A friend has asked me how to anti-foul his aluminium runabout (15ft alu open boat with 50HP outboard).
It was previously on a trailer, but now he wants to keep it on a mooring.
He knows that you use aluminium-specific antifouling paint - like Trilux 33
What he doesn't know, however, is what the best "tie coat" may be.
The Quintrex hull is currently painted with factory glossy hull paint, still in good condition.
The paint shop assistant recommended using International Primocon as a tie coat, than overcoat with Trilux 33.
A neighbour suggested .just a light sand with 80 grit, then Trilux directly over.
Any opinions from the Seabreeze forum?
Thanks
Karsten
Select to expand quoteRamona said..
The paint shop assistant was spot on.
That really depends on how the "factory gloss paint" was applied, that being the foundation for anything applied over it.
When the hull is press formed in the die it is usually done with some form of lubricant applied. Did the factory degrease the alloy first, then acid wash, fresh wash and then apply an etch primer such as PA 10 before applying the "factory gloss paint"...??? I seriously doubt it.
I was going to antifoul my 10 ft tinnie but never got around to it or had the need, however I did do the full preparation for it as in wet and dry sand, acid wash, fresh wash, PA 10 and then two coats of Hempel Hempatex Alu Primer 1630.
Despite not coating over the primer with antifoul the tin of which is still on my shelf and it being Hempel Antifouling Mille Dynamic Alu and despite lots of use of the tinnie over the last 10 years, the primer is still looking like new. The primer is such a close colour match to the aluminium you would swear it is not painted.
I will take a photo tomorrow and post it.
Select to expand quoteGKandCC said..
Expensive way to keep a 15ft tinny, buying a trailer is just a year's fees. 
A 15 ft tinnie on a mooring is just asking to be stolen with it's 15+ hp outboard attached which you are not going to lug home in a row boat after each time you use the tinnie are you...?????
Primicon is just an aluminium based underwater primer similar to the other brands used for the same job. I use Jotun but it's just the same.
Select to expand quoteRamona said..
Primicon is just an aluminium based underwater primer similar to the other brands used for the same job. I use Jotun but it's just the same.
Hempatex 16300 aluminum is the same as Primicon, that's what I was told at the Boat Paint shop. The gentleman there said you could mix the two together in a can without a problem as an example. Hempatex 16300 cost me $100 for 5 lt
Thanks gentlemen for the good detail on aluminium primer options and products.
It sounds like it may depend on how thick the factory paint layer on the bottom is - if it is reasonably thick and in good condition, I imagine a "tie coat" rather than etch primer would suit, but for all other circumstances one of the Alu primers mentioned sounds like the way to go. Will suggest he does some scrape tests.
Select to expand quotecisco said..GKandCC said..
Expensive way to keep a 15ft tinny, buying a trailer is just a year's fees.
A 15 ft tinnie on a mooring is just asking to be stolen with it's 15+ hp outboard attached which you are not going to lug home in a row boat after each time you use the tinnie are you...?????
It's an approx 400kg tinny with 40HP outboard. It's a 20km round trip to a boat ramp but short walk to the shore where he would use a small dinghy to row out.
He feels parking the tinny on a trailer on street is risky too, and he has an outboard locking device that would require a grinder or welder to release it in order to run it. He thinks he'll use it more if it's just waiting in the water - I can relate to that.
