painting saildrive legs

[velella15]

What paint can be used on saildrives? Antifouling paints can be used on a FRG hull but paints containing copper or tin cannot be used on saildrive legs because of electrolysis between dissimilar metals. I could use a 2-part polyurethane or epoxy - these would protect but have no antifouling properties. What do others do?

[SVNeko]

Take to bare metal, epoxy barrier coat, 3 coats antifoul for aluminum (Trilux). Be sure not to coat the area where the anodes make contact with the leg.

Take a look at Sail Drives

[poppyduc]

Originally Posted by velella15

What paint can be used on saildrives? Antifouling paints can be used on a FRG hull but paints containing copper or tin cannot be used on saildrive legs because of electrolysis between dissimilar metals. I could use a 2-part polyurethane or epoxy - these would protect but have no antifouling properties. What do others do?

For the past 6 years have on our SD20 sail drive have painted with Propspeed preparation. Done yearly maybe done a little to often but always looks like a new unit and clean as.

[fstbttms]

Originally Posted by velella15

Antifouling paints can be used on a FRG hull but paints containing copper or tin cannot be used on saildrive legs because of electrolysis between dissimilar metals.

Dissimilar metals in contact with each other while immersed in a electrolyte causes galvanic corrosion, not electrolysis. FYI.

[Captain Bill]

Originally Posted by velella15

What paint can be used on saildrives? Antifouling paints can be used on a FRG hull but paints containing copper or tin cannot be used on saildrive legs because of electrolysis between dissimilar metals. I could use a 2-part polyurethane or epoxy - these would protect but have no antifouling properties. What do others do?

I lightly sanded my new sd60 saildrives, put on a coat of Pettit Tie Coat Primer and then put on three coats of Pettit Ultima Eco. It's been on for only 8 months, but after spending two months in the Indian river, the entire bottom was heavily covered with growth that was hard to scrub off, except for the saildrives which were just about as white as the day they were painted. The props were pretty heavily coated with barnacles and the rubber sail drive boots and the spots on the keels where it had been blocked had 3/4 inch barnacles. There was absolutely nothing on the saildrives. I don't know how long it will last as it is advertised as a multi-season ablative, but so far I'm happy with it.

[Privilege]

I did a lot of research on this recently prior to painting my new saildrive lower legs. The consensus is that a few coats of epoxy barrier coat is a must. Some schools of thought say that the leg can then be painted with a normal copper-based anti-fouling and people who have done this have reported no ill-effects, the thinking is that as long as the copper based paint does not come into contact with the aluminum leg then there will be no corrosion. However, erring on the side of caution and not wanting to ruin an expensive drive, I went with the other school of thought which advocates using Trilux 33 anti-fouling which is designed for aluminum and can be applied in thick coats, unlike the aluminum anti-fouling that you buy in spray cans.

[Captain Bill]

Originally Posted by Privilege

I did a lot of research on this recently prior to painting my new saildrive lower legs. The consensus is that a few coats of epoxy barrier coat is a must. Some schools of thought say that the leg can then be painted with a normal copper-based anti-fouling and people who have done this have reported no ill-effects, the thinking is that as long as the copper based paint does not come into contact with the aluminum leg then there will be no corrosion. However, erring on the side of caution and not wanting to ruin an expensive drive, I went with the other school of thought which advocates using Trilux 33 anti-fouling which is designed for aluminum and can be applied in thick coats, unlike the aluminum anti-fouling that you buy in spray cans.

I used Trilux once about 9 years ago over the prescribed zinc chromate primer. The only place it didn't grow barnacles was on the spots that peeled off. It seems that the zinc chromate primer made pretty good anti fouling.