Outdrive corrosion repair

[depasseg]

My volvo penta outdrives are in need of a little TLC. There's a decent amount of corrosion that could use some media blasting, aluminum prep/etch/primer and 2-part epoxy painting.

Does anyone in the area do this?

[Rich]

A couple of years ago I took my drives to a local shop here in the southern NH area. They specialize in media blasting and to meticulous antique blasting, so I knew they would be gentle on my drives. They use crushed glass as a media.

http://www.classiccarblasting.com/

I then primed and painted them myself, purchased new decals and they came out looking like new!

I'm sure you could find someone to repaint them if you had them blasted, this is just an idea for you.

Just realize that you have to be very careful of all the seals, and internals, you may even want to have the oil changed after you're done refinishing, just to be sure no blast media gets inside to mess things up.

[Broken Glass]

After you get your drives re-painted, consider changing all of your anodes to Magnesium instead of Zinc. Magnesium anodes are more effective than Zinc in fresh water. I have used both and I can attest to the marked difference resulting in less corrosion when Magnesium is installed.
Thanks
Dan

[Rich]

Dan makes a good point! Boats on the lake should have Magnesium anodes.

[Dave R]

If the drive is pitted, you can spend a little quality time with large quantities of JB weld to fill the pits (like Bondo) after you get down to bare metal. Works great and will look like new after sanding and painting.

I agree with everyone else on the advice to use magnesium anodes. Get in the water with a stainless steel wire brush and clean them up now and then too, once they get a coating of corrosion, they become much less effective.

[SAB1]

Rich how has it held up? i looked into this a couple years ago as well and was told it would only be a temporary repair and the problem would come back so I dint bother spending the money. Would like to fix though if it will hold up.

[Rich]

Mine held up pretty well.

I followed the Volvo approved procedure, it required buying some special chemicals to prep the aluminum.

I did have a small problem, which was my own fault, that may have affected the lifespan of the job.

My boat launch was coming up, and at the time we had some cool rainy weather. I got a two day window of good weather and decided to do the painting.

My problem was that I did a few coats of each layer, 2 primer coats and two top coats in two days.

I didn't leave the primer coats enough time to dry, considering the temperatures, so I ended up with some pimples under my topcoat after some time. I think this was because the primer wasn't completely dry when the top coat went on, due to putting on two primer coats in one day (even though I followed the directions on the paint, I think I would have been better off waiting for more time between coats considering the temperature).

Other than this, and the apparent issues of these 'pimples', it worked well.

So don't rush, give yourself plenty of time!

In the end, my IOs look much better than if I had left them alone.

One thing that I couldn't do, was the transom rings and mounts, as these were still on the boat, and I wasn't about to remove those.

I think my IOs were a bit corroded due to the previous owner leaving Zinc anodes on them for years, of course I now switched to Magnesium.

Since I did all the work myself (other than the media blasting, and I paid the mechanic to remove and reinstall the drives), I was only out the cost of the paint and decals, so it wasn't too expensive.

I'd do it again myself, just giving more time for the painting. If my garage wasn't full of things, if I had done the painting indoors, I wouldn't have had the paint drying issues IMHO.

[HellRaZoR004]

Rich - do you recall how much they charged to blast your drives? Thanks!

I removed my Bravo 3's in the fall and I'm in the process of cleaning / sanding them down. Would be a lot easier to drop them off if the price is reasonable.

Will it warm up already!

[ITD]

Originally Posted by Broken Glass

After you get your drives re-painted, consider changing all of your anodes to Magnesium instead of Zinc. Magnesium anodes are more effective than Zinc in fresh water. I have used both and I can attest to the marked difference resulting in less corrosion when Magnesium is installed.
Thanks
Dan

This, same experience here. Check them each year, mine were just replaced again this year.

[Rich]

Originally Posted by HellRaZoR004

Rich - do you recall how much they charged to blast your drives? Thanks!

I removed my Bravo 3's in the fall and I'm in the process of cleaning / sanding them down. Would be a lot easier to drop them off if the price is reasonable.

Will it warm up already!

In 2014 it cost me $200 for two IO drives.

At first I thought I could do this myself, cleaning, sanding, brushing, etc.

For the amount of work I had ahead of me, and considering their results, I would have been happy to pay three times this price!

After the blasting, the drives were extremely clean and ready to be primed, I almost hated to even get finger prints on them, they looked that clean.

It's a steal of a price for the work they do for you.

I prepped the drives, removed all the decals, masked off areas where I didn't want them to blast (mating surfaces, bearings seals, shafts, etc.).

I added the before and after photos below.

The drives looked brand new after I was done. Of course the pimples didn't show up until about a week later. LOL

After being in the lake water for a year or more now, they don't look as shiny and new as they did the day when I completed them, but I'm glad I did this work, and would do it again.

[HellRaZoR004]

Thank you!

[Rich]

You're welcome! If you go to the same media blasting company, let them know that I referred you.

I think they said that I was the first set of IO drives that they had done at the time. They did a great job!

It's a small shop owned by a husband and a wife. The wife does the media blasting, you get a gentle touch!