Tumbled finish?

G

gixxer

Joined
Sep 21, 2006
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Anybody try it? I have a tumbler that I use for reloading, have a bunch of walnut shell. I am going to try one blade I have prepped for HT with a satin finish just to see what happens. I know the satin finish is gonna go to hell but sometimes sacrifices are needed in the name of science!! I was looking online @ the gem tumbling websites, they have this powdered red rouge that you put in with the corncob/walnut. I also found 600grit silicon carbide powder for sale too. For kicks I am gonna make a knife blade tumbler out of a 5 gallon bucket, rollers and motor this weekend. Might try 12" PVC instead. Depends on how involved I decide to get this weekend.
 
I can do a before and after...

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Tumbler.jpg
 
Cool. I should be able to do the 5gal bucket deal for well under $100. The big cost is the continuous duty tumbler motor. There are a few different sizes, and I figure I would need the larger one. Its a replacement for a 12lb production tumbler. Thats going for about $50. I guess a heavier duty rotisserie motor might work also.
 
I got the idea from the issue of blade with the razel on the front. There is an article in there about blade finishes. Boker uses this huge bathtub sized vibratory tumbler with ceramic media. Anyhow, I did not add any cartridge brass polish to the media this time, that is another experiment. Come to think of it, there is quite a bit of residue on that batch that I have going now. I am kinda lazy when it comes to changing out my media. When I wake up it will be 7 hours, check and photo.
 
butcher_block said:
if it works i will think about making a big tumbler
deker i ahve that spar morot too what you think
Click to expand...

For a giant vibratory tumbler maybe, but definitely not a regular "tumbler tumbler"...unless you want to tumble at 3600RPM :)

-d
 
7 hours... although the photo does not pick it up, you can tell there is a little bit of polishing. One thing I read on one of the websites is that the walnut really removes no metal, so if you have any scratches left on the metal they will still be there. Guess another experiment is in order with the 600grit SC powder, maybe even get some fine grit ceramic. The walnut would work but only if you are well on your way to 1500grit more or less, and as i suspected, you need like 12hr at least. no biggie though. If you time it right, you could toss your almost ready blade in, forget about it till the next day, and work on other projects while your blade is tumbling.
Other observations, I tried more than one blade at a time, and they ended up clanging together in the same spot. not condusive to a nice finish, so had to go one at a time with that small tumbler. I am gonna order the 600grit SC and look for the finest ceramic media that I can find. but, I hope that with enough media in the 5gal bucket, I could do nmore than one at a time. I will post the link to ideas on how to build a tumbler with that bucket later tonight. top pic is before.
Before.jpg


After.jpg
 
To tumble finish steel items you need shaped ceramic media.I gave Higgy a unit and a bunch of media a year ago. Don't know if he ever did any blades in it? You could ask him about it.The media comes in various shapes and grits.The right combination will yield a nice matte finish.As for polishing with a tumbler, that is another thing entirely.
Have fun with your rotary tumbler,but a few words of advise from one who has made one....DON'T make it from a drywall bucket.It will fail very soon. Using 12"PVC would work I think.Walnut and rouge is used to polish softer metals like brass, gold ,and silver.The barrel speed is determined by the barrel diameter and the drive wheel diameter. On a large tumbler ( I built a large 20" one when I used to do large casting batches, to clean up and polish castings)there are three "cradle" shafts that the barrel sits on. The outer two have free rolling wheels (I used skate board wheels). The center shaft turns in bearings and can be raised and lowered (to get proper friction contact) and has 1" fixed rubber wheels on it. This shaft is in turn driven by the drive motor.The drive motor has a 1" pulley and the shaft end has a pulley size calculated for the barrel speed desired.The unit I had used a 12" pulley. Even though the motor was small (1/4HP) and the drum was large and heavy,the unit still ran steadily at a low RPM,due to the high ratio.It turned at about 60RPM IIRC.
Other things that make a tumbler work better are keeping the rolling and agitation high. The insides need to be multi-sided,not just round. On a small gem tumbler,that will get by,but a large finishing unit needs to be anything from hexagonal (Very high abrasion and impact) to twenty sided (less violent agitation).Send me a PM if you need construction specifics.
Stacy
 
