paint bubbles and corrosion

[timddo]

Ok.

My boat is approaching 2.5 years or so and i'm seeing signs of paint bubbling.
Repairing is a pain and it will bubble soon after.

The Main problem is the False floors. The darn floors are screwed down. A screw will make contact regardless if you put duralac or not. Any solutions to this. Why don't they make aluminium screws????????


If anyone knows the colour code for brillent white. pm me.

Tim

[Noelm]

I guess paint bubbles are a fact of life for most alloy boats, kind of like rot in a glass boat, but with good preperation (something not often found in mass production) and care it is minimised, aluminium screws would be way too weak, they are available as are aluminium bolts, but even with the same metals bolted/screwed/riveted together in salt water, corrosion almost always takes place at some time.

[bigjimg]

Well you could drill and tap the hole and use a threaded screw with lano applied or put in a nylon insert after drilling to suit or use a rivet nut in stainless set in with duralac applied.Lots of choice but stainless is the way to go.As with the bubbles goes hand in hand with painted ally.Sand it off the top decks and just use clear.Jim

[Seahorse]

just shit primer. my stacer is 3 yrs old and same thing.
i will sand mine back and etch prime properly, then recoat. cant see clear doing anything.
i would think corrossion comes from beneath.

[black runner]

Must be luck of the draw. My Stacer is 6 years old and there are only 2 spots where bubbling has occurred and both are near stainless screws which have no Sika or duralac rest of the hull is as good as gold. Sand back, etch prime and touch up.

As far as the floor goes, a good squirt of Sika into the hole in the floor before the screw goes in will minimise salt water getting to the ally. If you want to get really tricky while the floor is out put a finger full on the underside of the floor support where the screw will protrude. Make sure the screws protrude no more than 10mm and the Sika will encapsulate the underside too. Will need to redo each year when the floor is pulled though.

Cheers

[haggis]

yeah my ally craft is doing the same thing , pulled up all the screws & put plenty of durolock on them to see if that helps , no sign of any durolock getting done at the factory or by the dealers who fitted out the boat . still love my boat .
cheers jimmy

[White Pointer]

G'day,

There seems to be lots going on here that is defying your maintenance efforts.

What is the boat and what are the floor plates?

Regards,

White Pointer

[Gippslander]

I have the same problem on my Quinney. I have just had a second battery installed and the Autolec has earthed everything from the batteries. Previously everything was earthed back to the body of the boat. Should stop 90% of the electrolysis.

[black runner]

I have the same problem on my Quinney. I have just had a second battery installed and the Autolec has earthed everything from the batteries. Previously everything was earthed back to the body of the boat. Should stop 90% of the electrolysis.

Sorry to squash your theory Gippslander but the -ve terminal of the battery is connected to the outboard which is in turn bolted to the hull. The negative side of the circuit is therefore bonded to the hull (also via steering and shift cables). However as with the previous bonding plate you describe, the hull in either instance is not being used as an automotive style -ve return circuit. The only time you would get appliance current flowing through the hull is if someone has incorrectly grounded a -ve from an appliance/accessory to a part of the hull structure rather than a bus bar that would be connected to the bonding plate and battery -ve.

Cheers