Bottom Preparation

[Fortunate]

After 24 years, the bottom paint build up on Fortunate is getting bad. I am thinking of stripping the existing paint and starting fresh with a new coating system.

Any thoughts on the best way to strip bottom paint and what system is prefered after stripping? I have talked to a few people about soda or walnut blasting. The soda seems to be very corrosive, not sure on the walnut shells. Has anyone tried either method?

[rt11002003]

Kim,

Any pressure blasting will erode the surface where the materials hit. In all likelihood removing the bottom paint by blasting will also damage the gelcoat, ie. erode it. In my area, bottom paint is removed by scraping and sanding.

To the best of my knowledge soda, walnut shell and bead blasting are used to remove both the bottom paint and the gelcoat when preparing to repair extensive blistering. Perhaps a really talented person could remove paint without hurting the gelcoat.

If the gelcoat is damaged (eroded or otherwise) a good barrier coat such as Interlux is applied (multiple coats), the surface sanded until it is fair and then bottom paint applied.

By the way we used to clean jet engine compressors by dumping walnut shells into the inlet duct with engine running. We also had problems with high pressure fuel eroding parts in the fuel controls.

Gene

[Veebyes2]

Anyone tried soda blasting? I don't mind doing the annual water blasting & repainting myself. Taking it right back to gel coat is best done with a credit card. I don't have the equipment or skills to do that without risk of serious damage.

[tranmkp]

It did a good job, but it was not perfect - some paint stayed - you will still need to sand down to the gelcoat - apply the hibuild sealer/epoxy, then the bottom of your choice. I have had good results with VC ofshore and Petite Vivid -

Of note - if you can swing it have the bottom sprayed - then have your prop scanned -

The results will be staggering - trust me.

Vivid is ablative and VC offshore - is a hard teflon - very thin - easy to spay and recoat.

[rt11002003]

The current issue of "PassageMaker" has an article on using soda.

Gene

[Fortunate]

What exactly will prop scanning do for my little Albin and how much does is cost?

Did you find the soda blasting to be corrosive to any of the surrounding metal items, ie, stands, appurtances, etc?

[tranmkp]

Its a system out there that some shops use - its another way of blue printing your prop. It cost a couple of hundred bucks to do mine. The old prop and tons of barns on it - I cleaned it off, tested it and it felt great, the next week I pulled it and sent it to the shop and also paid a little more and had it polished. I have a new driveline (stock, no aquadrive or miracle shaft setup, although it would really be nice) the difference with just the clean prop vrs the reconditioned on was ( Im thinking KY jelly here) very slippery, I dont think I go anymore top speed but the boat did seem to really respond to throttle. If you have the correct pitch for you engine gearbox setup and you r shaft is aligned, bottom really clean - thats about all you can do for these little albins. Like one guy told me, it you put in a smaller engine 27-35hp and change the prop and not worry about 12knts and be happy with 7 or 8 knts you would see a big difference in fuel consumption.

My yard used soda to minimise antifouling sanding... more of a envior req.

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[pred36]

Just had the bottom soda blaster on our 1980 classic. The soda blasting isnot as agressive as the sand blasting. We are in the process of sanding off the balance of the old barrier coat now. I would recommend sand blasting only if you want to minimize your sanding. Both can be done enviromentally friendly by tenting the bottom well.