AF to bare grp

PabloPicasso

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Having stripped off flaky old AF I now want to apply the new antifoul to the GRP hull

Question is, what's the best prep? Lightly abraide Hull (with what grade 120, 80 grit or which). Is it better to prime, or apply to abraided substrate directly?
 
Definitely prime, IMHO. Just a basic vinyl primer (primocon/vinyguard). There may be more ‘technical’ reasons, but when you next come to sand back you’ll want a layer to tell you’re nearly back to gelcoat. 120 grit is fine, if it looks like it needs a key. Make sure you clean (degreaser) before sanding.
 
The technical data sheet for the antifouling you will be using will tell you what priming is necessary. For example the data sheet for International Micron 350 says,
"BARE GRP: Prime with Gelshield 200 for osmosis protection, or Primocon or Interprotect. "

The data sheet for the primer will tell you what preparation is needed. Eg for Primocon it says ,
"Wash all surfaces except STEEL with Super Cleaner.
BARE GRP Sand using 180-220 grade (grit) paper ."
 
At east you are going to read the instructions in advance - too many read them later (when it is too late).

Oddly enough companies product instructions for OUR benefit - not theirs :)

The primer will be recommended by the company whose AF you are going to use, which will obviously (or 99% of the time) be their primer. This may seem like another way of removing more of you money from your wallet to their benefit - but their primer and their AF will be compatible - another primer may not be. So choose the package together, don't buy one and then complain the matching AF is too expensive.

I would choose my AF and then. choose the primer that matches.

Jonathan
 
RTFM then. I'll have to read the data sheet.

How lazy am I
If you'd said which AF you were planning to use someone could have read the data sheets for you, answered you questions and also told you drying times, overcoating times, film thickness, which thinners to use etc etc etc etc

That's what people usually do on here instead of reading instruction manuals etc for themselves. ;)

Don't forget to read the safety sheet as well. :)
 
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