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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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Group: Forum Members
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Visits: 30
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Dravis (20/11/2014)
Your MEKP is diluted/thinned with something that I can not read what is ... Phatalate-something ...  That will almost certainly mean other percentages than "normal" MEKP I think you should try to find out the correct percentage of YOUR catalyst to the "normal Polyesters" that are available locally. Perfect example of "alligatoring" in that picture b.t.v.     My MKEP it's diluted with phthalate, i've seen the composition in the specs of the MEKP that sells in easycomposites website, and seems to be the same. Today it's a little hotter than yesterday, near 21ºC inside the factory, and seems to have a big impact in the curing times too. Now i have to repaint, re-sand, re-do all the fuel tank and prepare it again for apply the gelcoat ....
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