I am doing a over lay on some parts it went well the first 2 layers of resin. I am using the silmar 249 resin and the surface wax. On my last layer of resin i ran out of the mekp but i found some old ones mayb about 3-4 months old. and after the last layer of resin i left it over night to dry. The next morning the part still looks wet and tacky so i left it another day. and it got a little dry but still looks takcy and as i started to sand it its was sticky and didnt sand right. Is this because i am using the old MEKP or something else? thanks
If the MEKP was left exposed to light and air, some of the ingredations could have evaporated.
There is also winter (more reaction) and summer (less reaction) MEKP.
Only use the surfacing wax / agent for the last coating as that is the only time you need to use it.
Well today i used a brand new MEKP and i notice it dryed and made the wax additive work better. Also i have been doing some overlay with the wax additive as the last coat, and i have also used the wax additive for every coat i just sand it down before every coat. I notice this way it builds the layer faster and thicker. Is this a wrong way of doing it?
the wax can cause intercoat adhesion problems, it doesn’t always but can. IF you have to use the waxed resin for all coats, either lay wet on wet or let them fully cure, wash with ammonia, sand and lay another. The ammonia is to remove the wax that has migrated to the top, just sanding can just smear the wax.