Metal finishing Q&As since 1989

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Bead blasting

I wonder if anyone can answer the following question to help my company with a bead blasting query we have.We have recently developed a new product which has a stainless steel tubular frame manufactured from 5 parts welded togeather. We have specified on each of the 5 items that they are stainless steel 304 S31 stock bar with no finish. We then get the parts welded togeather and then send them to a company to carry out the bead blasting.We were under the impression that in getting this bead blasting done this would cover up any surface marks on the frames, but we are finding that this is not the case. Should we have another process, or specify some finish on these items prior to the bead blasting process.I would appreciate any advise on this because at the moment this has got a little bit political within our company and there are a number of heated discussions going on

Pat Curtis
weigh labelling machines - Haverhill, England
2005

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First of two simultaneous responses --

Your statement "this would cover up any surface marks" is not clear. What exactly is the problem? Also you mention bead blasting. I assume you are working/cleaning with glass bead? There are some more aggressive media materials that paint will adhere too better.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2005

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Second of two simultaneous responses --

Bead blasting can obliterate some surface imperfectioins, but as you have learned, there is a limit. It may be possible to improve your situation by using coarser bead, higher blasting pressure, longer blasting time. I'd suggest you work with your blaster to see what he can do. beyond that, you may need to improve the fabrication and handling of the components to minimize damage, or you may have to do some hand work, grinding, filing or polishing prior to bead blast.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
2005

You could also have the material stripped down by using a straightliner. If you have a large quantity of these parts that you are doing it would be ideal. You could find a decent used straightliner for about 2000 dollars and belts genuinely run about 34 dollars a belt depending on what grit you are using. But are you bead blasting to dull up the luster on the material? Or to reduce imperfections?

Brandt Hinton
- Elk River, MN, USA
2005