white powder?

there are some bubbles under the paint on the old starcraft i bought, along the seams where the bottom meets the sides, chines i think there called...? well anyway, its the same kinda powdery stuff that was bubbleing up on the transom, and there was quite a bit of corrosion on the transom, so i assumed it was some sort of corrosion that made the powdery stuff. but i cant find any corrosion on or in the seams, so what would be causing it? thanks, i dont want to put any money into this boat if there is some unseen corrosion that will make it fold up on me... :shock: :shock: thanks for any info.
ill post some pics of some of the bubbles this afternoon.

hmmmm was the last owner a drug dealer? [-X [-X #-o

could it be from bugs?

OhioStateBuckeye said:

hmmmm was the last owner a drug dealer? [-X [-X #-o

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heh, i knew that was coming.
not sure about bugs, you mean like nesting and laying eggs or something? never though of that.

I would just about bet you that it is galvanic corrosion.

Quackrstackr said:

I would just about bet you that it is galvanic corrosion.

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what exactly is that, and what causes it? sounds terrible....
its the same crap that was bubbling around the steel bolts in the transom, and the transom no looks like swiss cheese. now i REALLY worried...

i think quacker hit it on the head. that does cause a powerdery substance, but dont snort it up your nose. we get alot of motors in with that junk on it that have sat for a long time (usually cars baught from auto auctions). the detailer uses wheel acid (sulferic acid) to clean it off.

deermaster said:

Quackrstackr said:

I would just about bet you that it is galvanic corrosion.

Click to expand...

what exactly is that, and what causes it? sounds terrible....
its the same crap that was bubbling around the steel bolts in the transom, and the transom no looks like swiss cheese. now i REALLY worried...

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https://www.boatus.com/boattech/MarineCorrosion.htm

It doesn't just happen on lower units. It happens on boats when electronics are mounted and a ground is created through the hull, too.

Quackrstackr said:

I would just about bet you that it is galvanic corrosion.

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Concur on that.

You did mention Steel bolts in the transom, and steel and alumunim are not good friends when they're together.

thanks for all the replies so far!

anytime you have , metal, electricity and water, you'll have electrolysis.

what was the electricity coming from? like from a battery or something? i have no idea what was used on this boat before i got it.

OhioStateBuckeye said:

hmmmm was the last owner a drug dealer? [-X [-X #-o

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Great (cop) minds think alike :wink:

It could be oxidation or galvanic corrosion from electrolsis caused by a bad ground.Use stainless steel fasteners and make sure there is no electronic equipment in direct contact with the hull.It's also a good idea to tie up battery cables and wiring.

deermaster said:

what was the electricity coming from? like from a battery or something? i have no idea what was used on this boat before i got it.

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If the boat had a fish finder, trolling motor or electric start, there was prolly a battery involved. I've seen where people have decided to cannect the negative of the battery to their hull and use that as a common ground point for all their electrical needs. This works really well as aluminum is a good conductor and saves them a few dollars on copper wire, which as we all know is getting more and more expensive. Of course the down side to doing that is you are applying current to the hull and where the current leaves the hull and re-enters it is where you will see the corrosion. If there is a battery installed you can check for stray current by connecting one lead of a volt meter to the + battery terminal and the oter to the hull. Reading needs to be 0. Using an ohmeter check from ground wire (disconnected from the battery) to the hull. Reading should be infinite.

:LMFAO: :LMFAO: :LMFAO: :LMFAO: :LMFAO: