SODA BLAST / SAND BLAST BOTTOM ....

[THEMOORINGMAN]

Kind of nervous, want to be sure.....

I stripped the bottom of my Edwing last year by sanding and grinding and it worked great! What's left to strip are all the welds were the plates join together, the welded strake to hull joints and some crazy hard to reach spots on the stern.

After failing to hire a soda blaster because it was such a small job for them I bought a sandblasting attachment for my monster power washer and my thoughts were to run baking soda through it so I don't damage the welds. I'm not looking to prep the bottom for paint, i just want 100% of the old bottom paint off and welds undamaged.

Am I nuts? Has anyone done this before? Any blasting do's and don't that I learn from?

[welderbob]

yes Scott, you are nuts. But why should you be different than anybody else? A little sand blasting isn't going to hurt, a lot might. A profiled surface will hold paint better. Hope you have stock in Arm & Hammer.

welderbob

[THEMOORINGMAN]

I'll give the sand man a call then!

I heard Long Island used tons of sand this year on the roads!!! We're getting ice tonight.....joy!! Hay, here's an idea. I'll just trailer the boat up and down the highway to sand blast the bottom.......

[Chaps]

Running baking soda blast media through any wet type system does nothing but make a gooey mess. Its like blasting with cream cheese (don't ask me how I know!)

Get some crushed glass blasting media, fine grade, should siphon into your pw blast nozzle ok.

[THEMOORINGMAN]

Too funny!!! Chaps, you're a Nut too!!!! Doesn't work.....o well.

Did you buy this type or try to suck soda / glass through the soap injector hose that comes with the power washer?

http://www.youtube.com/watch?v=kfA-IkaMRGE

OK, one vote sand and one vote glass.

[Sobie2]

I did exactly what you are suggesting. I got a wet blast attachment and used it with my 3500 psi pressure washer. You do need to buy a lot of what ever type of blast media you are going to use. It does put on a great "toothed surface" to repaint though. I haven't used soda but the fact that it dissolves is what makes it great. Fortunately for me I have a gravel driveway so I just raked the leftovers into my driveway and the mess disappeared.

If you can I think you'd have better results with rented pressure washer of over 4,000 psi. Things may go faster and you may use less media. I didn't damage any welds... didn't even come close.

Sobie2

[THEMOORINGMAN]

So what media did you use? Sand? I think I'm going with Home depot "play sand".

I have a 4000 PSI / 4 GPM unit so I'm hoping it works well. From what I read you really need to be careful not to eat up what you're blasting!!

[Chaps]

You'll need a sandblast kit (siphon nozzle) for the end of your PW gun, a soap sucker won't work. Play sand is too coarse and uneven in texture, find a place that sells graded silica sand if you don't want to track down a better media like crushed glass. Silica sand is dangerous to your lungs if shot dry but in a wet PW set-up it doesn't generate the nasty dust.

[THEMOORINGMAN]

I bought the siphon kit, it's all hooked up and ready to go! My test piece of 6061 plate with bottom paint on it is ready to meet it's match. Hopefully I'm onto something here.

I saw crushed glass at Grainger for $40-$80 per 5 gallon pail......I'll investigate. Glass

You're right about the lungs, I already had my 3m breather and ear protection ready to go! Safety first, cancer LAST!!!

[Chaps]

Find an abrasive blasting supply in your area or google new age glass to find a dealer. You shouldn't have to pay more than about $12 per 50 lb bag

[THEMOORINGMAN]

I spoke with a pure blasting house today and got a lesson....and you're right. Glass seams great. Glass comes in round beads or broken tiny pieces so I need broken. 85 cents a pound. I'm on it like "WelderBob on Aluminum"!!!!

[kmorin]

Another cheap alternative depending on the area, is (white) filter sand. This is white silica that is very soft, usually cheap and used in municipal water filter towers, if your local towns/cities/counties use this type of filter?

Even in rural Alaska I've found it for a few dollars per 50lb, since it is a 'junk' product not regularly used for blasting but is great for wet or dry blasting of aluminum. It will create a decent profile/anchor pattern for coatings, and is deadly to breath in a dry blast application. Not toxic deadly but coating the tubes and lungs deadly. NO paper and string masks for this operation!

I don't think you have to worry much about excessive material removal if you're not focused on one place while you go for coffee?

Blasting is the best for surface prep for paints.

Cheers,
Kevin Morin
Kenai, AK

[THEMOORINGMAN]

Hi Kmorin, great point! For some reason my wife bought me tons of that sand and then hid my 3m Respirator!!