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Aluminium and paint bubbling issues

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RobWarren

Jedi Hopeful
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G'day all

I hope this finds you all in good health and great form.

After 5 months, my car is still being repaired - the paint and panel chap has still not been able to complete the shroud as the paint keeps bubbling and even cracked in one place (by where the bonnet comes down) and he has tried 4 times to get it right and wants to give up.

My insurance assessor is convinced that he's simply not preparing the metal correctly and keeping it clean enough prior to applying whatever solvents/ fillers he needs to.

I know nothing about this and so have sought the opinions of a couple of more experienced Healey owners over here to see if they have some thoughts. Getting a new shroud isn't something I want to do as it's expensive and could take months. Insurance Co. certainly won't pay for it.

The shape of the shroud is excellent post-repair, it's just that the paint wont stop bubbling due to corrosion/ oxidation (apparently).

Any ideas? Does it sound like it can be repaired?

I'd love to hear your thoughts. I really, really miss having Ruby at home and it's almost summer here now!

Rob
 
Hi ROB, as dry as it is in OZ my suggestion is to find another Paint and panel Chap that knows how to Properly clean prime and paint Aluminum.Fwiw--Keoke
 
Hello,

for me it sounds that panelwas not really clean and the primer quality was not for aluminium.
Do you know that the root cause of the crack is not from a mechanical influence ? (micro moving). In combination with wet air the corossion grows....
If you want to do it right, I see only the chance to fix it, if you found the mechanical stress cause and you have to eliminate it.
Than you have to repaint it, on a professional way.
(No chance to do it quick and dirty)

Good luck.

Bye michel- who wait for the next holiday week in Denmark
 
There are chemical conversion processes that will render the bare aluminum inert. This can be easily done on spot repairs, or whole panels.

Just wiping down the bare aluminum panel with "prepsol" or lacquer thinner isn't going to do it.

I'm a big fan of PPG products, though I'm sure you'll find something similar in other paint lineups.

A quick search turned up the following information, not all is applicable, but you get the idea :wink:

https://www.reuters.com/article/pressRelease/idUS235235+02-Apr-2009+BW20090402

https://www.orisonmarketing.com/corrosion/aluminator/aluminator.html?gclid=CKu6r-GfvZ0CFdFL5Qodsho6hQ

https://www.aluminum-rails.com/finishes/kynar.htm
 
Yes, as Randy states, aluminum requires special preparation, with special primers. Bare aluminum oxidizes quickly and will affect paint adhesion. The stuff is self-etching, (sorry don't have a name handy) what the aircraft industry uses to prime aluminum skins of jets.

Surprising if your painter isn't aware of such issues...perhaps good reason to follow Keoke's advice.
 
Thanks guys. At the moment I'm waiting to hear back from the Insurance Assessor as he too is convinced that the areas worked on simply haven't been prepared properly.

If it comes to the crunch I guess we'll have to go to someone else if the current paintshop can't handle it.

Painful, but good to know that there are solutions out there that don't involve spending thousands and waiting months....

Thanks for your input

Rob
 
nevets said:
Yes, as Randy states, aluminum requires special preparation, with special primers. Bare aluminum oxidizes quickly and will affect paint adhesion. The stuff is self-etching, (sorry don't have a name handy) what the aircraft industry uses to prime aluminum skins of jets.

Surprising if your painter isn't aware of such issues...perhaps good reason to follow Keoke's advice.
Click to expand...
Does "zinc chromate" ring a bell?
Patrick
 
Hello RobWarren, you probably won't like my suggestion mainly because it means sending the car to Victoria and I just know that goes against the grain, but here goes.

The man you need to talk to is,

Lach Marshall
CALLANDISH RESTORATIONS
P.O. Box 407
CRESWICK 3363
(03)5345 2940
(04)0061 8050 (mobile)

I have a mate in Melbourne that painted his BN1 himself but after a while the paint chipped and fell off in sizeable pieces. He had to have it all done again and this is who he took it to.

germanmichel, I believe the crack being referred to is in the paint not in the aluminum.

Best regards,

bundyrum.
 
Hello @ all,

ok, metall internal corrosion is possible. But remember for any kind of corrosion oxygen and a fluid to start the chemical process has been available.
Practically : Directly after grinding aluminium has to be primed (to prevent aluminium oxid)
Also it have to worked with very clean tools that no iron particles can contaminate the aluminium, the particels works silent under the paint...
Anyway,in my experience, the root cause of cracks in the paint,is mostly a mechanical stress on excessive strong paint, to much bondo thickness or everything else.
After than, the door is open for any kind of corossion.
If we can see a detail picture, I think the answers will be more correctly. Everything else is a view in a glass ball...

Bye michel- my language mistakes are only to have fun for natural speakers..
grin.gif
 
Michael Oritt said:
There's nothing new to painting aluminum--they've been doing it to planes and boats with intended use to be in pretty harsh environments for quite a while now.

It's all in proper surface preparation and coatings application and following instructions. For one product that has been used with some success check out the Awlgrip site: [url=ttp://www.awlgrip.com/Pages/home.asp.][url=ttp://www.awlgrip.com/Pages/home.asp.]ttp://www.awlgrip.com/Pages/home.asp.[/url][/url]
Click to expand...
I couldn't get your links to work, but I'm guessing this is a useful page from that site: https://www.awlgrip.com/products/search/pages/Alumiprep_33.aspx
 
"I couldn't get your links to work, but I'm guessing this is a useful page from that site: https://www.awlgrip.com/products/search/pages/Alumiprep_33.aspx"
---------------------------
Randy--

Yes, it is part of the system. My boat, which I sold a few years ago, had lots of aluminum spars, stantions, hardware, etc, almost all fastened with SS screws and bolts, etc. all of which created potential for corrosion and electrolysis. The worst situation is where there is actual movement between the materials and mechanical isolation (bushings, sealant, etc) is helpful But just using paint on aluminum, wood, steel, etc. in wet, cold, high-elevation, sub-surface salty environs puts coatings to incredible tests--way more than what we will ever experience on our cars.

There are or were used to be other brands--Sterling seemed to be the product of choice for the trucking industry whereas Awlgrip came out of aviation and ultimately dominated marine.

I had good experiences with Awlgrip when instructions were followed and incredibly bad ones when a step (a wash, rinse, etc) was missed.
 
Michael Oritt said:
"I couldn't get your links to work, but I'm guessing this is a useful page from that site: https://www.awlgrip.com/products/search/pages/Alumiprep_33.aspx"
---------------------------
Randy--

... I had good experiences with (name <span style="font-style: italic">any</span> product) when instructions were followed and incredibly bad ones when a step (a wash, rinse, etc) was missed.
Click to expand...
Yes, funny how that is, and perhaps what's happened to poor Rob's car.
 
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