I would hear from them. Months later we had the same conversation. Finally, they said, you can keep them. They have never been opened and have been sitting in my heated (74 degrees) garage ever since.

 

I now need more resin but would like to use the subject hardener. I tried to reach Gary Hunter without success. Reading one of his presentations I am of the opinion that the hardener in the sealed, temperature-controlled cans is just like new, and I can use it.

 

I am looking for feedback from this very knowledgeable DL. Does anyone have any information on older hardener (~2 years) that has been in a sealed can and stored at 70+ degrees? Can I use these 12 cans of hardener?

 

Thanks,

Mike O’Grady



Gary's Presentation:
http://www.cozybuilders.org/Oshkosh_Presentations/2006_EpoxyDoDonts.pdf

Page 14 - "Properly stored, epoxy hardeners are good for many years."
"However, hardeners can have a limited shelf life due to:
-Moisture Absorption
-Reaction with CO2
-Exposure to UV Light
    -causes them to darken or change colors
   

HTH,
Mike Satchell

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Dale Martin
 

Mike,

We are still using the 287 hardener from 2018, (it's almost gone).  It is also stored in a temperature controlled area with very low humidity.
Just to be sure:  We always have test samples on hand for comparison.  They are a 2 ply layup, 2" by 6" when finished cut. 
Put them in the vise at the same distance and check deflection with 3 different known weights making each weight amount more.  Deflections should be within 0.020" on the new layup to the old layup.
Also, a scratch test is performed on the mixed epoxy.

Be sure to date the test layups and your new test layup pieces for future uses.


Dale
http://www.long-ez.com
=====================>

“The only thing necessary for the triumph of evil is for good men to do nothing.” – Edmund Burke.


On Mon, Jul 18, 2022 at 5:46 PM Mike Satchell <mike.satch@...> wrote:
On 7/18/2022 6:06 PM, Mike O'Grady wrote:

Just under 2 years ago I ordered 6 gallons of resin plus 12 quarts of the subject hardener. The resin arrived, the hardener did not. After waiting for a couple of weeks I called Aircraft Spruce and notified them of my missing hardener. They sent me 12 replacement quarts. All fine and good. I started using them. I’d say ~3 months later (maybe more) the original subject hardener shipment showed up. No cans were broken, absolutely no leakage, but it looked like the shipment was dragged from California up to Washington. There were a lot of heavily dented cans.

 

I called Aircraft Spruce and said I’d be happy to return them, but they’d have to pay the freight. They told me I would hear from them. Months later we had the same conversation. Finally, they said, you can keep them. They have never been opened and have been sitting in my heated (74 degrees) garage ever since.

 

I now need more resin but would like to use the subject hardener. I tried to reach Gary Hunter without success. Reading one of his presentations I am of the opinion that the hardener in the sealed, temperature-controlled cans is just like new, and I can use it.

 

I am looking for feedback from this very knowledgeable DL. Does anyone have any information on older hardener (~2 years) that has been in a sealed can and stored at 70+ degrees? Can I use these 12 cans of hardener?

 

Thanks,

Mike O’Grady



Gary's Presentation:
http://www.cozybuilders.org/Oshkosh_Presentations/2006_EpoxyDoDonts.pdf

Page 14 - "Properly stored, epoxy hardeners are good for many years."
"However, hardeners can have a limited shelf life due to:
-Moisture Absorption
-Reaction with CO2
-Exposure to UV Light
    -causes them to darken or change colors
   

HTH,
Mike Satchell

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