Antifoul time

[Harro]

Its time for my first antifouling on GPR.
There are a huge amount of products available, so would welcome any advice given.
Best Antifouling & how many coats would you reccomend?
Do I need to apply an under coat first or just remove old and apply new?

First reccomendation is Altex Yacht & Boat Paint No5 Antifouling.
All opinions welcome.

[fstbttms]

Whichever product you use- two coats everywhere with a third at the waterline and leading/trailing edges of appendages.

[Pete7]

Find out what the locals are using and if it works copy them. Don't worry about the old stuff unless its really flaky and don't bother with a barrier coat.

Pete

[Harro]

Originally Posted by fstbttms

Whichever product you use- two coats everywhere with a third at the waterline and leading/trailing edges of appendages.

Thanks for advice, I think I'll put 3 coats all over

[Harro]

Originally Posted by Pete7

Find out what the locals are using and if it works copy them. Don't worry about the old stuff unless its really flaky and don't bother with a barrier coat.

Pete

Thanks Pete for your advice, sounds pretty simple.
Regards
Harro

[Dsanduril]

How are you painting? Especially with ablative paint the coating thickness is key. To get advertised life Altex recommend two coats at 145 micron wet film thickness (75 micron dry). This is equivalent to ~7 sq meters/liter. If you roll or brush it is unlikely you can get that film thickness, so more coats may be required.

Application:
No.5 Antifouling can be applied by spray, brush or roller. However, it is strongly recommended that heavy duty airless spray equipment be used to ensure the specified film thickness per coat is applied. Film thickness control is critical to the performance of the coating, as service life is a direct function of film thickness.

Roller: Use a short nap (3/16” / 5mm) solvent proof roller. Additional coats will be required to attain the correct film thickness if the coating is applied by brush or roller. (Typically two spray applied coats (at 75 microns each) requires three roller applied coats to achieve the same film thickness).

Same is true of most antifoul. We're in QLD, use Jotun Sea Force 90 and like it so far (only three months old so no long history) but it took 4 roller coats to get the right dry film thickness.

[Harro]

Originally Posted by Dsanduril

How are you painting? Especially with ablative paint the coating thickness is key. To get advertised life Altex recommend two coats at 145 micron wet film thickness (75 micron dry). This is equivalent to ~7 sq meters/liter. If you roll or brush it is unlikely you can get that film thickness, so more coats may be required.



Same is true of most antifoul. We're in QLD, use Jotun Sea Force 90 and like it so far (only three months old so no long history) but it took 4 roller coats to get the right dry film thickness.

Thanks very much for your advice. It's much appreciated, I was considering 3 coats but I'll roll on 4.
Regards
Harro

[Annie in WA]

I’m facing this choice as well. Any follow up information on the Jotun Sea Force 90? How has it stood up since the original post?