What is Baking Soda Blasting?
by Dave Weakley aka Dr. Gel
American Boat Restoration
Previously published in:
Boating On The Hudson & Beyond
reprinted with permission
Soda blasting is a safe paint stripping and cleaning process that uses bicarbonate -of- soda media delivered by means of compressed air through a specially designed pressurized blasting pot system onto the area to be cleaned. It removes paint and contaminate without harming the underlying surface.
This is how the process of soda blasting works. Soda blast particles remove surface contaminate by the energy released as the particles explode when pressure driven into contact with the contaminate surface. The resulting release of energy disrupts the contaminate surface thus leaving the substrate unaffected! No heat no sparks!
Blast material is baking soda and yes; you can make biscuits with it! It is an environmentally, non- toxic, non-hazardous food grade material that is 100% water soluble and environmentally friendly. The size of the soda particles are coarser than those you have in your baking soda box at home.
It is an excellent paint stripping method for fiberglass boat hulls and can also be used to strip engine parts, brick, concrete, hardwood, surface rust, paint and rust from cars, stains, airplane parts, graffiti, fire restoration, degreaser for kitchen and mechanical components and more.
Soda blasting was used to restore the soft copper on the Statue of Liberty during its restoration in 1982.
The copper skin is only 3/32 of an inch thick; it was essential to use the least abrasive material to strip the six coats of paint and layers of coal tar on its interior.
Why use soda to strip bottom paint hulls when other blasting medias are available?
To strip a soft surface properly a soft blasting media should be used. Think of throwing snow balls at your hull verses stones!
There is a tool for every job and most blasting medias should not be used on fiberglass hulls.
Here are some examples; sand blasting strips rust and paint from steel. It is too hard to use as a striping media on fiberglass. It will remove barrier coat, gelcoat and the underlying fiberglass laminate. Black beauty, a.k.a. .slag is sharp, dirty and one of the poorest choices of bottom paint stripping media. It will remove paint and rust from steel but it is much too hard and one of the worst blasting medias to use on fiberglass. It like sand will remove much more than just the paint. It will damage chrome, aluminum rub rails, bearings, sliding windows, glass, etc. The residue from black beauty can stain gelcoat.
Unlike soda blasting, sand and black beauty remove coatings by wearing them away.
On the media Mohs Scale of Abrasives 9 is the hardest. Hard abrasives have a rating of 7 or above. Soda (sodium bicarbonate) has a rating of 2.5 the lowest and Sand (silica) is 7 and mineral slag/black beauty 7.5.
Reasons why you may want to strip the paint off a hull:
- If there are numerous repairs that need to be done; e.g. blistering, cracks, etc.
- To remove an excessive amount of bottom paint and prep for new application. How much do you think 20 costs of bottom paint weighs?
- To permanently remove for appearance and hull performance for those boats that are not kept in the water all season – How many irregular and ugly surfaced hulls have you seen?
- If the paint is peeling and falling off because of poor adhesion all the paint needs to be removed. The hull can be properly prepped for new barrier coat and bottom paint. A shiny hull with peeling paint has no protection from water absorption that can cause osmotic blistering a.k.a boat pox.
- Bottom paint can hide a lot of unseen problems!
It is helpful to have a knowledgeable, experienced fiberglass repairer soda blast the hull because even soda blasting is mildly abrasive and should be done correctly. During and after the blasting procedure an expert can inspect and evaluate the condition of the hull and recommend the proper repairs and surface coatings.
Soda Blasting is an eco- friendly, FDA approved paint remover!