I usually pour the remaining amounts of resin and hardener that I can not get with a syringe into a 50 ml, clear plastic, screw cap jar with a wide mouth. The wide mouth allows easy access to "syringe out" the remaining amounts of finish.

I noticed an old jar I had laying around for a couple of months and the hardener has turned much more yellow than the hardener that came in the original bottles.

I don't know what my wide mouth jars are made of, but they have the flexibility of polypropylene, but are as transparent as polystyrene. I am confident the jars are clean before I pour in the resin and hardener into their respective jars.

Ralph, what could be going on here? A reaction with light because of the very transparent jar material (only fluroescent light exposure)? The material the jar is made of? Comments?

John
I have bumped into this phenomenon before and have a ready answer for the cause and remedy. The remedy is do not put your LS type hardeners into a wide mouth jar, unless you store it in a vacuum. The surface area of a wide mouth jar is to much surface air contact for the amine to handle. These amine's are purchased from the manufacturer -- shell chemical co. and Pacific Anchor, are the biggest suppliers. Both suppliers know of the problem and claim it is being remedied but I haven't seen any results yet. In the meantime, keep your hardener in a small mouth bottle and out of the direct sunlight. You will not notice any difference when you mix and use the materiel and its light stability when cross linked with the epoxy resin is the same. We modify the amine extensively before packaging for the LS Supreme hardener. This modifying helps considerably to slow down the process, but putting it in a wide mouth jar will speed it up again and negate our efforts. In the future we may have to put out a warning on the instructions to that effect.

The first time I saw this, I thought that someone was trying to pass off a urine sample on me. Careful analysis proved otherwise..

Ralph

Thanks Ralph. I knew you would have a logical answer. You are right about the urine.

OK, my friend. Now, without resorting to drilling a hole in the cap and @#$%& out the hardener and resing that way, what other recourse do I have.

Are the folks at U40 perhaps working on a clever packaging alternative?

Ralph I recently spoke to someone at Rod Builder mag to get some info on rod building and your name came up and from the emails Ive seen youre the guy Im looking for .
first Im rebuilding not building , A utica fly rod three piece.
what do I use to refinish the color, it was a bit rough so Ive lightly sanded but want to change it from black to blue or green, is that out of the question .

Hardener begins to darken because of moisture in the air. Having been in the boat building industry for a number of years I have seen it happen many times. Although the color may not be desirable, it will not effect the strength and durability of the cured product. Keep air exposure to a minimum with the hardener.

Jason