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Jess8bit
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Group: Forum Members
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Hi Guys, I've just experienced my first mold making using Uni-Mould system. My project it to CF copy the "B Pillars" covers of the VW Golf 6 car. These parts are made of plastic, with a glossy black finish. So I made a mould this way : - 4 layers of EC Chemical Release Agent, 30 mn between each - 1 layer of Model 6 release wax, buffed. - 1 coat of Tooling GC - 2 slices of 80g CSM with the Coupling Coat - 2 slices of 450g CSM with the Tooling Resin. Demolding was quite straight forward. Here the problem : To restore the initial gloss of my part, I used EC Mould Cleaner and lint free wipes to clean the part surface, which was initialy covered by the release agent. But all I get is a kind of dull, even whitish in some places, surface. Can't get my gloss back. What happened ? Thanks for helping, I'm afraid I have damaged the part surface but don't know why... as if the release agent, or the mold cleaner, had attacked the gloss... 
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Jess8bit
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Group: Forum Members
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huh huh  no answers Some more details : - I see the "drawing" of light CSM printed through the gel coat, both on the mold and the part. - I tried to clean it with mould cleaner, but was not very effective, as if the drawing was very hard. - On the part, I had to used very hard polishing compound to restore (not completely though) the plastic surface. Does the chemical release agent compatible with plastic surface ? Can we spare the part ? Could the gel coat have been melt with it during the surface ?. Also, I'm afraid I did not wait enough time before applying Coupling Coat. Could this explain my problems ? Is there a maximum time for leaving the chemical release agent on the part surface (before it attacks the surface ?) here is a picture of the part after demolding (the original is a glossy black... :'(   Any help appreciated
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carbonfibreworks
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Hi Jess8bit It looks like the gel coat had not cured enough before you used the coupling coat, if you use the times given on the EC bonnet video you should not have any issues (assuming you have the correct ambient temperature) Regards Chris
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Jess8bit
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Group: Forum Members
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Hi Chris, thanks for your contribution Yes, I really suspect I did not wait enough. It's about 20° in my workshop. I guess a good 3h30 curing time would not be too much (if I remember well, I waited for 3h). I really hope this is the source of all my concerns, cause that one can be solved pretty easily I will give feedback once I'll have done new moulds.
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carboncactus
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4-6 hours minimum, even overnight. I think you gelcoat might also have been too thin. It needs to be half a mil thick and hard enough so that the CMS doesnt print through. Another note, I would have used release wax only, not a semi permanent, and certainly not both.
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carbonfibreworks
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Group: Forum Members
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Jess8bit (17/05/2013)
Hi Chris, thanks for your contribution Yes, I really suspect I did not wait enough. It's about 20° in my workshop. I guess a good 3h30 curing time would not be too much (if I remember well, I waited for 3h). I really hope this is the source of all my concerns, cause that one can be solved pretty easily I will give feedback once I'll have done new moulds. Regards, Jess I leave the tooling gel coat over night and the EC system has worked fine, it is always tempting to try and speed the job up but patience is needed I am the same when it comes to removing parts from the mould but I have leaned to control my excitement . Regards Chris
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Jess8bit
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Group: Forum Members
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Ok Guys, I definitely was too optimistic, I need too wait much more time than I thought. Thank you so much for your inputs. To make it worse, I might have coated a too thin gel coat layer, indeed. It's quite hard to control the thickness by the way. And would you do this in one or two passes ? About the wax, I must say I followed the guidelines in the bonnet video (severaal layers of chemical agent, then 1-2 layers of model 8 release wax). Was it the wrong way ? or maybe I misunderstood something ? |
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carbonfibreworks
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Hi J I use easy lease only and no wax,3 to 4 applications seem to work for me and I make sure the part I am taking the mould from has a very good finish and free of imperfections. Chris
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Jess8bit
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Group: Forum Members
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Ok, seems the wax is not a popular candidate then  Thank you Chris Jess
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Leon
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Hello, The best mould making gelcoat ever is Epoxy gelcoat, as we know hard finish, gloss, and Expensive.
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