How to Soda Blast with a Dana-Ridge Wetblast Machine
- Friable – soft angular grains readily fracture into smaller particles intensifying the cleaning action while softening the impact on substrates.
- Water soluble – eliminates media residue concerns and simplifies clean-up
- Safe to use on virtually any substrate, including delicate surfaces, rotating equipment and moving parts but still able to remove coatings.
- Able to be washed out of internals easily meaning no damage to moving parts.
- Contains no free silica
- Contains no solvents or caustic chemicals
- Environmentally friendly
- Non-toxic and non-hazardous as defined by the EPA and OSHA – with a pH level of 8.2
- The angular shape of the sodium crystal has a scouring effect on the substrate that will virtually clean any coating from the surface
- Unable to remove heavy rust and scale
- Gives a matte finish (may be an advantage if it is the desired effect)
- Shorter media life
- Slightly alkaline, causing crystals to form on blasted parts (this can be neutralised in a slightly acidic solution of vinegar and water after blasting)
- In a dry sandblasting cabinet, water is an issue (not in our wet system though)
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…
(26 Litre sump)
(28 Litre sump)
(125 Litre sump)
|% Conc.||Approx. kg Sodium Bicarbonate|
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.