I agree with Bill, in that you may want to think of a commercial blaster. You could also rent the pressure pot and associated equipment. You don't need the largest units made but bigger than what harbor freight sells.
However, I would not use sand to blast 0.058" aluminum. If you do, there won't be any metal to put new paint onto. I would use something like baking soda, that works very well for soft surfaces and machined parts. But even with that it is possible to make holes if you are not careful and keep the nozzle moving.
Side point: Some cereal packaging factories have used Wheaties, Cheerios, etc, because sand or grit would contaminate food product. And it worked. But I wouldn't make a run on the supermarket to buy up all their cereal. Check with a reliable paint supply store for recommendations, costs, and availability of suitable products.
Chet Guilford
I agree with Chet that's not adviceable to sandblast an aluminum plate 0.058 inches thick. Aluminum is softer than steel and sandblasting, if not carefully supervised, can erode the metal down to dangerous levels.
Regarding silica and sand, their chemical formula is the same (silicon dioxide), as is their hardness (7 in the Mohs scale). The difference is that silica can be bought in finer grain size than sand, and so the blasting can be better controlled. But, if as Chet says, even baking soda can make holes in the aluminum, silica would surely make larger ones.
Why don't you try organic paint solvents (removers), or rubbing the painted surface with steel brushes?
Giovanni S. Crisi
Sao Paulo - Brazil
I am trying to remove bottom pain from the boat. I have tried four diferent chemical cleaners to do this with no luck. Since I do not know the type of paint, I am just fishing with respect to a chemical to remove the paint. Several people have told me they have had luck with sandblasting the aluminum on these applications. They have told me to practice on a beer can removing the paint.
After the paint is removed, I need to etch the aluminum then put an epoxy paint on it so it will be stronger.
Thanks for the help so far.
Good idea to practice on a beer can. Practice as long as you need until you feel confident that the actual work on the boat will be successful.
Giovanni S. Crisi
The beer can made me think of 3M Roloc Abrasive bristle discs.
They impregnated the rubber bristles with various grits and these things are awsome!
We first discoverd these things being used for epoxy graphite
composit flight control surface repairs. The same disc will hog fully set epoxy from a
putty knife or take the paint off a coke
can. The soft bristles will conform to the shape of many objects.
They last much longer than I thought they would and leave little residue.
http://products3.3m.com/catalog/us/en001/electronics_mfg/esm/node_K9RNN39414be/root_GST1T4S9TCgv/vroot_DPB1Q1MJ7Nge/gvel_2B4W8PPJ9Xgl/command_AbcPageHandler/theme_us_electronicsesm_3_0
I have been trying to bottom feed on ebay to get my hands on a couple of these. Ill let you know. Thanks for the suggestion.
use crushed walnut to strip the aluminum, it wil strip the paint with out marring the surface. Then use alidine "aluma prep " to ech the surface then an epoxy primer sealer such as DPLF 40 from PPG. If you don't etch the aluminum you can get a primer rich in zinc which will still etch the surface and give you a surface the will permit paint to stick...Epoxys work the best with catalized top coats...
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