Surface preparation method

[tech20]

Hi guys,
Are sand blasting & shot blasting processes same?
These are related to surface preparation before painting.
If they are not same, which one is better and why?

Thanks

 

[tygerdawg]

Assuming substrate material = steel...
Sand blasting in many cases is used to remove previous coatings, rust, scale, etc., down to bare steel. Also changes surface texture.
Shot blasting will do this also, but has added property of cold-working the surface of the steel & makes the surface harder.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[tbuelna]

I would say that the terms "sand blasting", "grit blasting" or "shot blasting" all imply a similar process. That being a process intended to remove something (paint, corrosion, etc) from the surface of a component, usually a metal component. The term "shot peening" would imply a much more energetic and controlled process where metal/ceramic shot is directed at high velocity onto a metal surface to put the surface layer into compression.

I think the best terms to use for describing a process to clean a surface are either "media blast" or "grit blast", since there are numerous types of abrasive media used such as sand, glass beads, baking soda, walnut shells, ceramic particles, metal slag, or even frozen CO2 powder.

 

[robyengIT]

doedn't matter what system, the result is important : if the substrate is metal, I hope files attached can help

 

[tech20]

Does shot blasting process significantly harden the surface?
It's a new information for me.

 

[rb1957]

shot blasting, or shot peening, is intended to create a compressive stress in the surface layer, to improve fatigue or corrosion resistance.

sand blasting, IMHO, wouldn't create this, and is more a surface preparation for painting.

Quando Omni Flunkus Moritati

 

[tbuelna]

rb1957,

steel shot blasting is a process commonly used to clean metal parts with no intention of altering the mechanical properties in the surface of the component. A good example is the cleaning of sand castings using Wheelabrator machines. The shot blast removes flash and contaminants like mold sand from the casting surface, and produces a uniform surface texture, but it is not intended to alter the mechanical properties of the casting.