Stacy, you are spot on. I did more research today @ work today, ordered a couple bags of ceramic media, the small stuff to get in the plunge cut real good, a couple pounds of 600 grit silicon carbide, and for kicks a pound of powdered red rouge. I had planned on using RTV to isntall some agitators on whatever barrel I get around to. I was gonna use skateboard wheels and plain threaded rod for support. How to drive it? I have not gotten that far yet. Got the motor picked out though. I did realize that my reloading tumbler is on its last leg. It was practically screaming for mercy! Time to upgrade. The larger benchtop models with a 17" mouth are like anywhere from $500 to $900, so that is out of the question. I did find this though.

http://dillonprecision.com/template/p.cfm?maj=16&min=0&dyn=1&

The CV2001 is pretty big, and the price is manageable. I always wanted to tumble FIVE HUNDRED 375 Rem ultra mags at once!!! I was looking for one with a bigger bowl so it could be a multitasker. I am still gonna press on with the PVC/bucket option. Here's another site where I got some of my motivation.

http://www.metalsmith.org/edu/equipment/tumblers.htm

http://www.metalsmith.org/edu/equipment/tumblers/foster.htm
 
Based on my knowledge of super-finishing bearing grade steels, the ceramic will do what you're after. You will need to add some type of "very light" etching solution. I can't stress how non-aggressive the etch needs to be. A citrus acid or something similar. The light etch will be cleaned up by the ceramic beads and give the knife steel a very nice burnished look. The ceramic does not have to be very small. The ceramic can be the size of peas, or even slightly larger. One thing that will help is having the ceramic medium be of irregular shapes and sizes. The etch eliminates the need for any kind of abrasive.

I think you'll be pleased with the results. I've thought about setting something like this up in my shop, once I have more room.

Vibration instead of tumbling will yield a more consistent result also.

Hope that this helps.
 
Would straight 100% simple green be considered a light etchant? Over the timepsan of hours? Hopefully when I get that CV2001 tumbler I will be able to put up to 10" long pieces of steel in there and have it tumble right. The ceramic I ordered is 45deg cut cylinders. I guess using the etchant would be easier to clean up than seperating SC and ceramic.
 
I have used glass beads (100 gt) but it takes a long time to get very little finishing done. I did not see any benefit it had over regular finishing techniques.
 
I prefer pyramid shaped media.For an etchant/lubricant/surfactant try 1 quart water + 1 TBS white vinegar + 1 Tbs tumbling soap. Use enough of this mixture to keep the media wet and it should etch and polish at the same time.
Stacy
 
interesting question. Would I use an etchant if I am tumbling stainless? Or just use tumbling soap?
 
Well, the tumbled finish is satin also, but with no lines. With the wheel, either nylon, scotch brite, or even cork or leather with emery there are lines. I do have a scotch brite wheel, and it does indeed work faster. I was just trying this to see what happens. I do still want to run a blade for 24 hours with walnut and red rouge.
 
Well, I got the ceramic (not enough of it honestly). After some trial and error, I got the ratio of filler to ceramic with straight simple green for burnishing soap going. I did not have enough media to fill the bowl, but I could still get that small blade going. I had it going for about 8 hours, will take pic tomorrow. Shut it down for tonight. The look is almost .... frosted! pretty cool though. I will add pics tomorrow. ordered a couple more bags of small and large ceramic media.

I got a bag of straight 600grit SC, that was a MESS! I tried using it dry with the ceramic, then got the BRILLIANT idea to add some moisture. The stuff turned to CONCRETE after an hour!!! That was such a pain in the butt to clean up. Other observations, you still need to clean up your scratches on the blade or they will come through (unless I did not do it long enough, only time will tell). Tomorrow I will let it go for all day.

once again, before...
Before.jpg

After
After2.jpg
 
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