Stripping paint by Soda Blasting?

[Markus33]

Has anyone heard of / tried this method described below of using Sodium Bicarbonate powder remove paint?

Copied from a company called ProBlast website but I've found several companies that do this.
http://www.problastusa.com/soda_blasting.htm

Soda (sodium bicarbonate) - "Soda Blasting Products"

SODA BLASTING APPLICATIONS Auto Restoration Industrial

"What is Soda Blasting?"
Soda blasting is an environmentally friendly way of removing paint, dirt, coatings, and other surface contaminants that will not cause damage to the surfaces being cleaned.

Soda blasting is a non-abrasive action. The action of sodium bicarbonate will not cause heat build up, sparks, or abrasion to the surface being cleaned.

Soda blasting was developed by New York State engineers looking for ways to clean and restore the Statue of Liberty. They had many concerns involving issues of the environment, waste disposal, and protection of the Statue of Liberty itself. Use of any abrasive material to clean the surface would have been harmful to the soft copper plates. Used blast media waste in the surrounding water was also a concern. Soda blasting was created because it would not only do the job while having a minimal impact on the waterways and harbor but it was also non-abrasive.

Soda Blasting - Soda Specs
"How does soda blasting work and what are its advantages?"
The sodium bicarbonate used in the blasting process is a larger particle than the baking soda used in the food industry, although it is the same purity. The particles (baking soda) are propelled by compressed air through specialized blasting pots. The blasting pots use air pressure that can be varied from 20psi on soft surfaces to 120psi on harder surfaces. The now pressurized sodium bicarbonate particles remove coatings by the energy released when the particles explode as they contact the surface being cleaned.

Sand blasting, on the other hand, removes the coatings by wearing it away (abrasively). This is also the result when the sand hits the base surface being cleaned; the base surface is worn away and damaged. Sodium bicarbonate has a non-abrasive action that allows it to be used on surfaces that the currently popular abrasive media (sand blasting) would damage i.e.: aluminum, stainless steel, brick, stone, glass, fiberglass, wood, plastic, seals, bearings, splines, radiator cores, and hydraulic cylinders. Since there is no heat build up warped metal is eliminated. The non-flammable properties allow sodium bicarbonate to be used in the petroleum industry where other methods posed a higher risk. Sodium bicarbonate breaks down hydrocarbons, which makes soda blasting an excellent method of cleaning engines, engine parts, and other areas where oil and grease are present.

Another major advantage of soda blasting is that it does not break down the surface tension of metals, thus the problem of flash rusting is eliminated. Sodium bicarbonate can act as a rust inhibitor, which will leave a protective coating on the surface being cleaned. This allows for time to pass before the surface has to be painted. This is unlike a sand blasted surface that must be painted immediately. When the time arrives to paint the surface, the protective coating (soda) can be removed by an application of a vinegar/water mixture.

"What about clean up and disposal?"
Sodium bicarbonate has a pH of 8.4 and can be disposed of in most wastewater treatment systems. The only material that needs to be disposed of are the coatings removed, which can be separated by dissolving the blast media in water and the use of a filter or centrifuge to separate the coatings from the now dissolved soda. Disposal regulations should always be followed as this will vary depending on the coatings being removed. Normally only the hazardous materials that are removed need to be disposed of in special areas. Sodium bicarbonate can be neutralized by either a vinegar/water solution or just water dilution.

Regards,

Markus

[304065]

We know all about it. I started a business in 1992 that did exactly this. It works very well. Dry blasting raises more dust but cuts faster.

[KevinP73]

Originally posted by john_cramer
We know all about it. I started a business in 1992 that did exactly this. It works very well. Dry blasting raises more dust but cuts faster.

Isn't it also biodegradable? How does it do with the harder stuff like rust and heavy built up and dried on grunge?

[Markus33]

What about this claim:

-Sodium bicarbonate can act as a rust inhibitor, which will leave a protective coating on the surface being cleaned.

What if the sodium bicarbonate is not completely removed from seams, etc. Won't the sodium (salt) part cause corrosion?

Thanks,

Markus

[304065]

I wouldn't put much stock in the "rust inhibitor" part of it. Maybe for a little while, but not if exposed to elements. When we were developing the business and establishing the pricing of the service, we stripped an AMC Matador down to the bare metal in a couple of hours using wet blasting for dust control. We left it bare and the hood eventually flash rusted after a while.

It's not salt, it's baking soda. It's not corrosive.

Kevin, as far as harder coatings like epoxies and surface issues like rust, there are various grits of sodium bicarbonate that are available, ranging from powdered sugar to playsand-like particle size. Obviously, the soda particles are nowhwere near as hard as silica, so they basically disintegrate when they hit the surface. However, if you look under a microscope, each particle has a number of sharp facets and that's where the cutting action comes from. You can actually strip paint right next to glass without etching the glass.

For light surface rust, the process works fine. For heavy rust, I would stick to aluminum oxide.

More information about the process is available here: http://www.armex.com/

Also, TimT worked on the statue project for which this technology was originally developed. He might chime in here.

[randywebb]

Right - it'll just wash off as it is highly soluble in water.

Also, be aware that altho the media isn't any problem, the stuff that is removed can be an env'l problem. I wouldn't be real concerned about dried bondo or most dried paints.

But - cars with lead filler will produce lead dust when blasted - a very very bad thing to deal with. If somebody did that near my neighborhood, I'd sue their ass until their ears bled... You also don't want to have a dozen irate mothers finding out that their kids have high Pb levels in their blood... you'd be bankrupt in a real hurry.

[RickM]

Lead dust? I'd think lead is too pliable and would absorb the impact of the media. I'll venture a guess and say the blasting would goe further than the paint or surface rust.

[randywebb]

I wouldn't bet my kidneys or liver on that...

Remember we are concerned with very tiny amounts here.