Soda Blasting with a Dana-Ridge Wetblast machine Q & A
At Dana-Ridge we often get enquiries about soda blasting and asked if it’s possible in our wetblast machines. Sodium bicarbonate (NaHCO₃) is a soft, granular, friable, sharp, benign blast media.
NOTE: Prior to using sodium bicarbonate on your part always do a test patch on a similar material to determine its suitability
Can you use soda in a Dana-Ridge wetblast unit?
Yes. Not only is it possible but it’s actually better than a dry setup. It lasts longer and you don’t have to worry about it getting wet as you do with a dry unit. Having it contained in a cabinet means it eliminates the clean-up time associated with an open system.
When would you use it?
It is sometimes used in the automotive arena such as blasting oil galleries, carburetors, diesel pumps, injectors It is used in a variety of applications for the removal of coatings such as soil, paint, grease, oil, carbon, and light surface rust from just about all substrates. It will not remove heavy rust however.
Why would you use it?
Anywhere where you have an assembled part and you either want a matte finish or can’t easily clean out remnant media.
What kind of finish will it give?
Contrary to a widely held belief, soda will not give a nice bright surface. It will give a matte finish.
Advantages and Disadvantages of Soda Blasting
Are there different sizes?
There are several grades of granular sodium bicarbonate available from fine (< 63 microns) to ultra-coarse (< 270 micron). For quick cleaning results it is recommended to use the ultra-coarse grade material.
Do I have to use it as a “soda only” machine?
You can change the media out to whatever you want. If you change from a media such as glass or oxide or garnet and the like, you would need to make sure you clean out any remaining media from behind curtains and split the pump to clean out any particles. If you’re using soda with the intention of avoiding damage inside assembled parts then it’s worth taking the time to clean it out well.
Is there an alternative?
Glass bead is more commonly used than soda for most applications. It gives a bright finish and can remove rust. If you can disassemble the part, then you can avoid getting bead where you don’t want. There are a couple of other tricks to avoid getting media where you don’t want it
How to I set my machine up for soda blasting?
(A 10-15% vinegar, 85-90% water solution is all that is required)
Charging the machine for use
How much media do I need to super-saturate the sump?
The amount required is dependent on the sump water temperature. The table at the very bottom of the page will indicate what percentage to add. For example, if a comet machine has a 28L sump and the water temp. is 20 then according to the chart you would add 9.6% of soda which is 2.7kg of soda.
We’re not done yet though. Now we need to add some more (see the following) …
How much extra to add after that?
Now that we have super-saturated the water as per the above step, we need to get our blast level up to around 25-30% which is the optimal blasting range. The following table will show the amount to add for our 3 most popular machines…
Do I have to top up?
When you are blasting and adding fresh water with the windscreen spray wash you are further dissolving your blast media. Whilst the loss of blast media with this is small (nominally 0.2 kg per blasting hour) the rate at which the sodium bicarbonate blast media is dissolved is dependent upon how much fresh water is added into the machine so keep the windscreen wash rate to a minimum.
As for the rate of consumption while blasting it can depend on variables such as the air pressure used. When it has impacted on the part enough times to the point of no longer doing useful work it will tend to dribble out the overflow.
It is recommended you use the media concentration jar to check regularly. Soon, you will be guided by experience and will have less use for the measuring jar. Too much media causes blockages, too little decreases productivity.