Hi guys i made tons of stuff in wrapping and first time in my life i layed on fiberglass piece carbon then cutted around and brushed to lay second layer- by polyster resin. all time very EVEthing was good but not after 2 days its still not dry???? wtf i thought as other parts ive done never beeen to that AND WHAT IS INTERESTING YOU BRUSH WITH PAPER THAT NOT FULLY CURED SURFACE WITH BLADE AND THEN CAN BRUSH WITH PAPER BUT MOST INTERESTING IF PART WONT STICK TO YOUR HANDS AND YOU THINK ITS GOOD AND PUTTING IN TEMPERATURE LIKE 25 ITS STARTING TO COVERT INTO SAME LIKE BEFORE 5 MINUTES LAYED SURFACE .

Even Poly needs temperature to start the exotherm. Once the exotherm kicks in it will reach around 60 degrees causing it to cure fully. I think your 9 degree working temperature is the problem.

Warren

Carbon Copies Ltd

what Warren tells you is completely true...Worked a lot with polyester in the past and it simply wont cure under 17°C I once did a chair where I used that low temperature to be able to laminate the entire chair, worked on it for 2 hours without anything curing, then bagged it and put it inside and it imediately started to cure once ambient temperature of 24°C was reached... Also polyester will need some mass to cure properly, if you put down a very thin layer of polyester it will take way more time to cure

Matthieu Libeert
Founder MAT2 Composites X Sports
website: www.mat2composites.com

Stick it outside in the sunshine and it will most likely finish the cure in a few hours

If you are working in cold temps, you can get it to go off a bit quicker by mixing it like rocket fuel, something like 5% MEKP and it works

That does work but you have to be very careful especially when skinning. If the exotherm happens too quickly the resin can overheat and discolour. Not really a problem when using a gelcoat but not great for clear coating. Also the resin can be very brittle once cured.

Warren

Carbon Copies Ltd

you know guys problem is why after i put part near heating 25 celsius it starts to act like 5 min before new layer was added like in coming back from begining why is that. when i tryed frp moulding parts and it worked, im thinking maybe carbon eated moisture from air that why no cure fully. and if you touch it wont stick then you start brush with 120 paper and it start to be like not cured surface and like glue to leave on paper. then you brush that sticky surface like i call and brushing good becomes. i dont get. first time this nonsence. and by the way resin in a cup become hard after like 1 hours not more but on part like 2 days/  unrea;!!.

Sounds like what happens when you try to rub it back before it has fully cured. I had the same issue with epoxy once, I got a little bit excited and tried to rub it back after only 12 hours curing. The surface was hard to the touch, but when I started rubbing it back it was very porous underneath the surface, made a huge mess. Left it to cure for the full 24 hours and it was fine, I could sand the porosity that I had caused out of it and it didn't occur anywhere else. 

man i putted near my heating thing for couple minutes resin started to go like bubbles so definitely overheated. one part cured for no tacky surface 3 days unreal. i tryed esterday to lay one layer when was plus 15 so lets see today. my main scary thing from me is i hope carbon not got condensate before i layed it.