The process this first part went through is as follows:
I suspect we’ll need to introduce something before bead blasting maybe even before the first degreasing. But not sure what.
Anyone have insights that might help?
Sanding?
Maybe a 120 grit
That’s pretty involved isn’t it considering we have a few hundred parts to work through.
I was thinking maybe a buffing wheel might work… but getting into the pockets and such would be more difficult.
Sanding using a random orbital sander) llll would be less involved than buffing since buffing is polishing.
For the inside parts, maybe 80 grit sanding sponge.
In the longterm, maybe add a finishing pass
Tumble finishing might work for you
This is the tumbler media we use at work to tumble parts. I think I tumbler could work really well for you and the large count of parts you are looking to process. Otherwise, as mentioned above a random orbit sander would work with a super fine grit pad, but it would take a while to process all those parts. Really aggressive bead blasting would be an option as well, either way. Both of those options would add a pretty significant amount of time compared to tumbling. ( and tumbling is hands off).
I leaning towards this too… do you have a recommendation for a tumbler that might work in our situation?
What about a recommendation for the actual media?
Seems like this step in the process, like many things in life is an uphill battle. It may be a struggle, but I know you will figure it out and beat it. Hang in there and keep up the good work.
I will talk with our CDL (corporate development lab) tomorrow to get specifics on the equipment/media.
Sent you an email with some other details.
I too think the tumbler is your best choice to try first if the grit on the tumbling media is sufficiently coarse enough to remove the tooling marks and not just polish them to a glorious shine.
However, if a vibratory tumbler isn’t viable, and you’re considering manual finishing, I recommend starting with an alternative to conventional sandpaper, specifically, “3M Radial Bristle Discs”. The initial recommendation below covers smaller-diameter discs suitable for detail work.
For finishing brass engravings produced on my CNC or laser etching, I’ve had excellent results using these radial bristle discs. They’re constructed from a flexible polymer with abrasive particles embedded directly into the bristle structure during the manufacturing process, allowing consistent material removal without generating excessive heat or altering fine details, if you’re careful. The smaller discs come in a wide range of grits from coarse 80-grit to 1-micron polishing.
3M Small Radial Bristle Disc Set
https://www.amazon.com/dp/B0C2L3P6QH
For power, I use a Foredom rotary tool, which is designed for continuous operation and common with jewelry makers. However, a variable-speed Dremel is sufficient for intermittent or light-duty tasks.
For larger surface areas, 3M manufactures a 2-inch version of these bristle discs, oriented in an axial (flat) configuration rather than radial. While I haven’t yet tested these larger discs personally (they’re on my wish list), they appear well-suited for applications such as wheel polishing or larger metal surfaces.
2-Inch Bristle Disc
https://www.amazon.com/dp/B01MSU3PYQ
Quick-Change Holder for 2-Inch Disc
https://www.amazon.com/dp/B003VOO92M
Maybe some kind of chemical etching bath before bead blast? Honestly, bead blasting should be more than enough though. If glass bead won’t remove tool marks from aluminum, it’s most likely your gun/delivery system might not be up to par. Try experimenting with different media and air pressure. Also, there have been occasions when I’ve found that used media is more effective since it’s all broken up and has sharper edges.
Hey all,
with wood, this would always be my first approach, but I lack experience with metal. Also on wood, I would use a radius cutter (⌀ 8 mm ball nose) as last pass. That takes time (the machine, not you) but leaves a perfect finish. No sanding necessary.
But when using endmill, very precise adjustment of tool perpendicularity to machine table of course.
I will note that these are purely visual… you can’t feel anything with regards to these machine marks. It is absolutely smooth.
Yes but the look is important too 
At least for tech freaks
Hi Daniel… It is usually easier not to reinvent the wheel. I believe you could use the advice of experts in the field because the requirement is for a long-term solution.
You could try asking these people based in NH and NJ. At the very least, I expect they could point you in a useful direction.
140 Ethel Road West, Unit U
Piscataway, NJ 08854-5951
71 Hobbs Street, Unit 106
Conway, NH 03818
I havent done more than etch the surface of metal myself too, but the video I posted, they had some sort of bristle brush that rubbed the surface. Thats what I was referring to with the finishing pass.
Ah okay. I’ll have a look
Edit: I see, a silicon carbide infused nylon brush
So the correct term is obviously end brush
Learning something new everyday
