gel coat

[amcc]

Hi I,m back, well I have brushed the Gel Coat onto my Mirror, so far so good but I think thats the easy part I now have to get the brush marks out and this is proving very difficult, I have tried 240 grade wet & dry but it,s very slow, the Gel Coat seems to be shaded and takes forever to make it uniform is there a quicker method, I would be greatful for any advice.

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[waverider]

How much of an area have you coated with gel coat?

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[MLBURGE]

'yeah' did say put it on with a roller lots of thin coats.

you can try a courser grade down to 60 wet and dry and you can still go through the grades to get a good finish but be carefull you don't cut through the gelcoat. Unfortunatly it is going to be very labourious to cut it out electric sander may work but i find by hand is can be just as quick.



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[waverider]

Hmmmm.....sounds like a lot of hard work....especially as gel coat (Polester Resin) can be sprayed on!.....the only advice I can give is: use 3mm's wet and dry using a rubber block and a bar of soap to prevent the paper from clogging.....do not use too course of grade as this will put deep scratches in the surface that a machine will not be able to polish out .......the finishing grade should be at least 1000 !

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by waverider on 06/09/2004 21:50 (server time).</FONT></P>

 

[grahama]

Wacerider,

whats is the purpose of the soap and how exactly is it used?

thanks in advance

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[waverider]

Well if you are using wet & dry with water....everytime you rinse the flatting paper to prevent the grit from clogging, just rub a little of soap on it before returning to the area you are wet flatting........you will also find by using this method with a bar of soap the grit will work better too. Also when I recomended 3MM wet or dry, although it cost's a little more it last's longer and is usually the only paper used by the pro's.

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[gjgm]

well, quicker way is going to be with a dedicated polisher/sander and cutting compound.. but how big a project was this to start with! Did you mix the gelcoat properly? there shouldnt be any shading. Do you know if it was gelcoat or topcoat (ie with wax added) as the latter will dry matt and needs to be polished thru various grades, ending with a 2000 grade polish if you want a perfect gloss. maybe your shading is just parts remaining matt , and others starting to polish up a bit? One trick is the spray black car paint over the top, as, when you start cutting back, you will see where you are ending up with high (black removed) and low (black remaining) spots.

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[waverider]

Quote: One trick is the spray black car paint over the top, as, when you start cutting back, you will see where you are ending up with high (black removed) and low (black remaining) spots.

Yes thats good advice although just dust the spray on and not spray too wet or heavy....in the trade we call it a guide coat

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[MLBURGE]

a few drops of washing up liquid in the water will help aswell.

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[waverider]

To be quite honest if it were me I would start again!....first with a D.A and dry sand it all down......prep it then spray it!

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[kingfisher]

mylar

You should have finished off your gelcoat spray/paintjob by placing a Mylar film over the finished surface. Once the gelcoat has hardened, the mylar comes off easily and leaves a near-finished surface

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[amcc]

Hi, Thanks for your reply, you say to spray the Gel Coat but when I asked my GRP supplier about spraying he said it would not be possible,so if you could help me here, how do I thin it and what kind of gun do I need

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[amcc]

Hi It was Gel Coat with wax added and I am not sure what caused the shading, the job has become a nightmare, the first coat I put on did not harden so I had to get it all off again and I dont know if this is where the shading is coming from I dont want to keep rubbing, might go right through the Gel Coat. I might just leave well alone, so thanks for getting back to me and also everyone else who did, by the way it,s the gunwhale of a Mirror Dinghy so not very much

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[waverider]

Gel coat can be sprayed with a 'High build spray gun'........depending on what kind of gel coat you are using....The regular gel can be thinned out with resin.....using the right amount of catalyst to prevent the gel from curing too soon and recking the equipment which after use has to be thoroughly cleaned with acetone!

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