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Degreasing of metal fasteners before shot blasting and dip spin coating

I want to know, if the process of degreasing is necessary before shotblasing and dip spin coating of fasteners.

SANJAY CHITLANGIA
FASTENERS - India
2005

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If the fasteners have no grease on them, degreasing is probably not necessary, and you can just shotblast them.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

It would help to know what you are dipping into prior to spinning. My guess would be hot dip galvanizing.

David Jaye
Houston, Texas
2005

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Generally in fasteners you might be doing a Magni or Dacro or PTFE coating through dip spin process to meet the hexavalent chrome restriction. Just before loading the product if you find oil on your product, you need to degrease it. Otherwise degreasing is not required.

Right. How will you assess whether there is oil or not? Take a beaker and fill it with water (approximately half of it, do not make the beaker overflowing). Then put 5 nos of sample fastener from the bulk lot. With a glass stick or plastic stick stirr the water in beaker. Then allow it to settle for 5 minutes.

Now you check it on the surface layer of water. If you find rainbow or oily substance on the surface of water, you have to do degreasing of fasteners before shotblasting.

V. G. Rajendran
- Trichy, Tamilnadu, India
2005

PLEASE INFORM THE CORRECT PROCESS OF DEGREASING OF FASTENERS BEFORE SHOT BLASTING AND DIP SPIN COATING. IS THERE ANY METHOD WHERE THE PROCESS IS ENVIRONMENTAL FRIENDLY AND THERE IS NO GENERATION OF ANY TYPE OF POLLUTION.

SANJAY CHITLANIGIA
FASTENERS - DELHI, INDIA
2005

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Grease is a pollutant, so no matter what method you use to remove it, the medium you have removed it to is a pollutant. Degreasing is a science and industrial art that has been practiced and is still being practiced in tens of thousands of metal finishing shops for many decades, so to ask for the 'correct process' is similar to asking what is the correct method of transportation. Probably the least polluting method of precleaning before shot blasting, but one of the most expensive, would be vapor degreasing with n propyl bromide. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005