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Hi to all. It's my first mould using UniMould system. I follow exactly the tutorials and indications for making the mould. For the first step, i have bougth locally an MEKP catalyst ( i have attached the image ). I have applied a thin layer of gelcoat, and 4 hours later, another layer. After that, i have wait to the next day to let it cure, but the surprise was, that the part was totally ruined when i arrived next morning ( i have attached another image ). At that time, it had been drying for about 15h. The gelcoat has reacted with my part ( a motorcycle fuel tank ), producing great wrinkes all around the part. The tank was just finished, laquered and polished with PPG clear coat, and it has been drying for a week before I apply the gelcoat. The room temperature was about 17º in the day, and about 13º overnight. I have made a test yesterday, using 3 small mixes, one in 2%, another in 5% and a extreme one at 10%. The 2% mix, seems to never cure, it has been applied for about 20h right now, and keeps almost fresh. 5% looks nice, it's tacky in the surface and cured in the inside part, and the 10% mix its fully cured. I think the problem has been that the mixture at 2%, has react because it has been applied over the clear coat too much time without cure ( i look at it 6h after the application and it has no wrinkles at all ), producing the wrinkles at the end. The question is, it's safe to work at 5% ? Do you think that the problem it's another one ? Thanks in advance, and sorry about my english.
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Unfortunately Dravis is right about the temperature and the issues with the plug surface.
You really need to be at 20C or above throughout the cure time.
The alligatoring is classic reaction by the gelcoat to a surface it doesnt like.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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Warren (Staff) (20/11/2014)
Unfortunately Dravis is right about the temperature and the issues with the plug surface.
You really need to be at 20C or above throughout the cure time.
The alligatoring is classic reaction by the gelcoat to a surface it doesnt like. The fuel tank surface its a PPG clear coat, tipically used in a lot of vehicles. In the test i made yesterday, there were no problem, because it has cured "in time". I think the problem was that it doesnt cure, and more than 12 hours over the clear coat has cause the reaction. Warren, it's the phtalate contained in the MEKP i used a problem or it doesnt matter ?
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