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Author Topic: Preparing GRP Hulls  (Read 3204 times)

Stavros

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Preparing GRP Hulls
« on: January 02, 2009, 11:56:35 PM »

Right then PLEASE do yourselves and others a BIG favour by listening to what I have to say on hull prep,believe you me it works.
Right then this thread has come about due to me spending the day with a blunt instrument scraping paint off a hull,and believe you me this is the fourth in a week all due to one thing BAD PREPARATION.
But i hear you all say well i do it this way and it works for me,all I can say is ............does it
Right then when a Grp hull is badly prepared it will not show up straight away,it is only when you scratch the hull or need to repaint it that problems occur.What happens is that water gets underneath the paint and you get loss of adhesion,not apparent to the human eye,unless of course ti is peeling off in great chard's!!!!!!!!!!

HULL PREP

1  Go out and buy youself a gallon of spirit wipe ..you gonna need it
2  Wash off all traces of mould release wax.Wash off the hull with SPIRIT WIPE to get rid of the mould release wax .Fairy liquid not good enough.
3  Start rubbing down the areas that you need to work on,ie the inside of the hull with 80grit to get a key for the glue to adhere to,outside where the shaft and       
    rudders come through 180grit
4  Wash off with spirit wipe and dry
5  Rub down the hull with 180 then 240 then 400 ready fro the PRIMER yes you do really need this stuff,simply fro the paint to stick to!!!!!!!!!!!!!!!!!!!
6  Wash the hull down with panel wipe
7  Prime the hull
8  Rub the hull a guide coat of satin black LIGHTLY not a full coat
9  Rub thus down with 600 or 800
10 Rub the hull down preferably DRY with 600 making sure that you get rid of All the black guide coat
11 Wash the hull with panel wipe
12 Paint it with colour of your choice


I know the well it works this way for me brigade will say it but hey come on do you in say 12months or less want the hassle of oh what do I do now,My guess is NO



Stavros

2 threads combined to complete this one

Bob

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Proteus

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Re: Preparing GRP Hulls
« Reply #1 on: January 03, 2009, 08:35:26 AM »

Just one point , if you have used any evo-stik contact Adhesive or similar , white spirit is used to clean it off and will soften it and it may loose strength also SOME plastics will soften as well, test it first.


Proteus
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Colin Bishop

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Re: Preparing GRP Hulls
« Reply #2 on: January 03, 2009, 09:02:15 PM »

Topic cleaned up

Footski's post removed in error which read:

Sound advice. I followed Stav's system on my Lady T and got the best finish I have ever had on a model.   

Colin
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wallace

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Re: Preparing GRP Hulls
« Reply #3 on: January 20, 2009, 10:00:40 AM »

very good tips in getting the hull ready but i dont used white spirts good soap and water
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mike_victoriabc

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Re: Preparing GRP Hulls
« Reply #4 on: January 20, 2009, 02:07:19 PM »

Spirit Wipe - is that similar to Acetone?
Just about to clean up a glass hull, good timing!
Thanks for continuing to post this type of info.
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Stavros

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Re: Preparing GRP Hulls
« Reply #5 on: January 20, 2009, 10:31:16 PM »

No Mike acetone is not similar to Spirit/Panel wipe at all BUT you can use Acetone to clean a GRP hull if it has NOT been painted,if the hull has paint on well my advise is DONT.Mike as you live in Canada try going to a body shop and scrounging some, of even a car paint supplies who will sell you some



Stav
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mike_victoriabc

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Re: Preparing GRP Hulls
« Reply #6 on: January 21, 2009, 12:12:35 AM »

Thanks for that - I would presume acetone on paint would make more than a mess of the job!
I'll check with my friendly bodyshop.
This hull appears to be out of the mold, needs quite a bit of trimming and cleaning up. The deck is the same, fits just inside the hull.
Once I get organized, will post a couple of photos.
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porsche356supersport

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Re: Preparing GRP Hulls
« Reply #7 on: February 23, 2009, 05:03:24 PM »

Hi there, I've got an ABS yacht hull that I wish to paint.

When you say Spirit Wipe do you mean White Spirits?

Based on your instructions can you answer my questions.

5  Rub down the hull with 180 then 240 then 400 ready fro the PRIMER yes you do really need this stuff,simply fro the paint to stick to!
   Presume this instruction is for the outside - should the sand paper be wet or dry?  How much pressure should I apply and how do I know I've done it right?

6  Wash the hull down with panel wipe
    Is it not possible to use White Spirits for this process, sorry it's just that is what I have available

7  Prime the hull
I intend to paint the hull a dark prussian blue and was going to use a grey automotive spray can primer; will that be ok?

8  Rub the hull a guide coat of satin black LIGHTLY not a full coat
Satin black; what is that exactly, do I need to do this on my hull?

9  Rub thus down with 600 or 800
Again should this be wet or dry sandpaper; same questions about pressure applied and knowing when it has been done right

10 Rub the hull down preferably DRY with 600 making sure that you get rid of All the black guide coat

Thanks for your assistance.
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