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Ian Mantula
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I've been building my first plug for the air conditioning housing on my Marcos Mantula. While I'm quite happy with the way it has turned out in general I am finding the application of the pattern coat primer to be more difficult than shown in the Easy Composites video. I've tried using a brush and a roller, but can't seem to get to the stage where it only needs minor sanding. There always seems to be new imperfections with each coat. Maybe the working time is too short. I try to mix accurately using digital scales, but never seem to get a consistency that allows the brush or roller marks to flow out. Any ideas what I'm doing wrong?
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Dravis
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I had the same problem with my last batch of EC Pattern Coat primer ... I thought it might be the temperature in my workshop being a bit low .. So I heated the Primer coat a bit, to maybe 25 degrees . That helped a bit, but I still had quite a bit of sanding to do.. The gloss pattern coat was a bit better, but still had brush marks and uneven surface i some areas .. They are good products, but not "perfect" 
"Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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Olivier
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Hi, I used EC Pattern Coat Primer and HI-Gloss to make this plug. After lots of coats I gave up and finished it with the HI-gloss then sanding and polishing to make moulds with EC Uni-Mould range of products. I gave up probably because the part made of plaster and filler was too rough and I sanded trough the primer each time. So it took a long time to have a decent plug. At first I wanted a nice uniform black plug but... Finally plugs were fine and moulds were easy to build.
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MarkMK
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Even with spray application you need to bargain on a fair bit of flatting to get it nice and smooth. I now use a half and half mix of primer and gloss, usually a couple of coats to give plenty of material to flat back. The resultant satin finish that transfers to the mould is then fairly easy to bring up to a good shine with the machine polisher and compound. I just find that this combination provides the best of both worlds in terms of hard finish and (fairly) easy sanding
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Matthieu Libeert
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Ian Mantula
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Thanks for all of the feedback. It's nice to know that it's not just me! I'm getting better at this now, but I guess there is a lot to learn and practice is the only way to improve.
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MarkMK
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If it's of any comfort Ian, I don't think I've yet managed to create a pattern that has a completeley uniform finish to it. Even parts where I'd applied a separate coat of pure gloss have sections where I've gone through to the primer underneath. Not an issue usually as you can polish the resultant mould up to a uniform finish. Have to be wary of bare sections of filler, mind, as these can end up stuck to your mould surface. I have, however, gotten away with gloss directly over bare areas of flatted filler. Probably best to keep the primer flatting to a minimum, to avoid total breakthrough and save the hard work for the final gloss coat, whilst accepting that you might get some patches of primer showing through the polished-up pattern.
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MarkMK
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Bit of a thread revival, but recently picked up a FN4 nozzle for the G100 cup gun and it's much easier to control the spraying with this smaller diameter one. Easier to mist on and avoid the primer/gloss coat running and a more even finish too. Made flatting back more straightforward, so highly recommended over the FN6 nozzle for this application, at least
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Hanaldo
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Have you tried spraying the coatings through a regular HVLP gun? I have sprayed tooling gelcoat with a 2.5mm tip on a HVLP gun and that worked very well, so I would think that these coatings would work too. Easier than the G100 for smaller parts.
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MarkMK
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No, I haven't, 'though considering getting one at the moment to try some clear-coating. I'd have like to have tried the Duratec Sunshield I've seen you mention a few times, but struggling to find it here in the UK
It sounds like this type of gun might work well for applying the in-mould coating on some of the smaller moulds as well, so I might try on those
Cheers
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