soda blasting questions

[opposedtwin]

I know there have been good discussions before about the soda blasters but I have a couple specific questions. A friend of mine wants to take paint off an older (1977) aluminum canoe and already owns a sand blaster. I told him blasting it with anything other than the soda could heat up the aluminum and possibly cause it to warp. Sooooo…. some questions.

What is the difference between a soda blaster and a sand blaster? Can he simply add soda rather than silica sand to the blaster? If not, could his blaster be modified to work as a soda blaster? Adding a component to the system, etc?

How many cfms @ what psi will be required to get a job of this size accomplished? He has a 20 gallon compressor with a 5 hp motor on it. Seems decent sized but I told him it’s all about the cfms. He’s looking into seeing what his is rated at.

How many bags of soda (I seem to remember 40 lbs being a standard size) of soda do you think he’ll need to remove paint, both inside and out?

Thanks guys!
scott

[SCOTT BOGUE]

Let me see if I can bring something of value here–

1. Having sandblasted aluminum boats before, I do not recommend it because it leaves a very coarse finish, most difficult to smooth if you want a satin or polished final finish. For underneath new paint, perhaps OK. But overheating is not a problem. Maybe with a large, bridge-size blaster, but not with one in a home shop.

2. There are two types of blaster: pressure and siphon. Soda blasters seem to all be of siphon type. Sandblasters can be of either type. I have an old Sears siphon blaster and have successfully used it with both sand and soda.

3. The amount of air needed has everything to do with the nozzle size. He will have to check the required cfm (remember that the psi must also be considered) of the chosen blast gun. Even so, for a small shop-sized blaster, the 5 hp should be fine.

4. Be sure to keep moisture and oil from entering the blast gun. It will mess up the surface he is working on and could cause problems with paint adhesion (again, not a problem if he will be polishing).

5. Sandblasting or soda blasting a large surface uses a LOT of media and takes a LONG time. To remove the paint, I use CitriStrip. It flat works. Around the keel and ribs, and anywhere the rivets are not flush, go with the blast media to get those remaining tiny bits of paint.

auldscott

[wiscoboater]

Scott,
He may be better off farming out a job of that size. It may be a bit to big for the small soda blaster available from Harbor Freight or some other places. Also with that small of a compressor it will be running constantly trying to keep up and will most likely overheat. Google soda blasters in the Madison area. There are a few of them. Most have mobile units and will come to you. A canoe would be about an hours job for them. Using the small compressor and bottle blaster will take a couple days.

[chris-p]

Yeah, before I got my big compressor, I tried a 16′ boat. Took forever! Compressor constantly runs, and you are forever waiting for it to catch up to you. You need a big compressor. Doubt a 120V model would do it. Something that makes over 10 cfm for sure. If not, farm it out as stated. YOu will pull your hair out trying to do it with a small compressor.

[Author]

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