Q- how would one attempt to grit/sand blast the tinfoil Robbit blades?
Steve
The way a surface is grit blasted depends upon the type of material. When one talks about grit blasting, the common perception is that you blast the **** out of the surface, such as if you are taking rust off a highly corroded steel ship hull. This is not necessary for surface preparation for painting or bonding because
all you need to do is to remove the existing oxide layer. You are NOT trying to "roughen" the surface.
Now for relatively soft materials (aluminium for example) you would reduce the pressure in the gas used for delivery, but for harder materials such as stainless steel, you need to use a higher pressure.
The blasting medium is also a consideration. The medium must actually cut the surface to remove the oxide layer, so soft materials such as walnut shells will not be suitable. We have usually relied on aluminium oxide powder about 50 microns. We also did not recycle the powder to prevent cross contamination.
The propellant gas may also be important. Many people use shop compressed air, but that has a severe risk of oils and water from the compressors. We always use dry nitrogen from cylinders used to compress shock struts etc. Dry, clean and inert; that works well. Just be careful if you use this in confined spaces because the user may develop a blue face and fail to return at tea time.
Regards
Blakmax