Help – Outboard paint disaster

[2hullsonemarinaberth]

My boat has now been out of commission since July, mainly as the result of an outboard repaint disaster.

The short version of the problem is basically that the engineer working on my outboards had to repaint one that had a broken steering arm replaced (different colour), some cover damage, and some paint loss around the waterline. The ouboard was resprayed, and was about to be refitted after a couple standing when suddenly all the paint looked like crazy paving, with cracks everywhere. The engine was again rubbed down, cleaned, resprayed and refitted by the engineer. The boat was relaunched, and within two days the outboard had crazed again.

The engineer has since had some advice that a) its not a paint compatability issue, b) different primer sealers have been used with the same end result, c) that the problem is silicone polish on the outboard which is not removed by a normal rub down with wet and dry and an acetone wash, d) after again rubbing down to bare alloy apparently the primer will not adhere, and the only solution is to sodablast the whole engine, e) that sodablasting leaves dangerous residues that may remain on boat, outboard fittings etc and cause further damage, and f) beadblasting may well damage the leg.

As you can imagine I am pulling my hair out after not having use of the boat since the end of June and urgently need some expert advice as to how to move forward from here.

If I can locate some photos I will add them.

Can somebody who knows about this type of issue please advise?

 

[longjohnsilver]

Why did you stop using yr boat for the best part of the summer, one of the best in living memory, just cos there was some paint crazing on an outboard?
I'd have left it till the winter to sort out. Now winter's here, I'd try cleaning it with acetone, no guarantee it will work, but I can't think of a more effective cleaner.
Good luck with it.

 

[Beyondhelp]

Loads wrong here...

Never seen silicone cause 'crazy paving' silicone causes little dimples in the paint. See here: http://www.mig-welding.co.uk/paint-faults.htm

Are you using a 4K paint system or something else? I have seen this effect happen, but only ever with incompatible paint systems.

 

[itchenseadog]

Sounds like the base coat hasn't cured properly before the top coats have been applied.
What type of paints have been used ?

 

[itchenseadog]

Silicone contamination would result in "fish eyes" not crazing.

 

[beltsandbraces]

will almost certainly not be a silicone issue as this would be apparant as soon as the paint was applied sounds more like the primer/basecoat has not dried fully before the top coat has been applied and has reacted.

 

[RobWales]

My boat has now been out of commission since July, mainly as the result of an outboard repaint disaster.

The short version of the problem is basically that the engineer working on my outboards had to repaint one that had a broken steering arm replaced (different colour), some cover damage, and some paint loss around the waterline. The ouboard was resprayed, and was about to be refitted after a couple standing when suddenly all the paint looked like crazy paving, with cracks everywhere. The engine was again rubbed down, cleaned, resprayed and refitted by the engineer. The boat was relaunched, and within two days the outboard had crazed again.

The engineer has since had some advice that a) its not a paint compatability issue, b) different primer sealers have been used with the same end result, c) that the problem is silicone polish on the outboard which is not removed by a normal rub down with wet and dry and an acetone wash, d) after again rubbing down to bare alloy apparently the primer will not adhere, and the only solution is to sodablast the whole engine, e) that sodablasting leaves dangerous residues that may remain on boat, outboard fittings etc and cause further damage, and f) beadblasting may well damage the leg.

As you can imagine I am pulling my hair out after not having use of the boat since the end of June and urgently need some expert advice as to how to move forward from here.

If I can locate some photos I will add them.

Can somebody who knows about this type of issue please advise?

With such diverse problems, may be worth considering a vinyl wrap!

 

[itchenseadog]

With such diverse problems, may be worth considering a vinyl wrap!

Would tbink too many curves for a vinyl wrap. You need an aluminium etch primer on bare alluminium which needs to be fully cured prior to applying further topcoats

 

[RobWales]

Would tbink too many curves for a vinyl wrap. You need an aluminium etch primer on bare alluminium which needs to be fully cured prior to applying further topcoats

Doub't it has more curves than a Lotus Elise....youtube it..

 

[beltsandbraces]

has more curves than my missus

 

[2hullsonemarinaberth]

has more curves than my missus

Quite happy to check the curves on Belts and Braces missus, but figure that will cause me more issues than the outboard.

The crazing is everywhere, covers, leg and bracket. I am still trying to attach a photo.

The engineer advises me that the outboard was thoroughly cleaned with acetone. He has also painted a test plate and that has not crazed, and the paint supplier has stated that its not a paint compatability issue with the primer, paint and sealers provided (although I'm not convinced).

I was more cocerned about corrosion kicking in rather than just appearance, and having been promised that the second (and then third respray would cure the problem, I gave the engineer the benefit of the doubt (my error). They have now taken the leg off for further testing.

 

[Beyondhelp]

Acetone? Its metal. You would want clean it down with a very strong solvent. 2K paint thinners would do it. Then you want an acid etch primer followed by top coat. That would work fine I'm sure of it.

 

[Beyondhelp]

If you wanted to do a REALLY good job of it. Sand blast the whole thing that needs painting, then get it entirely treated in Alodine and painted. It would have as good protection as if it were new then, if not better...

 

[coreng]

A common cause for crazing defect of marine paints is a high film thickness. Remedy is then a thinner coat of paint, a slower drying solvent and attention paid to the drying conditions.

 

[Vitesse]

Almost sounds like the OP needs a paint person who knows what they are doing.

Sorry - I do know how it gets when you are deep into a problem. Money and time, etc...

 

[VicS]

I have seen this sort of defect several times. On each occasion it was due to incompatibly between coats

There are however other possible reasons.

Coreng mentions excessive film thickness

You will find a list of possible causes at http://pc.dupont.com/dpc/en/US/html/visitor/s/trouble/PDSG_Cracking.html

 

[jimmcgee]

mmm , reaction to paint , needs done cheap enough , will cover almost anything ?? ,:encouragement:

http://en.wikipedia.org/wiki/Enamel_paint

 

[2hullsonemarinaberth]

Trying to attach photo:

 

[Beamishken]

That looks quite a weird reaction unless its a real close up picture usually the crack or wrinkles are closer together

I spent 25 years running a bodyshop & thought id seen every paint fault going but yours does look unusual

in general all the usual suspects for crazing have been covered

incompatible substrates
uncured base layers
too much film build
too short flash off (primer not cured before top coat)
old or out of date hardner in top coat
but it isn't silicone as suggested that gives circular "fish eyes" dots all over

you can get sealer products to isolate base layers from top coats to prevent reactions but we found them to have limited benefit

lots of sanding of the affected areas was the usual answer as the more coats you put on to cover up the problem usually make it worse

over bare aluminium you must use an etch primer

maybe worth posting some better pics with maybe a coin or rule to give some scale

ken

 

[VicS]

That looks quite a weird reaction unless its a real close up picture usually the crack or wrinkles are closer together

Crumbs, yes. I expected to see it broken up into miniature crazy paving