Paint Peeling Problems :(

[Theo]

When Margaret painted Theodora in 2008 she covered up the old all over maroon job.  I was commissioned with keying up the surface and, since the maroon was in good condition this I did.  Only spot treating the very few rust spots.  Ten years later Theodora was still looking presentable but tired so we decided to get a proffessional paint jobe done.  Margaret didn't want to do the bulk of the boring bit of painting but decided to do the fancy bits herself.  So we asked the painters to leave the gas locker hatch and its surrounding deck, along with the top bends just undercoated.  The cabin slide was left with the raddle coat that was used for the roof.

 

She painted the bits mentioned.  The photos show how the paint is pealing of.  In fact you can rub it off with your fingers.  What is the most likely explanation?

 

 

[Higgs]

Poor prepping. Not enough keying, or there is contamination. 

 

 

[Dav and Pen]

Could be a reaction between different makes or types of paint.

 

[Barneyp]

If it's coming of easily in lots of different places then the top coat has clearly not bonded to the undercoat. From what you say the was professionally prepped, undercoated, and then most of it top coated. Leaving the Margaret to paint the remaining undercoated areas (the fancy bits)

I'm guessing by the time you got the boat back from the painters the undercoat would have fully cured, so would have needed sanding all over to create a key, I think lack of or insufficient key is the most likely explanation.

It could be contamination, but that seem unlikely as it is all over the bits you painted.

Possibly different types of paint, but I'm guessing as you painted the whole boat before you have some understanding of paint types, also if there was a key most paint would stick better than that.

[Theo]

Thanks for the ideas.  Keying is favourite in my mind (mea culpa).

 

I will do some experimenting and assess the results.  The peeling happened relatively quickly so I should know reasonably soon.  The later experience is very different from the early.

 

N

[Chewbacka]

It’s also possible the boat yard gloss was polished, or even another boat near by was polished or even ‘dirty’ rain left a residue on the primer surface, so not only does the primer need a rub down, but a good wash with sugar soap as well.  Did it get a good wash before painting?