Bead blasting

[Don Halter]

Santa got me an early Christmas present...a medium sized blasting cabinet. I used to used glass beads back when I worked down at Nasa. I thought we used something on the order of 120 grit. The only thing I found here locally was 80 grit. For those of you who do bead blasting on blades, what grit and pressure settings have y'all found to be best for blades?

P.S. Anyone coming to the monthly knifemaker meets at my place is welcome to use it, as well as the hot bluing tank!

[nozh_scrap]

Thanks for posting this man. I'd like to know the same.

[Ray Rogers]

I'm using about 120 grit glass beads at around 60 psi. You can always start at low pressure and repeat at high pressure until you get what you want. At low pressure, I wouldn't be surprised if you could get good results with just about any grit. You probably don't want to dent the suface when bead blasting. Soft glass beads on a highly polished surface at low pressure create a softened and diffused look .....

[Don Halter]

I figured it was somwwhat less than what I was used to. We used to use coarse grit at fairly high pressure (~80 - 100 psi), but we were stripping paint, surface coatings and welding scale...and wanted to do it quickly! A second unit had about 120 grit, but I couldn't tell you the psi. I'll give it a shot this weekend on some scrap and see what looks best. I went ahead and got the 80 grit since that was all that was readily available.

[AUBE]

did you check with your local automotive machine shops? a few of ours carry or can order many different grits.

[Don Halter]

Interesting effect, but not really what i wanted. the 80 grit glass beads at 75psi give an awsome finish on the UNHARDENED portion of the knife, but not the blade. It barely scratched the hardened blade surface. The temperline is clearly visible as a boundry where the uniform sating finish and the still partially polished section is. It makes perfectsense when you think about it and it's interesting, but not at all what I want on this one. Looks like it'll take a while to even out the finish. On a non-differentially hardened blade, it wouldn't be a big deal as it puts a very slight satin non-glare finish. It's just such a contrast between the hardened and non-hardened that it doesn't flow with the rest of the knife. I have all day tomorrow to mess with it, so I'll even it out. Anyone else had interesting effects like this?

I'll check out some of the auto body shops and see what I can find.

[TexasJack]

Hey Don, they opened a Northern Supply (I think that's right) on 45 about halfway between the Beltway and FM1960. I stopped in there one day just to see what kind of stuff they had and noticed that they had quite a variety of blasting materials, including several grades of glass beads. The place is kinda like HF, but they have good stuff along with the import brands.

[Don Halter]

Cool, I'll have to swing by there next time I head down to Houston. We're pretty limited up here in the Mecca of Civilization otherwise known as College Station. I'm sure someone up here has it...it's just a mater of actually finding them!