How should you prepare the surface for repainting after soda blasting

Posted on 25. Oct, 2012 by in Uncategorized

Now that you soda blasted your project, what is the next step?

We are asked this question often, at first I didn’t have the correct answers. I was told many things; from just don’t worry about it to, just plain water or dish soap and water or vinegar and water (nobody knew the correct ratio), and even alcohol and water. I now know that there isn’t a single stock answer to this question as there are many different kinds of substrates that we encounter with soda blasting and each one has its own treatment.

The main question to ask – is a coating going to be re-applied? If so, some sort of neutralizing and cleaning of the surface needs to be done. Baking soda (sodium bicarbonate) has a higher than neutral pH and contains some degree of salt (chlorides). You must have a clean, oil free and pH neutral surface to ensure that you won’t have a coatings failure after any type of media blasting. Coating failures after soda blasting can usually be traced back to no pre-paint preparation or poor preparation or incorrect preparation. Baking soda is a wonderful media that allows you to do things that no other media will accomplish, but you need to educate yourself about the media and follow a few simple steps after blasting.

Consulting with coatings manufacturers before application can reveal a wealth of valuable information and help insure a positive outcome to your project.

Here is a sampling of substrates and what we have found that works after soda blasting:

 Metals – HoldTight 102 is a great all around product that we have found. There may be other commercial products available, but none as comprehensive as HoldTight 102. Also recommended is Chlor*Rid Hold Blast.  

Fiberglass – HoldTight 102 and this includes boat bottoms and cars. Also for boats, Fiberglass Surface Prep #YMA601 by Interlux.

Wood – Sun Brite Wood Brightener – a citrus based wood bleach. Can be also used to brighten wood and remove rust stains.

Concrete – Hold Tight 102 or Sun Brite Wood Brightener.

Brick, block & mortar – Sun Brite Wood Brightener.

Links to the products mentioned can be found on our “links” page. Additional products that can be identified may be used. Please check with the product manufacturer regarding the proper use and application of other products.

Car guys, HoldTight 102 is the best product we’ve found to remove soda blast residue, cleanse the surface, and remove contaminates. Hold Tight 102 leaves no residue to interfere with new coatings and has a rust inhibitor built in. Hold Tight Solutions has been recommended by most major coatings manufacturers.

HoldTight 102 will eliminate all Salts, Chlorides and Contaminants (which cause flash rusting and coating failures) on metal.

HoldTight 102 will delay flash rusting for a 48 to 96 hours, allowing ample time to apply primer or coating of your choice.

HoldTight 102 will increase primer adhesion by up to 70%.

A quick message regarding vegetation:

Baking soda can burn or brown vegetation due to the pH of the product. Flowering plants that are more delicate seem to be more quickly affected. Leafy green plantings and common lawn grass seem less likely affected. Having said this, all vegetation can be affected by baking soda residue to different degrees depending on how much baking soda contacts the surface or ground and the type of vegetation. Use of breathable tarps to cover plantings around houses and decks is recommended. Follow removal of the tarps with a copious tap water wash down of the plantings. In areas where tarping is not practical, start with a generous pre-soaking of the plantings and ground the day before with tap water. Flood all plantings with tap water immediately after blasting. We have even used a lawn sprinkler to keep baking soda residue off plantings and to keep the ground wet during blasting operations. Baking soda is water soluble and use of additive free baking soda, like Natrium Products, will increase the likelihood of a good outcome.

There is no guarantee that you won’t burn vegetation with the above mentioned techniques – these are just some ideas that have worked. I always caution customers about the possibility of burning the vegetation. Because of what we can do with baking soda, most customers are happy to deal with any possible side effects.

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