blasting material

[rezabertoni]

Hi folks,
I am a new player in thermal spray coating. We have opened a new workshop in Indonesia. I would to ask what kind blasting material that often been use for pretreatment process? could you give me a few alternative for it? Thx.

Br,
Reza Bertoni

[Gordon]

Hi Reza

to the Surface Engineering Forum.

I would stress the word GRIT when talking of blasting materials for surface preparation for thermal spray. Shot or bead blasting does not produce a suitable texture or "sharp etch" required for good bonding.

Angular chilled iron and aluminium oxide based grits are recommended and are probably the most widely used abrasives for thermal spray. For some special applications more exotic materials like silicon carbide are sometimes preferred. The use of cheaper abrasive grits like copper slag are used for zinc anti-corrosion coatings, but I would not recommend them for other thermal spray coatings, unless they are used to do the brunt of the cleaning, prior to final blasting with better quality abrasive grits.

[rezabertoni]

Hi Gordon,
Thx for the information. How about silica sand or quartz sand, can it be used for grit? Thank you.

(11-25-2008 01:14 PM)Gordon Wrote:  Hi Reza

to the Surface Engineering Forum.

I would stress the word GRIT when talking of blasting materials for surface preparation for thermal spray. Shot or bead blasting does not produce a suitable texture or "sharp etch" required for good bonding.

Angular chilled iron and aluminium oxide based grits are recommended and are probably the most widely used abrasives for thermal spray. For some special applications more exotic materials like silicon carbide are sometimes preferred. The use of cheaper abrasive grits like copper slag are used for zinc anti-corrosion coatings, but I would not recommend them for other thermal spray coatings, unless they are used to do the brunt of the cleaning, prior to final blasting with better quality abrasive grits.

[Gordon]

Hi Reza

I would not recommend using sand (i.e., silica) in any kind of blasting operation due to the inhalation hazard of the free silica.

[bry1975]

Silicosis is a very nasty disease:-



Silicosis (also known as Grinder's disease and Potter's rot) is a form of occupational lung disease caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in forms of nodular lesions in the upper lobes of the lungs.

Silicosis (especially the acute form) is characterized by shortness of breath, fever, and cyanosis (bluish skin). It may often be misdiagnosed as pulmonary edema (fluid in the lungs), pneumonia, or tuberculosis.

This respiratory disease was first recognized in 1705 by Bernardino Ramazzini who noticed sand-like substances in the lungs of stonecutters. The name silicosis (from the Latin silex or flint) was attributed to Visconti in 1870.