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View Full Version : Media blast and overlays?



Crystal Chambers
02-03-2010, 05:18 AM
I'm considering media blast with an overlay and have a few questions if anyone can advise.

Is media blasted MHS easier to scratch?
How much surface is removed?
Will it make overlays noticeably looser?
If so would a clear PC protect it and still fit an overlay tightly?

Kal El Rah
02-03-2010, 02:26 PM
I'm considering media blast with an overlay and have a few questions if anyone can advise.

Is media blasted MHS easier to scratch?
How much surface is removed?
Will it make overlays noticeably looser?
If so would a clear PC protect it and still fit an overlay tightly?

#1 = No
#2 = None, it actually hardens the surface
#3 = No
#4 = Your choice

Crystal Chambers
08-03-2010, 05:36 PM
Just for the record it's not really easier to scratch but scratches show up more on mediablast in my experience.

acerocket
08-03-2010, 06:56 PM
In my experience, media blasting does 'appear' to scratch easier. Aluminum scratches pretty easy anyways, but I think the media blast surface tends to show the scratches more giving you the effect of scratching easier. Media blasting does however tend to show oils more easily. If you have oil on your hands, you will know it right away with media blasted surface.

You are not actually removing any of the surface. You are peening it. That is, you are pounding extemely tiny little dents in to the surface (glass, ceramic or metal bead). You end up with a dent and a raised lip at each impingment. Think something like a billion micro meteor impact craters all over your part. It does not harden the surface. You can work harden a surface by blasting, but you need very high pressure and specific media - not likely to happen given the home blasting setup Tim probably uses.

No, it will not make overlays looser - nor tighter. Unless you are running rediculously small tolerances between your part and overlay.

You could definitely protect the surface with a clear powder coat (or clear paint). But the powder coat/paint will add thickness to the part and make a previously loose fitting shroud much tighter. I would suggest powder coating the part first and then making the overlay.