DIY antifouling

[Boater On Thames]

The first time to do it. The tasks are to remove the unknown old soft antifoul, apply primer, and paint the new antifoul. My preparation list below. Anything missing? Any suggestions? Many thanks.

Surface area size around 44 sqm.

Products:
1. Seajet 015 primer 3 tin (2.5L/tin)
2. Seajet 033 antifoul paint 5 tin (2.5L/tin)
3. Seajet Triple Pack 1 set (500ml) for two 26" propellers

Tools:
4. Electric Sander
5. 80 grit sanding discs
6. Vacuum cleaner
7. Whole-body PPE
8. Rollers & trays

 

[Momac]

Forget dry sanding. I tried it. Very hazardous. Wet sand by hand.

 

[Mr Googler]

Paracetamol

 

[ST840]

Somebody to do it all for you!

 

[Portofino]

Just a light scrape of any loose stuff .Assuming it’s been thoroughly jet washed ?
Never seen folks “ sand “ as such .

masking tape the blue residue less one , the upper finishing line and any other parts eg depth transducer or earth plate or anode bolts .Do not AF the anode bolts they need continuity .Similar the metal flaps leave a shadow for the anodes to gain continuity with the bare metal .
Do not use normal household beige tape a it leaves a sticky residue on the hull when you pull it off .

No real need for a scene of crime suit either , just old clothes. Advise rubber gloves , could be marigolds as they go up your forearms and bin them when done .

The smaller 6 inch rollers and trays + a stick to get low .The fury rollers are better than the sponge , but both seem to do it .
Stir it well with a stick before pouring and pour a bit at a time replacing the tin lid to stop solvents evaporating .
Just roll it on to a dry surface .It drys fast .

Wait a day for the second coat .
Any paint thinners to clean up .

You can add some thinners to the tin if it’s thickened up , up to you .
Save a bit over ( and fresh roller ) for the tripod pads and keel block areas .You do those when the lift comes to launch .Normally they will hoist it and leave it in the slings for this to dry ….about 20 mins before dunking it . Take a scraper to theses areas before slapping them up with AF .

We never use a primer ……that’s for a change of AF possibly or starting a fresh on virgin gel coat .


Acid clean the sterngear and apply what ever you like .Normally a primer , leave a day then what ever on top .
No need to grind or sand anything here just rely on the acid dissolving the accretion which it will , a brush agitation helps .

Get a long handled brush those marigolds up your for arms and proper eye protection industrial type specs with side covers .
Hose it all off with water and allow it to dry before reaching for what ever if any application.

Put new anodes on .

 

[tico]

Top tips....
1. Wear a shower hat.. the ones from hotels are perfect.... dont even think about trying to wash A/F out of yr hair
2. smear your face/ears with vaseline before starting.... that way any splatters wash off easily

 

[Boater On Thames]

Thank you all. Very good ideas. I will put all these into my checking list.

 

[Richard.C]

Somebody to do it all for you!

If the op is going back to gelcoat to apply primer then this is exactly what I would recommend.

 

[jon and michie]

PPE a must - I used a 3m 4251 "bumble bee" dust mask - csi type disposable coveralls - goggles - when sanding back wet the area.
and as other have said get someone else to strip it back

 

[Fantasie 19]

As the others have said .. do you need to remove the old?? Most just scrape off any loose, pressure wash it, and then apply new over old...?

 

[Boater On Thames]

Pressure washing is done by Marina when the cranes out. It's quite clear actually.

I read a web page that said that it's better to remove the old AF and apply a new primer if changing to a new different type of AF. If this is not necessary, then will be good news to me.

 

[STILL AFLOAT]

Most paint suppliers, have a barrier coating. Clean the hull, remove loose bits, let dry.
Paint over the intact antifouling, with the barrier coat.
Once that is dry, you can use whatever you want !
Dont sand old antifouling, its nasty & bad for you & the environment .
Much easier to just paint over it.
How to apply Hempel's Antifouling onto unknown AF
How to apply Hempel Antifoulings onto unknown AF
If you are not sure what antifouling you have on your boat, before applying new Antifouling on top of it, you should seal the surface with Hempel's Underwater Primer. Step 3 Mix the product well. Step 4

International PRIMOCON
An excellent primer for antifouling paint over sanded fiberglass. Primocon® can be used as a conversion coating over unknown well-adhered antifouling paint to prevent cracking of new antifouling paint. Primocon® will not affect the color of antifouling paint. An excellent primer for antifouling paint over sanded fiberglass

 

[Boater On Thames]

Looks like I was overthinking before. Maybe what I need is just a simple scrap and clear up then apply a normal cheap AF. Because when I reviewed the video when the boat out of the water, there is not much thing grow on the bottom even after two and a half years in the water. no shellfish, no weed, just a bit dirt only. The boat mooring upon River Thames here by the way.

 

[Scubadoo]

Just wipe down the old antifouling with a wet sponge and use wet & dry for any flaky bits to smooth off and then for those bits apply a primer before an overcoat. When I change brands of antifouling paint, I email the technical dept and they will confirm if a primer is required as a barrier coat. Obviously if you do not know what is on there, then I would clean up as suggested and apply a barrier coat primer. Hempel underwater primer works well.