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-----Improve surface finish of cast iron by washing with abrasive powder
How to increase the surface finish of cast iron after grinding by washing it with some powder, any chemical powder.
Arun Cemployee - Chennai, Tamil Nadu, India
March 16, 2011
Hi, Arun.
Such abrasives powders smooth the surface through mechanical action rather than chemical action. So it will be a question of how to make the abrasive powder rub against the parts. Tumbling barrels, or vibratory finishing machines, or abrasive blasting, or honing, or something similar will be required -- not simple washing (as far as I know).
Regards,
Ted Mooney, P.E.
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finishing.com - Pine Beach, New Jersey
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March 17, 2011
Ted is correct, but to answer this question more accurately we need to know what are your part sizes, maybe volume, what is your surface finish now and what surface finish you want to achieve?
AF Kenton
retired business owner - Hatboro, Pennsylvania
March 21, 2011
There is a way. it goes by several names like wet blasting and vapor honing.
A slurry of very fine abrasive is aspirated up into the output nozzle much the same as a siphon dry blast cabinet. The other way is a similar slurry is pumped via a mechanical pump and would loosely be compared to a pressure blast system.
We had one that was built by a British firm. The recommended abrasive was so fine that it did not do much. We switched to using worn out aluminum oxide, probably about 600 to 800 grit.
This worked very well for us. We were able to remove the chromate conversion coating from cad plate with no measurable loss of plate. While it was not suitable for rust removal, it left the surface of a piece of steel with a much smoother surface than a similar dry blast.
The aluminum oxide was hard on nozzles, pipes and pump impellers. For us, the extra maintenance was an acceptable cost of using the cabinet.
- Navarre, Florida
March 22, 2011
I want good surface finish in cast iron cam shafts, Tell me the ways of getting it.
Quality Engineer - India, Tamil Nadu, Chennai
April 18, 2011
After looking at your part, I don't think a secondary operation to improve the surface finish is the way to go. I suggest the manufacturing operation be modified to include working the entire piece to the proper finish.
AF Kenton
retired business owner - Hatboro, Pennsylvania
April 25, 2011
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