Tooling Gelcoat

Hello! I used tooling gelcoat for mould production. I applied a first layer onto the plug with 2.5% MEKP with a brush and let it harden overnight for about 15 hours at a temperature of 20 degrees Celsius! It hardened but if I press hard with my nail, a mark remains and if I pull verry hard with my nail, a little gel coat remains under the nail. Is it normal for it to be like this on the surface?? Can I continue with the second layer and then with the other layers of reinforcement??Thanks

 

Completely normal.

Continue as planned.

 

Thanks!!Have a nice day!!

 

Thanks!Have a nice day!!

 

Hello again!If I put the reinforcements after 24 hours onto the gel coat it's ok for the adhesion or its to much time?

 

Ideally you ought not leave it much longer as there is a window in which the bond will be at it's maximum.Really, you may have already exceeded the delay for the best bond.A lot of people begin he first laminate as soon as a gentle touch with a finger doesn't leave a coloured mark on that finger.

 

Hello!Thanks!So there will be no bonding or a weaker one prone to delamination

 

You will still get a bond and it may be quite good,but the optimum time for the next laminate may have passed.In my region,we try not to leave exposed gelcoat more than 24 hours before the first laminate.

 

It was under the 24 hours.I think that's ok?

 

I wouldn't expect the bond characteristics to go from 100% to zero the instant that 24 hours have passed-would you?There will always be a mechanical bond but the chances of additional chemical bonding will be deteriorating gradually,so you need to get on with the first laminate and remember not to apply too many plies of glass in one session.

 

Thanks a lot for your answers!!

 

I be always been under the impression that tooling gelcoat was formulated to be used on tje plug, where extensive sanding and fairing is expected to take place to avoid having defects transferred to the actual mold surface.

 

It’s not ideal for the gelcoat to stay soft or leave marks after 15 hours. Wait longer until it’s fully cured before applying the next layers to ensure proper adhesion and avoid defects.

 

It is ideal for the gel coat to not be fully cured on the surface. Every important aspect is better if you can still leave a mark with your fingernail.