Quote:
Originally Posted by babymog
I suspect that what the poster is cautioning about / worried about, is stress-risers created by the pits in the surface. Although it is a concern in aircraft parts etc., in the wheel surface it has a relatively minor effect on the strength of the wheel....
So it is possible to weaken the wheel with sandblasting, but careful media blasting and polishing afterward can be safe.
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I'm very appreciative of your detailed explanation. Everything makes sense, from a scientific perspective, but the practical application suggests to me that what I have already done is acceptable.
The blaster was 1/3 full of some old recycled sand that I had swept up, strained, and returned to the hopper for 1 more use. It started out as #0. I continued to fill the hopper for this job with fresh #00. As I described in the link to the Toyota wheels I initially posted, each wheel was spotless after no more than 45 seconds. A lot of the original paint was still on them, just dulled by the sand. My intent was to give the self-etching primer more 'bite', and to do the cleaning job as quickly and easily as possible, not to strip off the surface of the metal. When the job was done, and after giving the backside of the rims a quick scouring, the hopper was almost empty. As before, I collected and strained the used sand, much of which was now almost powder.
As PanzerSD noted, "one would have to be a REAL idiot to harm the integrity of a wheel by sand blasting." I assume this would be the aggresive application of #1 or #2 silica from a high pressure industrial type sandblaster at air pressures exceeding the 100psi of my 5 HP home garage compressor, which actually only puts out this pressure for 30 seconds or so. It requires a recovery time of about 2 minutes to bring it back up from 80lbs after the 45 seconds of blasting each wheel.