Posted by Graham Knight on October 20, 2003 at 10:53:03:
In Reply to: Working in the cold? posted by Dan on October 20, 2003 at 07:03:17:
You're in a similar situation to me Dan, temperatures here in Southern England are currently around 10C (50F) daytime, and down to 2C (36F) at night, and my epoxy is taking noticeably longer to cure!
I think the answer to your question will depend on the brand of epoxy you are using and the specific hardener.
I'm using WEST System, up until a couple of weeks ago I was using their slow hardener which has a minimum recommended working temperature of 16C (60F). I've now switched to standard hardener which has a minimum recommended temperature of 5C (approx 42F), although they do say in their literature it can be used as low as 2C (36F).
I try to do most of my epoxy work at lunchtime, when the resin and workpiece have had time to warm up, and there is enough time for it to cure in the afternoon before it gets too cold. Applying epoxy late afternoon normally means it will still be soft and tacky the following morning so I try not to do it, although it does fully cure eventually. Humidity at night is also an issue, possibly more important than temperature at the moment.
I think you need to look at the epoxy you are using and see what the manufacturer recommends, see if they do a fast hardener for low temperatures, and don't be tempted to just add more hardener as it will have no effect on cure time but will result in a considerably weakened joint.