Refurbing outdrive - paint recommendations

[StefanSG]

I posted this in the reader to reader forum but had no recommendations apart from trying in this forum, so here goes...
I am overhauling an AQ100 Volvo outdrive, going to strip it back to bare aluminium , can anyone recommend a diy finish ?
I have been recommended to use an Acid Etch two pack primer, in my previous (google) research a lot of people recommend zinc chromate primer but I understand that is toxic and carcinogenic..
And also recommended, is primer as above, then a hard antifoul (im finishing in Volvo white), something like International Trilux
so anyone got a recommendation for a combination that lasts ? Happy to use International
thanks in advance
StefanSG

 

[BruceK]

If there is anyway you can save the paint that is already on I highly recommend you prep that and overcoat it. I went back to bare metal and etch primers and every year the paint just sloughs off. I even tried what was effectively a gelcoat over them and that also parted ways. I paid over a grand to have them professionally refurbished paintwise by a well respected marine outfit. Whatever Magic-Muti they were originally etched with I have yet to find, or maybe it's just that the porosity of the cast ali absorbs oil and water I have no idea. Nonetheless every year for the last 4 I have had the crowd applaud my beautiful new shiny outdrives in February only to have them looking like plucked duck within 3 months of the season. Dont go there, sharing my pain will bring you no joy.

 

[StefanSG]

If there is anyway you can save the paint that is already on I highly recommend you prep that and overcoat it. I went back to bare metal and etch primers and every year the paint just sloughs off. I even tried what was effectively a gelcoat over them and that also parted ways. I paid over a grand to have them professionally refurbished paintwise by a well respected marine outfit. Whatever Magic-Muti they were originally etched with I have yet to find, or maybe it's just that the porosity of the cast ali absorbs oil and water I have no idea. Nonetheless every year for the last 4 I have had the crowd applaud my beautiful new shiny outdrives in February only to have them looking like plucked duck within 3 months of the season. Dont go there, sharing my pain will bring you no joy.

Hi Bruce what a nightmare. Unfortunately mine are already 50% bare aluminium.

 

[QBhoy]

Hi Stefan…just as Bruce mentions about saving the original paint. I know that often it’s the case that after these things have been anti fouled over the years…it can often look as if you’re through to the aluminium in rough looking patches…but can sometimes actually just be the original paint. Very very similar looking at a glance. Perhaps not the case here…but thought I’d mention.
anyway…sounds like you’re going to do a proper job of it for sure. Personally I’d be tempted to leave the lovely finish, it sounds like you’ll achieve, on show. Hope you don’t mind me saying about the chance you may be actually looking at the original VP paint and not aluminium. Just thought I’d mention. It’s definitely been the case many times, where it’s been mistaken for it.

 

[alt]

Look for a thread I started last year about the same topic. I'm on my phone so harder to search.

1 year later and paint looks like new.

I didn't antifoul, just paint... I'm on fresh water

 

[QBhoy]

Look for a thread I started last year about the same topic. I'm on my phone so harder to search.

1 year later and paint looks like new.

I didn't antifoul, just paint... I'm on fresh water

Will do. Sounds like a great result !

 

[alt]

Found it: Painting DP-G out-drives - back to bare metal - NOT ANTIFOULING

 

[alt]

I should be at the boat tomorrow ill take a pics to show how they are after 1 season

 

[Falcoron]

First things first, if you are going to do this outside or in cold conditions don't! stop now and wait until the weather is drier. Painting below the dew point is never good and no matter how good the prep and paint is it will fail. So unless you have a dew point meter and can control that then you will be wasting your time and money.
If using international go to their site and ask the technical guys for recommendation's, they should be able to do that and send you the TDS ( technical data sheets ) and the HSDS ( Health and safety data sheets ) FOLLOW ALL THESE TO THE LETTER!
Also a great company who specialise in marine coatings is JOTUN, THEY HAVE A HUGE RANGE OF SPECIALIST COATINGS AVAILABLE FOR ALL MARINE ENVIRONMENTS AND BASE METALS.

You mentioned several coatings and stated these were toxic, ALL 2 Pack paint is very toxic and should be treated with the utmost care, ETCH and ANTIFOUL coatings are particularly nasty, and these really require an air fed mask when prepping and painting, but if you follow the data sheets and have the proper PPE there is no risk at all. Read and get to know the hazard signs on the paint labels, you can google these and get a feel for the chemicals you are dealing with.
Epoxy paint will be the best options but ask the paint company of the products or brand you want to use. JOTUN would be my first port of call as they do most ranges that can be applied by brush or roller, as well as sprayable options. SHERWN WILLIAMS in Bolton ( used to be Leigh's Paints now taken over) are also experts in the corrosion protection game and Sherwin are the biggest paint company in the world.

Epoxy coatings have really advanced over the years and can be applied to most substrate's ( the metal or material you are working on) Some are even universal and can be used on almost any surface, so worth seeking out the options from the specialist manufacturers like the companies above.

Aluminium and there alloys are notoriously hard to paint correctly especially in the marine environment. Preparation is key! no mater how good you do this at home it will never be as good as factory. But!! it is doable correctly and will last when you combine the correct paints, techniques and preparation.

I am recently retired from over 40 years in the car, commercial and lastly for 25 years in corrosion protection in manufacturing inc. oil and gas off shore industries.
From what you are saying with the paint falling off and seeing corrosion, ( mainly aluminium oxide salts ) it has already taken hold and this all needs to be cleaned off properly, blasting with the correct medium for the base metal this is the best way but would involve a total strip down of all parts to get it done correctly. Some good blasting companies will do this then spray with the appropriate primer to protect the alloy until you get these painted with intermediate under coats and top coats. Take a bit of time out with a nice scotch and do a bit of research it will save you a ton of time and money if you do.

if you need anything further PM me i will advise as best i can.
Ron

 

[StefanSG]

I should be at the boat tomorrow ill take a pics to show how they are after 1 season

Interested !

 

[alt]

Here's what they looked like after 1 season.... See the other thread for the paint I used and the process of sanding etc...

 

[StefanSG]

Outstanding. So many people mention Etch Primer, I read the International paint guide for sterndrives, they dont mention etch primer, just interprotect (5 coats) on bare metal. But that is impressive, thanks.

StefanSG