what went wrong with my outdrive?

[newtoboat101]

 

[newtoboat101]

during winter i re painted my upper outdrive,put boat in my slip on lake ontario ,when i pulled out last week after being in water all summer ,my upper unit looked like this all paint gone ,,whats going on here ,i used merc outdrive primer and paint on upper unit and skeg,, felt outdrive paint would be fine ,also i added a mercathode over winter ,if that means anything, this is paint i used

Mercury/Quicksilver Parts Paint Phantom Black 92-802878Q 1​

 

[alldodge]

Unable to see any pic
Might be an issue with your mercathode

 

[newtoboat101]

thank you for letting me know pic is not there

 

[newtoboat101]

here's pic

 

[crazy charlie]

during winter i re painted my upper outdrive,put boat in my slip on lake ontario ,when i pulled out last week after being in water all summer ,my upper unit looked like this all paint gone ,,whats going on here ,i used merc outdrive primer and paint on upper unit and skeg,, felt outdrive paint would be fine ,also i added a mercathode over winter ,if that means anything, this is paint i used

Mercury/Quicksilver Parts Paint Phantom Black 92-802878Q 1​

What type of coating was already on the upper?? Did you sand and prep for painting?? Paint will peel when applied to a surface that is not properly prepared for painting including temp of the paint,surface to be painted and ambient temp etc.Charlie

 

[Lou C]

looks like you need anti fouling paint

 

[poconojoe]

Darn, that's terrible!
Seems the primer and paint didn't adhere to the metal properly.
Aluminum can be a bit temperamental. Maybe there was some oxidation on the metal right before you painted it. Aluminum can oxidize pretty quickly. But I'm by far no expert. Just guessing here.
Could it have anything to do with it being an SEI and not a Mercruiser drive? Aluminum is aluminum, so I wouldn't think that would matter.
Awaiting for the experts to chime in...

 

[76SeaRay]

It appears the lower unit is fine, just the painted upper unit. I would think that if it were electrolysis due to problems with the mercathode, the lower unit would be impacted as well. Looks like a paint problem to me. What type of primer did you use? As others mentioned already, did you sand and then clean before primer? Did you sand the primer if it was allowed to completely cure or dry? What temperature did you spray the paint? Did you spray a light flash coat before the final coat on the primer and the topcoat?

 

[newtoboat101]

when i got the sei ,the upper chipped ,real easy so it had chips in it ,so i sanded upper,didnt sand down to metal ,but did sand very rough, then i put primer paint thats the match for paint i was using ,really amazed at how the original paints even gone ,no flakes ,just all gone , but the lower is fine

 

[crazy charlie]

Darn, that's terrible!

Could it have anything to do with it being an SEI and not a Mercruiser drive? Aluminum is aluminum, so I wouldn't think that would matter.
Awaiting for the experts to chime in...

I thought SEI was plastic or composite and not aluminum..?? Charlie

 

[newtoboat101]

all valid questions, temp was around 60 degrees when primer and paint,and i forgot to mention i put clear coat on it ,looking for pic

 

[76SeaRay]

Hmm, maybe you needed a seal coat over the sanded old paint before painting with primer. That is typically done unless the primer is rated as a seal coat. Might be an interaction between the old paint the new primer. Primer needs to be compatible with the substrate as well as the finish coat. I would suggest taking it to bare aluminum and then do proper aluminum prep and cleaning followed by an epoxy primer and suitable topcoat. I have never used the Mercruiser Phantom black so others need to weigh in on how to fix the problem properly with that paint.

 

[newtoboat101]

fresh paint pic

 

[76SeaRay]

Temp sounds a little low... That is generally the low end of acceptable paint temp ranges for most paints but check the specs.. As I mentioned, I haven't used the Merc paint but it should be similar to other paints. Do you have the Merc procedure for painting a drive with their paint?

 

[76SeaRay]

Usually, clear coat will flake off the topcoat if not painted correctly or not compatible (see old cars - its called sunburn on them).

 

[newtoboat101]

thanx for replies ,i guess we can assume that its not a mercathode,,electrosis or anything like that ,and just bad paint job or paint used ,or maybe temp ,nothing crazy ,correct

 

[76SeaRay]

That would be my guess but others with experience with the mercathode would be a better judge.

 

[alldodge]

thanx for replies ,i guess we can assume that its not a mercathode,,electrosis or anything like that ,and just bad paint job or paint used ,or maybe temp ,nothing crazy ,correct

Only way to know is repaint. Then with boat back at the dock plugged in for at least 24 hours and measure the output voltage with the correct probe.

Right now it does look like a bad paint job. Next season watch the drive to see if it starts again

 

[Scott Danforth]

to get paint to stick to aluminum

the aluminum surface must be rough enough for a mechanical bond. tis is usually blasting or sanding
the aluminum surface must be chemically cleaned and etched to remove oxidation. usually an acid wash
an etching aluminum primer must be used (this is a 2-part primer)
then an epoxy sealing primer (this is a 2-part primer)
then a top coat