hardner going off ?

[Sinbad2222]

I've got some old fibreglass + hardner but it doesn't set very well. Should I get some new hardner or junk the lot ?

 

[VicS]

Provided the resin still seems ok just get fresh hardener, if you can.

 

[milfordman]

Yes try some new hardner. Anyway what have you got to loose? The other thing is what was the temperature and humidiy. It works better when warm and dry.

 

[ShipsWoofy]

Get the heater on it, it is far too cold right now. I have had some stay wet for a week until I got back and got the heater going.

 

[macd]

Resin does have a shelf-life, but it's usual apparent from its consistency and smell that it's changed. If it seems as it should, it's probably OK.
Hardener is particularly prone to damage by light. Best stored in a cool (not cold) dark place.

 

[snowleopard]

Yes, resin is OK as long as it hasn't turned to jelly but hardener loses effectiveness on the shelf. If it's more than a year old you'll need to add a lot more (but impossible to say how much) best get fresh hardener.

BUT - there are two catalyst systems for polyester resin and they aren't compatible so make sure you get the right one. If you're working with liquid resin it's almost certainly MEKP.

 

[pappaecho]

There are three components to Polyester resin. One is the hardender which is usually a peroxide. The second component is an accelerator mixed with the resin, which then reacts with the peroxide hardener. The third component is the resin itself.
Often it is the "Old resin" which is the problem as the accelerator has stopped working. Go to your resin supplier and explain the problem.