Is there a chart of slow/fast hardener % mixture and cure time – I wouldlike to have 60 min pot time to allow the assembly of glass/carbon skins on myfoam cored radio controlled plane wings

When blending the two hardeners to get a "medium", it really is trial and error. 50/50 mix does tend to give you a pot life around the hour mark.

YOu cannot easily calculate a precise predicted pot life as the measured manufacturers pot lives are a range of times at a set temperature. eg Slow hardener at 25C is 95-115 minutes.  You cannot easily be more precise than that.  So when you do it at say 23C or 20C the figures will all be different again! And again you mix a 100g batch versus a 500g batch and you will find variation due to the volume as volume and ability to get rid of heat is a key factor in epoxy exotherm.

So there are a number of variations that limit the ability to give definite figures and tying it down to one rigid set of parameters won't really fit in with most peoples projects so would be again fairly vague data.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant