Removing outboard corrosion for repaint

[twright55]

I bought an old, running outboard for pretty cheap.

The only real issue (and probably why it was so cheap) is that it has a really crappy rattle can re-spray over a healthy (or unhealthy, as it were) amount of corrosion.

I don't want to create a beautiful motor...shoulda bought that if that's what I wanted, but:

Anybody have any advice on removing some of the worst corrosion from aluminum and prepping it for paint? I'm not looking for perfection, just something better than what I got.

The only idea I have so far is a wire brush...

[baddjonny]

Don't use a steel brush it will cause even more corosion eg electrolyos between the steel deposited into the aluminum , been there done that it needs to be bead blasted and sanded. the brush will work but the paint job will fail shortly. sorry about the spelling.

jon b

[twright55]

Oh, I didn't think of that!
Great advice...thanks a lot.

I'm looking at the motor a little more closely, and the transom brackets and t&t are really nasty, but the rest of the motor is really not that bad...may not even be original to those transom brackets. It's just been resprayed at some point, most of which is peeling off making it look like sh**.

I've got a can of vinyl zinc chromate primer, and it recommends using paint stripper. I think that's what I'll do. I've got a sandblaster, but not the right media on hand, and I'm afraid of getting sand in all the wrong places...

[Forkin' Crazy]

Glass beading is best, as mentioned, then follow up with etching acid and alodine. Then either zinc chromate or epoxy.

[Jay Smith]

Soda ash, and walnut shell blasting works great and is not as abrasive as some medias are..Then I'd powder coat its seems to be total coverage as its put on with an electrical charge and covers in places spray can't and won't reach...

Good luck,
Jay

[racerx]

Get some limaway soak for awhile and go get some red scuff pads ,and work at it a coulple of times,they sell self etching primer in the spray cans that would work great on it,then spray with some Krylon,if ya just want a quick better look then you have.good luck.

[twright55]

First I hit it with a pressure washer. That removed most of the latest coat of paint. There seems to be about 3 previous coats of paint beneath that!
So then I hit it with glass bead, and it hardly budged the old paint. Ran out long before I made any real headway.

Well, I work for the DOT, and in the lab, they have a bunch of sand that they were going to throw out. I ran it through a sieve and got all the -16 material (my understanding is that most sand blasting material is either -16 or -20.)
I have three types of sand:
Brown sand (not sure what it is, really)
Lime rock
Granite screening

I'm going to experiment with those three. I think I will reserve the granite for steel only (e.g. steering arm) as that stuff is hard and sharp.
Lime rock is really soft, so it might work well on the aluminum. We'll see.
I'm only trying this because it's free ;) As opposed to the $25 worth of glass bead that barely removed 1sqft of paint...

I also ordered a sandblaster that attaches to my pressure washer (about $60) to give that a try.