Sandblasting aluminum boat

[Farley]

I heard this warps the aluminum unless you use walnut shells or something, is it true?

[musky hunter]

Using a hard grit media such as garnet would indeed do bad things to the aluminum. Among others, it would leave a rough surface profile open to more oxidation and water resistance. There is also the possiblilty of warpage as surface stresses can indeed become unbalanced in a grit blast application. Furthermore, if the nozzle is left too long in one spot it would literally abrade a hole through your hull.

But blasting with walnut shells or corn cob media would be a much wiser selection of media because they are soft and not likely to damage the aluminum substrate.

You might have to search to find this media if you are doing it yourself, but any commercial blast booth would have access to it if you are going to pay to have it blasted.

[Farley]

Thanks Muskyhunter, I've heard baking soda works well too.

What about paint, what kind of paint will last on a boat\trailer? Polyurethane?

[IFallsRon]

There used to be a place in St. Cloud that advertised a pressure washer with cleaning soda on boats and airplanes. I called one time and they said they'd do a 16-foot boat for around $100. The place closed but you can probably get cleaning soda at a place like Grainger.

[Farley]

Would it damage a pressure washer if you put baking soda in it along with the water?

[IFallsRon]

It seems to be a normal operation. That's what they use to clean buildings and headstones.

[Farley]

Cool, thanks!

I guess I should have asked this before but if I mixed baking soda and water in a pressure washer, would it be enough to get the paint off and also score it enough to where the new paint will stick? Sorry for all the ?'s.

[magnumthunder]

U do not want to run soda though the washer it will chew the seals right out. there is a special hopper for this kinda like sand blasting. I just used silca sand with an attachment for the pressurewasher. the boat I did was for duck hunting and it work fine FOR ME! There was some other more course sand but like they said above it can rip a hole right though it. Ps I turn the washer down to about 2000 psi. and didnt work to close. It does leave the surface rough but it holds the paint well. Just my 2 cents! ‹(•¿•)›

[DrKen]

Another option to remove the paint is to use a aircraft type stripper. This is made for aluminum, just follow instructions and then use a acid wash to etch before priming and painting.

[IFallsRon]

Baking soda is made from soda ash and is slightly alkaline (ph 8.1). Washing soda is sodium carbonate and has a ph of 11. It's caustic and will remove about anything.

[Steve Bakken]

Alumacraft is currently in the proccess of stripping and painting several hundred boats under warranty due to some paint issues. They've experimented with numerous methods of paint removal. The soda blasting works well to get it off, but cleanup prior to painting is crucial. They've had several that couldn't get the paint to stay in the seams around the keel and transom after blasting because the residual soda repelled the new paint. Chemical stripping works well, but it's messy, and again, cleanup is crucial for the same reasons as soda. When we strip customers' boats, oftentimes we use the chemical stripper. It's much less invasive to the metal. But the metal still has to be prepped for paint with a sander and 180 grit .We've experimented with many methods and we've found that good old manual labor with a dual action sander has also been cost-effective for the customer. Much of the decision depends on the type and condition of the paint. With the D.A., 80 grit, followed by 180 and it's ready for paint. Much less extensive cleanup. As for your question about paint, most any paint will "stick" but you'll find, just as with anything else, you get out what you put into it. An acid-etch primer is highly recommended. This should be followed with a good 2 part sealer. Direct gloss paint will work but it will fade in time. The best top coat to use is a basecoat that gets a clearcoat over the top of it. Now you're talking automotive quality and it will last as long as your boat does. Also, don't mix and match brands of products. Products within the same brand are designed to work with each other and will give you a much better peace of mind. There's nothing worse than going to all that work and then having one layer start peeling away from another layer because two brands weren't compatible.